The United Nations has designated 2020 as the International Year of Plant Health. I welcome the possibility of heightened awareness – although it could result in promises that are more optimistic than facts warrant.
APHIS
and probably other national and international phytosanitary bodies have planned
events to draw attention to the importance protecting of plant health. For
example, the APHIS website lists numerous meetings, some of which are special
events, e.g., Safeguarding 2020: North American
Safeguarding and Safe Trade Conference in Washington, DC, in August.Another event is a continuation
of the Entomological Society of America’s Grand
Challenges event, “Pre-border Prevention: A New Conversation on Invasive
Pest Pathways Through Trade” – which will take place in Orlando in November.
I
repeat that we should support the international phytosanitary community’s
efforts to raise political leaders’ awareness of the importance of preventing
phytosanitary disasters.
However,
at the same time, the international system that, for more than two decades, has
governed trade, with all its associated phytosanitary risks and regulations, is
falling apart.
The World Trade Organization – which is the basis for international trade rules – is under unprecedented threat. United States has blocked nomination of individuals to the World Trade Organization’s Dispute Panel. As of December 10, 2019 the Panel no longer has a quorum. As a result, experts expect countries to revert to the pre-WTO practice of bullying trade “partners” with whom they have a quarrel. They will probably erect tariffs and other barriers in order to force other parties to concede. Phytosanitary requirements might again be governed by individual countries’ bilateral agreements, leading to confusion and perhaps a “race to the bottom” in the name of facilitating trade.
Collapse of the WTO rules alarms me – despite my having criticized WTO restrictions on strong national phytosanitary measures over the past 25 years. (The restrictions were imposed by the WTO’s Agreement on the Application of Sanitary and Phytosanitary Measures – the SPS Agreement). For more details, see Fading Forests II. All-out country vs. country trade battles seldom put a priority on preventing the movement of pests. At least under WTO SPS, there has been a process for addressing pest problems.
Most phytosanitary issues – including development of international standards – are addressed under the International Plant Protection Convention. The IPPC is a separate organization from the WTO, so it might continue to function with fewer disruptions. Still, much of its clout comes from its recognition by the WTO SPS as the standard-setting body for plant health matters.
Rome – home of the IPPC
Of course, there are benefits associated with individual countries’ acting independently. Might the current collapse of trade rules allow the U.S. to adopt more stringent regulations governing introduction pathways of concern to us — for example, wood packaging? Can we hope that an administration focused on “America First” take aggressive phytosanitary actions to protect our agriculture and environment?
Unfortunately,
I see no indications that the U.S. Department of Agriculture – much less other
agencies – might seize this opportunity.
The United Kingdom has an even greater opportunity to act independently, since it is “Brexiting” the European Union in January 2020. In theory, the UK is now free to adopt its own phytosanitary measures. A House of Lords committee held extensive hearings to explore options in 2018.
Clive Brasier
While eminent plant pathologist Clive Brasier and others urged the UK to adopt more stringent rules based on a precautionary approach – for example, by banning imports of semi-mature trees with large root balls – the committee noted that the British government has often said that it wants to maintain “seamless” trade with the EU. It therefore seems unlikely that the UK will seize this opportunity to erect more effective phytosanitary barriers to prevent pest introductions to the islands.
Meantime, the European Union is making some mildly encouraging changes. Europe (including the UK) has the highest number of introduced tree-killing non-native pathogens of any continent – five times more than North America (Ghelardini 2017). Europe has a much more leaky phytosanitary system for plant imports than does the United States. See also Jung et al. (2015), Roy et al. (2014), the Montesclaros Declaration.
participants at the Montesclaros negotiation
In response to growing awareness of the plant pest threat, EU officials have gone through a multi-year process to strengthen phytosanitary rules governing movement of plants for planting (living plants, such as nursery stock). The process was described in Klapwijk et al. (2016) and discussed in my blog in October 2016. The new rules took effect in December 2019. The new European Commission regulation simplifies and harmonizes the “plant passport” system, under which plants are moved among EU member states. Plant imports that pose the greatest risk – called “priority pests” – are subject to enhanced measures concerning surveys, action plans for their eradication, contingency plans and simulation exercises. Plants for planting and plant products being imported into the EU will be subject to varying levels of restrictions, including prohibition of importation of those posing the highest risk. Less risky plants must be accompanied by a phytosanitary certificate issued by the phytosanitary agency of the exporting country (House of Lords report). The new system no longer depends on a list of harmful plant pests, but instead “sets out the conceptual nature of quarantine pests” and empowers the Commission to adopt measures to control certain pests (Klapwijk et al. (2016)).
Three years ago, Klapwijk et al. (2016) praised the new approach as a significant step forward. However, they note that the new rules still don’t provide for precautionary assessments of high-risk commodities. Nor do they actually restrict import of the highest-risk commodities, such as imports of large plants or plants in soil (my emphasis). Such restrictions still must be enacted separately. Organisms whose pest status is unknown will continue to be allowed into the EU. (See discussions of the impact of failing to curtail imports of “unknown unknowns” by Brasier (2008) and in Fading Forests II.
(While the U.S. also does not address organisms with unknown pest potential, it is much more stringent regarding sizes of plants, presence of soil or other growing media, and other issues. Furthermore, it has the NAPPRA process, which facilitates a more rapid response to emerging pest threats.)
Posted
by Faith Campbell
We
welcome comments that supplement or correct factual information, suggest new
approaches, or promote thoughtful consideration. We post comments that disagree
with us — but not those we judge to be not civil or inflammatory.
SOURCES
Brasier
CM. 2008. The biosecurity threat to the UK and global environment from
international trade in plants. Plant Pathology 57: 792–808.
Ghelardini,
L., Luchi, N., Pecori, F., Pepori, A.L., Danti, R., Della Rocca, G., Capretti,
P., Tsopelas, P. , Santini, A. 2017.
Ecology of invasive forest pathogens. Biological Invasions. June 2017
Jung,
T. et al. 2015 “Widespread Phytophthora infestations in European
nurseries put forest, semi-natural and horticultural ecosystems at high risk of
Phytophthora disease” Forest
Pathology. November 2015;
Klapwijk, M., Hopkins, A.J.M., Eriksson, L. Pettersson,
M., Schroeder, M., Lindelo¨w, A., Ro¨nnberg, J. Keskitalo, E.C.H., Kenis, M. 2016. Reducing the risk of invasive
forest pests and pathogens: Combining legislation, targeted management and
public awareness. Ambio 2016, 45(Suppl. 2):S223–S234 DOI 10.1007/s13280-015-0748-3
APHIS proposes to place numerous plant taxa on its list of plants for planting whose
importation is “not authorized pending pest risk analysis” (NAPPRA). Unfortunately, the proposal comes too late for some
pests; doesn’t apply to at least one significant pathway of entry; excludes some
highly damaging newly detected pathogens; and too often applies only to
agricultural pests. Nevertheless, the proposal is worth supporting – while
mentioning those caveats.
APHIS is accepting comments on the data sheets justifying the proposed listings until 24 January. The Data sheets can be obtained here. We encourage you to comment.
APHIS’
Regulatory Framework
Under
APHIS’ regulations in ‘‘Subpart— P4P’’ (7 CFR 319.37 through 319.37–14 …),
APHIS prohibits or restricts the importation of “plants for planting” – living plants,
plant parts, seeds, and plant cuttings – to prevent the introduction of “quarantine
pests” into the US. A “quarantine pest” is defined in § 319.37–1 as a plant
pest or noxious weed that is of potential economic importance to the United States
and not yet present in the country, or is present but not widely distributed
and is being officially controlled.
§
319.37–2a authorizes APHIS to identify those plant taxa whose importation is
not authorized pending pest risk analysis (NAPPRA) in order to prevent their introduction
into the United States. If the plant taxon has been determined to be a probable
invasive species, its importation is restricted from all countries and regions.
If the taxon has been determined to be a host of a plant pest, the list
includes (1) names of affected taxa, (2) the foreign places from which these
taxa’s importation is not authorized, and (3) the quarantine pests of concern.
APHIS finalized a rule giving itself the authority to place plant taxa in the NAPPRA program in 2011; it has previously used this process twice to restrict imports of plant taxa – most recently in 2017.
Plant Taxa that Host a Damaging Pest
or Pathogen
The proposed restrictions would apply to two plant families —
Myrtaceae taxa (when destined to Hawai`i), and the subfamily Bambusoideae
(bamboo); plus 43 other taxa that are likely to transport damaging insects,
pathogens, or viruses.
ohia in bloom; National Park Service photo
1)
All plants in the family Myrtaceae that are destined for Hawai`i.
The proposed restriction is intended to counter the risk that additional strains of the `ohi`a rust pathogen Austropuccinia psidii might be introduced and prove more damaging to native Hawaiian vegetation than the strain already present on the islands. (See description of `ohi`a rust here.
`Ohi`a
rust was detected in Hawai`i in 2005. Detection was followed by scientific
studies to determine whether different strains exist and, if so, whether they
posed a threat to Hawaiian vegetation. Under the circumstances, the proposed
action is disturbingly tardy.
Worse,
the pathogen was probably introduced to Hawai`i on imports of flower and
foliage cuttings, rather than entire plants or propagules. Unfortunately, the
section of APHIS’ regulations that governs imports of plants that can be grown
(“plants for planting”) does not apply to imports of cuttings (including
flowers). In the Federal Register notice, APHIS says it will issue a separate
proposal to tighten regulations on imports of cuttings and flowers. I hope they
move expeditiously on this rulemaking –
which will be more cumbersome in even the best case because it requires
a full rulemaking, not the expedited notice and comment process allowed under
the NAPPRA program.
It is disturbing that the proposal does not include the two Ceratocystis species that are killing millions of `ohi`a trees in Hawai`i link to DMF writeup. It is true that these were identified relatively recently – in 2017. However, other plant taxa proposed for inclusion in the NAPPRA category were also detected or determined to be the cause of a disease as recently as 2017.
ohia trees killed by Ceratocystis; Island of Hawaii; photo by J.B. Friday, University of Hawaii
2) APHIS proposes to include another
pest that might attack a native Hawaiian plant, Phyllanthus distichus. Another species in the genus, P. saffordii is endemic to Guam; it is
listed as endangered under the federal Endangered Species Act. Other Asian
gooseberries in the Phyllanthus genus
are grown in backyards in Hawai`i and other semitropical areas and there is
some interest in expanding commercial uses.
3)
APHIS proposes to include several plant taxa important in tropical agriculture
because of the threat that imports of those plants will transport diseases or
pests. These include two pathogens that threaten production of macadamia nuts (Neopestalotiopsis macadamiae and Pestalotiopsis macadamiae); and pests of
breadfruit, lychee, and durian.
4)
Some of the plant taxa that APHIS hopes to protect from new pests or pathogens
by placing hosts in the NAPPRA category are invasive. These include – in
Hawai`i – Syzygium jambos (rose
apple). It is named as a host of two
pests targetted by the proposed action – the `ohi`a rust pathogen Austropuccinia psidii and armored scale
insect Myrtaspis syzygii.
Euonymus bungeanus (winterberry euonymus) is in the same genus as
several plant species invasive across the continent. APHIS proposes to restrict its importation in
order to prevent introduction of the Euonymus yellow mottle associated virus
(EuYMaV), which has only that plant species as a known host.
5)
APHIS also proposes to add to the NAPPRA category several plant taxa that could
transport the Elm mottle virus (EMoV) because of the threat the virus poses to
several European elm species – and presumably also to North American elms. The
virus also attacks hydrangea and lilac.
In
several cases, some of the primary hosts of the target pest or pathogen are already
in NAPPRA for other reasons from some origins. Nearly all the woody hosts are
already required to undergo post-entry quarantine – which presumably APHIS now
considers to provide inadequate protection.
6) Also proposed are diseases or pests
that threaten grapevines and tomatoes.
Several of the proposed taxa are already
present in the US (including `ohi`a rust). Other proposed listings appear to be
precautionary actions to protect plant taxa that USDA expects to be
increasingly important economically in the future.
Plant
Taxa Proposed Because They Appear Likely to be Invasive
APHIS has proposed 26 plant taxa for inclusion in the NAPPRA category because they might themselves be invasive. Of greatest ecological concern are two taxa of mangroves which had been introduced by early 20th century plant explorer David Fairchild and have since been detected to be spreading in South Florida. These are Bruguiera gymnorhiza and Lumnitzera racemose. Also of concern is a vine that grows in Asian and Indian Ocean mangrove forests, Derris trifoliate.
Bruguiera gymnorhiza; Wikimedia Commons
Several proposed species are aquatic
plants that can form dense mats.
Other taxa proposed appear to possibly
threaten pastures or other agricultural uses.
Posted
by Faith Campbell
We
welcome comments that supplement or correct factual information, suggest new
approaches, or promote thoughtful consideration. We post comments that disagree
with us — but not those we judge to be not civil or inflammatory.
For more than a decade, most countries in the world have required that crates, pallets, spools, and dunnage made from wood be treated in accordance with the requirements of the International Standard for Phytosanitary Protection (ISPM)#15 that
this treatment be certified by applying an approved stamp to the wood. The goal
of the program is to “reduce significantly the risk of introduction and spread
of most quarantine pests that may be associated with that material.”
However,
experience and studies in both the United States and Europe demonstrate that the
ISPM#15 stamp is not a reliable indicator of whether the wood packaging is
pest-free.
1) In the United States, over a period of nine years – Fiscal Years 2010 through 2018 – U.S. Customs and Border Protection (CBP) detected 9,500 consignments harboring a pest in a regulated taxonomic group. Of the shipments found with infested wood packaging, 97% bore the ISPM#15 mark (See Harriger reference at the end of the blog). The wood packaging was from nearly all trading countries. 2) In the past two years, CBP inspectors have repeatedly found pests in dunnage bearing the ISPM#15 mark – as reported by U.S. importers of “break bulk” cargo into Houston. While most of the criticism of non-compliant wood packaging refers to countries in Asia and the Americas, at least one of the Houston importers obtains its dunnage in Europe.
3)
In Europe, a two-year intensive survey of wood packaging associated with
shipments of stone from China to the 28 European Union countries over the period
2013-2016 again found that 97.5% of
consignments found to harbor pests bore the ISPM#15 mark (Eyre et al. 2018). The scientists concluded
that the ISPM-15 mark was of little
value in predicting whether harmful organisms were present. (Eyre et al. 2018, p. 712)
As I have noted in previous blogs and policy briefs, the only in-depth study of the “approach rate” of pests in wood packaging, based on data which is now a decade old, found that 0.1% of incoming wood packaging transported a regulated pest (Haack et al. 2014). Given current trade volumes, as many as 17,650 containers per year (or 48 per day) transporting tree-killing insects might be entering the U.S. (My calculation of this estimate is explained in the blog on “risks of introduction” here.)
The
Haack study excluded imports from Mexico, Canada, and China. The first and
third countries have records of poor compliance with ISPM#15 requirements, so
the “approach rate” for all incoming shipments might well have been higher.
The
study of European imports focused on shipments of stone from China – which were
deliberately chosen to represent types of imports presenting a high risk of
transporting pests. Across Europe, over the four-year period, quarantine pests
were detected in 0.9% of the consignments – somewhat higher than the U.S.
number, as could be expected. However, there were large variations among participating
countries’ findings. Austria and France found 6.95% of consignments inspected
were infested, while half of European Union countries found none!
These differences demonstrate the importance of thorough inspections.
The data also indicate
that the problem is not decreasing. Austria detected pests in nearly one-fifth
(19.6%) of inspected shipments in 2016 – the final year of the study! However,
during that same year, only 1.5% of wood packaging lacked the ISPM#15 mark.
So How Should the
International Phytosanitary Community React to This Failure?
Data
cited in numerous studies indicate that ISPM#15 has probably succeeded in
reducing the presence of pests in wood packaging. This progress is good – but
insufficient. Our forests need further reductions.
In the meantime, however, the international standard has demonstrably failed to provide a secure method to evaluate the pest risk associated with wood packaging accompanying any particular shipment. The presence of the stamp on pieces of wood packaging does not reliably show that the wood is pest-free. Officials need to determine why. Is it fraud? That would mean deliberately placing the stamp on wood that had not been treated, which U.S. CBP staffers think is occurring (Harriger). The European Union audit team that visited China also thought they detected instances of fraud. They concluded that “the current system of official controls in China does not adequately ensure that SWPM which forms part of consignments of goods exported to the EU is marked and treated according to ISPM No. 15” (Eyre et al. 2018, p. 713). On the other hand, the US importers in Houston say they are pressing their European suppliers to provide pest-free dunnage.
What
more could we ask them to do to ensure that they are not receiving fraudulently
marked materials?
Perhaps
the problem has a different cause. Are the treatments themselves are less
effective than expected? One APHIS study found that twice as many larvae reared
from wood treated by methyl bromide fumigation survived to adulthood than
larvae reared from heat-treated wood; the reason is unclear (Nadel et al. 2016). Unfortunately, it is
apparently impractical to determine whether wood was heat treated by looking
for changes in the chemical profile of the wood (Eyre et al. 2018).
Nor
can we expect inspection of 100% of all risky consignments or detection of 100%
of quarantine pests in those consignments that are inspected. Therefore, the
European study authors concluded that inspection is best considered as a means
of gathering evidence of risk and a deterrent rather than a means of completely
preventing pest movement (Eyre et al.
2018).
The
European study authors called for review of ISPM#15 as a control system and to
investigate compliance at the source (Eyre et
al. 2018 p. 714).
What is APHIS
doing?
As I have noted previously – here and here – while U.S. CBP adopted a policy in 2017 under which it can penalize importers for each consignment not in compliance with ISPM#15, APHIS has not followed Custom’s lead on this. Instead, APHIS will apply a penalty only when an importer has accrued five violations over the period of a year. (The two agencies are acting under separate legal authorities.) This is yet another example of APHIS taking a less protective stance – as I described in earlier blogs.
Since
Customs is now applying the letter of the law, the most useful step would
probably be for APHIS (and the USDA Foreign Agriculture Service) to ramp up
efforts to assist U.S. importers which are trying to comply. The importers are
begging USDA to provide better information to them about foreign suppliers of wood
packaging and dunnage. Which have good vs.
poor records? USDA could also help importers trying to complain about specific
shipments to the exporting countries’ National Plant Protection Organizations
(NPPOs; departments of agriculture). In
addition, APHIS could augment its pressure on foreign NPPOs and the
International Plant Protection Convention more generally to ascertain the
reasons ISPM#15 is failing and to fix the problems.
APHIS has not been idle. The North American Plant Protection Organization (including Canada and Mexico) has sponsored two workshops intended to educate NPPOs and exporters in Asia and the Americas about the standard’s requirements. APHIS is planning to address wood packaging in an international symposium organized under the auspices of the International Year of Plant Health in July 2020 – I will provide details when they become available.
APHIS is collaborating with the Entomological Society of America to host a workshop on wood packaging at the ESA annual meeting in November 2020 – I will provide details when they become available. The Continental Dialogue on Non-Native Forest Insects and Diseases plans to link its annual 2020 meeting to this workshop.
More immediately, the Continental Dialogue on Non-Native Forest Insects and Diseases will have presentations on the wood packaging issue at its annual meeting in just 11 days! in Cleveland
In preparation for the 2020 meetings, APHIS should fund more studies and audits of wood packaging to document the current efficacy of the standard (that is, the pest approach rate); remember, Haack’s study relied on data which are now a decade old. Not only has time passed … Both the standard and U.S. enforcement policies have changed since 2009.
Significance of the
Wood Packaging Problems
The
apparent failure of the ISPM#15 standard to provide a reliable means to certify
treatment raises obvious issues regarding the risk of pest introductions.
However, the implications are much broader.
The premise of the international phytosanitary system – the Agreement on the Application of Sanitary and Phytosanitary Standards (SPS Agreement) and International Plant Protection Convention (IPPC) – is that importing countries should rely on exporting countries to take the actions necessary to meet the importing countries’ plant health goals. The ISPM#15 experience casts doubt on this premise. The exporters are not reliably ensuring the cleanliness of their wood packaging. Worse, wood packaging is easier to treat than fruits, vegetables, and living plants (plants for planting). The latter commodities are much more easily damaged or killed by treatments than are boards or even logs – which are, after all, already dead! (A longer discussion of the SPS Agreement and IPPC is found in Chapter III of Fading Forests II, available here.
I
hope that the international phytosanitary community will take advantage of the
heightened attention and effort associated with the International Year of Plant
Health in 2020 to re-examine all aspects of the current global phytosanitary system.
Posted by Faith Campbell
We
welcome comments that supplement or correct factual information, suggest new
approaches, or promote thoughtful consideration. We post comments that disagree
with us — but not those we judge to be not civil or inflammatory.
SOURCES
Eyre,
D., R. Macarthur, R.A. Haack, Y. Lu, and H. Krehan. 2018. Variation in
Inspection Efficacy by Member States of SWPM Entering EU. Journal of Economic
Entomology, 111(2), 2018, 707–715)
Nadel,
N., S. Myers, J. Molongoski, Y. Wu, S. Linafelter, A. Ray S. Krishnankutty, and
A. Taylor. 2016. Identificantion of Port Interceptions in Wood Packaging
Material: Cumulative Progress Report, April 2012 – August 2016
Fiscal
Year 2020 began on 1 October. Congress has not yet passed funding bills
(appropriations) for the full year. Agencies are operating now on a short-term
continuing resolution which expires on November 21st. Meanwhile,
representatives of the House and Senate will meet to reconcile the differences
between the two bodies’ appropriations bills in hope that a year-long bill can
be finalized by that time.
(Disagreement
between President Trump and the Congress about funding for the border wall
might prevent adoption of full-year appropriations bills and lead to another
government shutdown.)
I
report here the differences between House and Senate bills funding the USDA
APHIS and Forest Service programs that are vital to addressing non-native
forest pests.
APHIS
Over
the years, I have complained that inadequate funding is a major cause of
shortfalls in APHIS’ efforts to detect new invasions by tree-killing pests and to
respond to those invasions in effective ways.
While
funding levels are still too low, at least Congress is holding funding steady
for APHIS for Fiscal Year 2020 (which began three weeks ago, on October 1st).
Both House and Senate bills maintain funding for two crucial programs at the
FY19 levels:
“tree
and wood pests” program – $60 million (this matches the FY19 level; it is $4
million above the funding provided in previous years); and
“Pest
Detection” – $27.4 million.
The
House provided slightly higher funding than the Senate for two other programs:
“specialty
crops” (including sudden oak death) – $186.5 million in the House bill, $186
million in the Senate bill; and
“methods
development” – $21.686 million in the House bill, $20.686 million in the Senate
bill.
In the report accompanying its bill, the House called for two additional funding options to address emergencies. First, it set up a contingency fund of $470,000 to control outbreaks of insects, plant diseases, animal diseases and pest animals and birds to meet emergency conditions. Second, the report repeated language from past reports that authorizes the Secretary to take “such sums as may be deemed necessary” from other USDA programs in order to counter pest emergencies threatening any segment of U.S. agricultural production.
The Senate report addressed several high-profile tree pests. It called for complete eradication of the Asian longhorned beetle; mandated that APHIS report on its efforts to eradicate ALB and spotted lanternfly and to minimize spread of the polyphagous and Kuroshio shot hole borers; and to assist states that have recently detected the emerald ash borer. (This language is helpful, but it falls short of what I previously advocated – that APHIS continue efforts to prevent EAB spread, especially through movement of firewood.) The Senate report also urged APHIS to maintain FY19 level funding addressing the sudden oak death pathogen, in particular to improve understanding of the two strains of the pathogen present in Oregon’s forests link to blog to inform control and management techniques in wildlands. (Actually, management in wildlands falls largely to the Forest Service, with scientific input from both Agriculture Research Service and – to some extent – the NORS-DUC research nursery managed by APHIS.)
For a lengthier justification of my funding requests, see my earlier blog on APHIS funding
Funding for
Resistance Breeding through NIFA
As I pointed out in my blog in May, the 2018 Farm Bill included an amendment (Section 8708) that establishes a new priority for a grant program managed by the National Institute of Food and Agriculture. The amendment would support restoration to the forest of native tree species that have suffered severe levels of mortality caused by non-native insects, plant pathogens, or other pests. The amendment affects the Competitive Forestry, Natural Resources, and Environmental Grants Program under Section 1232(c)(2) of the Food, Agriculture, Conservation, and Trade Act of 1990 (16 U.S.C. 582A-8, as amended. However, this program has not been funded for more than a decade. In my blog, I asked you to support a $10 million appropriation to NIFA to fund a competitive grant program for such forests restoration.
Neither the House nor the Senate provided funding for
this program.
USFS
The House bill provides $277,155,000 for USFS Research and Development – nearly $20 million more than the Senate bill ($257,640,000). The House report links this increase to the recognition of the increasing risk to urban, rural, and wildland forests from insect and disease outbreaks and invasive plant infestations. The report calls on the Forest Service to develop a research program that addresses several priorities critical to forest health, including preventing the spread of disease and invasive species.
USFS engagement on pest issues with other federal agencies and state, local government, and private land managers is carried out through the Forest Health Management program under the State and Private Forestry division. The Senate bill and report are confusing because they have separated out salaries and other expenses. As a result, I can’t compare its figures to those in previous years or to those from the House. Partly for this reason, I urge you to support the House bill, which is quite clear in appropriating $103,736,000 for Forest Health Management, which is a programmatic increase of $19 million above the FY19 level and $29,919,000 above the budget request. I am encouraged by the House’ report, which encourages the Forest Service to address high priority invasive species, pests, and diseases, including the emerald ash borer and bark beetle infestations.
For longer explanations, see my earlier blog on USFS funding.
These bills show an increasing awareness of forest
pest issues in key funding committees in both the House and Senate. Let’s reinforce this message – and spread it
to the rest of Congress. Please contact your senators and representative and
ask them to support these funding levels.
Posted by Faith Campbell
We
welcome comments that supplement or correct factual information, suggest new
approaches, or promote thoughtful consideration. We post comments that disagree
with us — but not those we judge to be not civil or inflammatory.
It
is widely recognized that invasions of non-native species occur as a
consequence of international trade (see Seebens et. al. 2017 – full citations at the end of this blog). This is as
true for non-native forest pests as for any other bioinvader – see Aukema et al. 2010; Liebhold et al. 2012, Lovett et al. 2016. In fact, gross domestic product – as an indicator of levels
of trade — is a better predictor of the number of forest pest invasions in a
given country than the country’s amount of forested land (Roy et al. 2014).
shipping containers at port of Long Beach, California
As I noted in my previous blog, I began studying and writing about the threat to North America’s forests from non-native insects and pathogens in the early 1990s. I reported my analyses of the evolving threat in the three “Fading Forests” reports – coauthored by Scott Schlarbaum – in 1994, 2003, and 2014. These reports are available here.
I document here that both introduction
and spread of pests within the country have continued apace. While significant
efforts have been made to prevent introductions (described briefly under the
“Invasives 101” tab of the CISP website), they have fallen short. As I noted in
Fading Forests III, programs aimed at preventing spread of pests within the
country remain fragmented and often are unsuccessful.
The Challenge: Huge Volumes of goods are moving, providing
opportunities for pests
Since 1990, volumes of imported goods more than quintupled. Within the U.S., a total of 17,978 million tons of goods were transported in 2015; 10,776 million tons of this total by truck. About one-third of this total – 5,800 million tons – was moved farther than 250 miles. These vehicles moved on a public roads network of 4,154,727 miles (US DOT FFA). Consequently, once a pest enters the U.S., it can be moved quickly into every corner of the country.
Introductions
By and large,
establishment of tree-killing pests has occurred at a fairly steady rate of
about 2.5 per year, with “high-impact” insects and pathogens accumulating at
0.43 per year (Aukema et al. 2010). Since
introductions did not rise commensurately with rising import volumes, Lovett et al. (2016) concluded that the
recently adopted policies for preventing introductions referenced above are
having positive effects but are insufficient to reduce the influx of pests in
the face of ever-growing global trade volumes. The study’s authors went on to
say that absent more effective policies, they expect the continued increase in
trade will bring many new establishments of non-native forest pests.
One group of forest
pests did not enter at a steady rate, but rather entered at a higher rate since
1985 – wood-boring insects. Experts concluded that the increase probably
reflected increases in containerized shipping (Lovett et al. 2016). At the global level, the rate of fungal invasions has
also recently been reported to be increasing rapidly (Roy et al. 2014).
Asian longhorned beetle
Geography of trade
patterns also matters. Opening of trade with China (in 1979) offered
opportunities for pests from a new source country which has a similar climate
and biology. Roy et al. describe the importance of phylogenetic
relatedness of pests and of tree hosts in explaining tree species’ vulnerability
to introduced pests. The most vulnerable forests are those made up of species
similar to those growing in the source of the traded goods – i.e., the temperate forests of the
northeastern U.S. – when goods are imported from similar forested areas of
Europe and Asia. Chinese-origin wood-boring pests began to be detected around
1990. This already short interval probably underestimates how quickly pests
began arriving; detection methods were poor in those years, so a pest was often
present for close to a decade before detection.
Between 1980 and 2016, at least 30 non-native species of wood- or bark-boring insects in the Scolytinae / Scolytidae were newly detected in the United States (Haack and Rabaglia 2013; Rabaglia et al. 2019). Over the same period, approximately 20 additional tree pests were introduced to the continental states (Wu et al. 2017; Digirolomo et al. 2019; R. Haack, pers. comm.) plus about seven to America’s Pacific islands. Not all of the new species are highly damaging, but enough are. See my previous blog here.
Many of the tree-killing
pests were probably associated with pathways other than wood packaging. These
include 6 of the 7 Agrilus species, sudden oak death pathogen, three pests of palm trees, the
spotted lanternfly, beech leaf disease; and the pests introduced to America’s
Pacific Islands.
HIGH-RISK
PATHWAYS OF INTRODUCTION
Already
in the 1990’s it was evident that better preventing pest introductions would
depend on shutting down the variety of pathways by which they move around the
world. At that time, attention focused on imports of
logs and nursery stock (nursery stock makes up one component of a broader
category called by phytosanitary agencies “plants for planting”). Both logs and
“plants for planting” had well-established histories of transporting pests and
import volumes were expected to grow. We have since learned that there are many
more pathways!
Plants for Planting
Imports of “plants for planting” (phytosanitary agencies’ term, which encompasses nursery stock, roots, bulbs, seeds, and other plant parts that can be planted) have long been recognized as a dangerous pathway for introduction of forest pests. For example, this risk was the rationale for adopting the 1912 Plant Quarantine Act. Charles Marlatt, Chairman of USDA’s Federal Horticultural Board (see “Then and Now” in Fading Forests III here), wrote about the risk in National Geographic in April 1911 (urging adoption of the 1912 law) and again in August 1921. See also Brasier (2008), Roy et al. (2014), Liebhold et al. (2012), Jung et al. (2016).
Japanese cherry trees being burned because of scale infestation January 28, 1910; Agriculture Research Service
Of the 91 most
damaging non-native forest pest species in the U.S. (Guo et al. 2019), about 62% are thought to have entered North America
with imports of live plants. These include nearly all the sap-feeding insects,
almost 90% of the foliage-feeding insects, and approximately half of the
pathogens introduced during the period 1860-2006 (Liebhold et al. 2012). Specific examples include chestnut blight, white pine
blister rust, Port-Orford-cedar root disease, balsam woolly adelgid, hemlock
woolly adelgid, beech scale, butternut canker, dogwood anthracnose, and sudden
oak death. In more recent years, introductions via this pathway possibly
include ‘ōhi‘a
rust, rapid ‘ōhi‘a death pathogens, and beech leaf disease. The gypsy
moth, while a foliage feeder, was not introduced via imports of live plants.
The
APHIS annual report for 2018 reported that in that year we imported 18,502
shipments containing more than 1.7 billion
plant units (plants, bulbs, in vitro materials, etc.).
Liebhold et al. 2012, relying on 2009 data, found that about 12 percent of incoming plant shipments had symptoms of pests – a rate more than 100 times greater than that for wood packaging. Worse, a high percentage of the pests associated with a shipment of plants is not detected by the federal inspectors. The meaning of this finding is unclear because the study did not include any plant genera native to temperate North America and APHIS points out that infestation rates varied considerably among genera in the study. However, APHIS has not conducted its own analysis to document the “slippage rate” on imports of greatest concern to forest conservationists, i.e., imports of woody plants. I provide details on pests detected on imports of woody plants in recent in my blog here.
Clearly the risk of pest introductions continued at least until recently. I reviewed an APHIS database listing pests newly detected in the country during the period 2009-2013. I concluded that approximately 37 of the 90 “new” pests listed in the database (viruses, fungi, aphids and scales, whiteflies, mites) were probably introduced via imports of plants, cuttings, or cut foliage or flowers. I discussed these matters in greater detail here.
Adoption of a new regulatory regime governing imported plants for planting (Q-37 regulation) in 2018 is too recent to for us to see its impact. But the new regulation sets up a process under which APHIS can impose more protective regulations on specific types of plants or plants from certain countries of origin to counter a perceived concerning level of risk. Until APHIS begins activating its new powers by negotiating more protective regulations governing plant imports from high-risk sources, it seems unlikely there will be any meaningful change in the introduction rates.
Crates, Pallets,
and Other Forms of wood packaging (solid wood packaging, or SWPM)
Recognition
of the risk associated with wood packaging is much more recent. In 1982, a USDA
risk assessment concluded that the wood boring insects found in crates and
pallets were not of great concern (USDA APHIS and Forest Service, 2000).
However, contradictory indications were quickly documented – including from
APHIS’ own port interception data – which the agency began collecting in 1985. Over
the 16-year period 1985-2000, 72%
of
the 6,825 bark beetles (Scolytidae)
intercepted by APHIS were found on SWPM (Haack 2002). Cerambycids (longhorned
beetles) and buprestids (jewel beetles) make up nearly 30% of insects detected
in wood packaging over the last 30 years (Haack et al. 2014).
Detection
of outbreaks of the Asian longhorned beetle and other woodborers in the
mid-1990s made it clear that wood packaging was, indeed, a high-risk pathway.
Of
the 91 most damaging non-native pest species in the US, 30% probably arrived
with wood packaging material or other wood products (Liebhold et al. 2012). This group includes many
of the most damaging pests, the deadly woodborers – Asian longhorned beetle,
emerald ash borer, redbay ambrosia beetle,
possibly the polyphagous and Kuroshio shot hole borers.
CBP agents inspecting a pallet
As noted above, introductions of wood borers have risen in recent decades, widely accepted as associated with the rapid increase in containerized shipping after 1980. In 2009 it was estimated that 75% of maritime shipments were packaged in crates or pallets made of wood (Meissner et al. 2009). A good history of the global adoption of containerized shipping is Levinson, M. The Box: How the Shipping Container Made the World Smaller and the World Economy Bigger (Princeton University Press 2008)
The simultaneous
opening of trade with China (in 1979) offered opportunities for pests from a
new source country which has a similar climate and biology. Chinese-origin wood-boring
pests began to be detected around 1990. This already short interval probably underestimates
how quickly pests began arriving; detection methods were poor in those years,
so a pest was often present for close to a decade before detection.
I have already documented numerous times that, despite the U.S.’ implementation of the International Standard of Phytosanitary Measures (ISPM) #15 in 2006, live quarantine pest woodborers continue to enter the U.S. in wood packaging. The best estimate is that 0.1% of wood packaging entering the United States is infested with wood-borers considered to be quarantine pests (Haack et al. 2014). More than 22 million shipping containers entered the U.S. via maritime trade in 2017 (US DoT). As noted, an estimated 75% of sea-borne containers include wood packaging. Applying the 0.1% estimate to these figures results in an estimate that as many as 17,650 containers per year (or 48 per day) transporting tree-killing insects enter the U.S.
Over a period of
nine years – Fiscal Years 2010 through 2018 – U.S. Customs and Border
Protection (CBP) detected more than 28,600 shipments with wood packaging that
did not comply with ISPM#15 (Harriger presentations to the annual meetings of
the Continental Dialogue on Non-Native Forest Insects and Diseases). While most
of the non-compliant shipments were wood packaging that lacked the required
mark showing treatment per ISPM#15,
in 9,500 cases the wood packaging actually harbored a pest in a regulated
taxonomic group.
Disturbingly, 97%
of the shipments that U.S. CBP found with infested wood packaging bear the
ISPM#15 mark certifying that wood had been fumigated or heat-treated (Harriger
2017). CBP inspectors tend to blame this on widespread fraud in use of the mark.
On the other hand, one study found that larvae can survive both treatments –
although the frequency of survival was not determined. It was documented that twice
as many larvae reared from wood treated by methyl bromide fumigation survived
to adulthood than larvae reared from heat-treated wood; the reason is unclear
(Nadel et al. 2016).
The APHIS’ record
of interceptions for the period FYs 2011 – 2016 contained 2,547 records for
insect detections on wood packaging. The insects belonged to more than 20
families. Families with the highest numbers of detections were Cerambycids –
25% of total; Curculionidae – 23% (includes Dendroctonus,
Ips, Orthotomicus, Scolytinae, Xyleborus, Euwallacea); Scolytidae – 17% (includes
true weevils such as elm bark beetles); Buprestids – 11%; and Bostrichidae –
3%. Not all of the insects in these groups pose a threat to North American
plant species.
One encouraging data point is that since 2010, there have been no detections of species of bark and ambrosia beetles new to North America in the traps deployed by the USDA Forest Service Early Detection and Rapid Response program (Rabaglia 2019). The 2014 recognition of the Kuroshio shothole borer apparently did not result from this trapping program.
There have been several changes in the wood packaging standard and its implementation by CBP since 2009, the year Haack et al. 2014 analyzed the “pest approach rate”. APHIS has not carried out a study to determine whether these recent changes have reduced the approach rate below Haack’s estimate of 0.01%. Consequently, we do not know whether these changes have reduced the risk of pest introductions.
Other Pathways That
Transport Fewer Pests – Some of Which Have High Impacts
Insects
that attach egg masses to hard surfaces can be transported by ship
superstructures, containers, and hardsided cargoes such as cars, steel beams,
and stone. While relatively few species have been moved in this way, some have
serious impacts. The principal examples are the gypsy moths from Asia, which
feed on 500 species of plants (Gibbon 1992).
The United States and Canada have a joint program – under the auspices of the North American Plant Protection Organization (see RSPM #33) aimed at preventing introduction of species of Asian gypsy moths. The NAPPO standard originally went into force in March 2012. Under its terms, ships leaving ports in those countries during gypsy moth flight season must be inspected and cleaned before starting their voyage.
Gypsy moth populations rise and fall periodically; it is much more likely that egg masses will be attached to ships during years of high moth population densities. These variations are seen in U.S. and Canadian detection reports – as reported here.
While most AGM detections are at West Coast ports, [here; and here] the risk is not limited to that region. AGM have been detected at Wilmington, NC; Baltimore, MD; Charleston, SC; Savanna and Brunswick, GA; Jacksonville, FL; New Orleans, LA; Houston and Corpus Christi, TX; and even McAlester, OK.
Nor is the risk limited to the ships themselves. In 2014, more than 500 Asian gypsy moth egg masses were found on four shipments of imported steel slabs arriving at ports on the Columbia River in Washington.
Between 1991 and 2014, AGM was detected and eradicated
on at least 20 occasions in locations across the United States (USDA AGM pest
alert). Additional outbreaks have been discovered and eradication efforts
undertaken in more recent years.
A second example is
the spotted lanternfly (SLF) (Lycorma delicatula), which was first
detected in southeast Pennsylvania in autumn 2014. It is native to Asia; it is
believed to have entered the country as egg masses on imported stone.
While SLF is
clearly a pest of agriculture – especially grapes and tree fruits – its
importance as a forest pest is still unclear. Many native forest trees appear
to be hosts during the insect’s early stages, including maples, birches,
hickories, dogwoods, beech, ash, walnuts, tulip tree, tupelo, sycamore, poplar,
oaks, willows, sassafras, basswood, and elms. Adult lanternflies strongly
prefer the widespread invasive species tree of heaven (Ailanthus altissima).
As of August 2019, SLF was established in parts of five states: Delaware, Maryland, New Jersey, Pennsylvania, and Virginia. It was detected as having spread to a 14th county in Pennsylvania; five new counties in New Jersey. APHIS is working with state departments of Agriculture in these states, as well as supporting surveys in New York, North Carolina, and West Virginia (USDA APHIS DA-2019-20, August 7, 2019). Apparently the detections of a few adults – alive or dead – in Connecticut and New York had not evolved into an outbreak. See description and map here.
Imports of logs – roundwood – seem inherently risky. Certainly Dutch elm disease was introduced via this pathway. However, there have been few pest introductions linked to this pathway in recent years, probably because we import most of our unprocessed lumber from Canada. (I provide considerable data on U.S. roundwood imports in Fading Forests III here.)
Decorative items and furniture made of unprocessed wood certainly have the potential to transport significant pests (USDA APHIS 2007). Examples include boxes and baskets; wood carvings; birdhouses; artificial Christmas trees or other plants; trellises; lawn furniture. To date, apparently, no high-impact pest has been introduced via this pathway, although pests intercepted on shipments have included Cerambycids from Asia, e.g., velvet longhorned beetle and here.
Alarmed by high numbers of infested shipments from China, APHIS first suspended imports of such items temporarily; then adopted a regulation (finalized in March 2012 – USDA APHIS 2012).
APHIS
has not taken action to prevent introductions on such items imported from other
countries – although the North American Plant Protection Action adopted a
regional standard making the case for such action and outlining a risk-based
approach (NAPPO RSPM#38).
Snails on Shipping
Containers
Snails have been
detected on shipping containers and wood packaging for decades. In 2015, APHIS
stepped up its efforts to address this risk through bilateral negotiations with
Italy and launching regional and international efforts to develop guidance for
ensuring pest-free status of shipping containers (Wendy Beltz, APHIS, presentation
to National Plant Board, 2018 annual meeting).
SPREAD
WITHIN THE UNITED STATES
Major pathways for human-assisted spread of pests within the country are sales of plants for planting, movement of unprocessed wood – especially firewood, and hitchhiking on transport vehicles. Since most forest pests are not subject to federal quarantine, any regulatory programs aimed at preventing spread depend on cooperation among the 50 states. None of these pathways is regulated adequately to prevent pests’ spread. See Chapter 5 of Fading Forests III here.
And since neither
federal nor state agencies do significant enforcement of existing regulations,
preventing spread often depends upon pest awareness of, and voluntary
compliance by, individuals and companies.
Even pests subject to a federal quarantine are not prevented from spreading. Plants exposed to the sudden oak death pathogen were shipped to 18 states in spring 2019.
SOD-infected rhododendron plant; Indiana Department of Natural Resources
A collaborative effort by the nursery industry, APHIS, and states (Systems Approach to Nursery Certification, or SANC) is striving to close gaps linked to the standard practice of inspecting plants at the time of shipping, but full implementation of this voluntary program is still years away.
Transport of firewood has been responsible for movement of pests both short distances, e.g., goldspotted oak borer in southern California; and long distances – e.g., emerald ash borer to Colorado. APHIS attempted to develop a certification program but the industry was unable to put one together (see Chapter 5 of Fading Forests III). Current federal and state regulations of firewood are tied to the emerald ash borer quarantine, which APHIS has proposed to terminate. Wood for turning and woodworking has also been linked to movement of pests, e.g., walnut twig beetle/thousand cankers disease from the west to Pennsylvania.
emerald ash borer
Truck transport of a
variety of goods has transported European gypsy moths from the infested areas
in the east to the west coast. Transport of stone probably moved spotted
lanternfly from southeastern Pennsylvania to Winchester, Virginia.
SOURCES
Aukema, J.E., D.G. McCullough, B. Von
Holle, A.M. Liebhold, K. Britton, & S.J. Frankel. 2010. Historical
Accumulation of Nonindigenous Forest Pests in the Continental United States.
Bioscience. December 2010 / Vol. 60
No. 11
Brasier, C.M. 2008. The biosecurity
threat to the UK and global environment from international trade in plants. Plant Pathology (2008) 57, 792-808
Bray, A.M., L.S. Bauer, T.M. Poland,
R.A. Haack, A.I. Cognato, J.J. Smith. 2011. Genetic analysis of emerald ash
borer (Agrilus planipennis Fairmaire)
populations in Asia and North America. Biol. Invasions (2011) 13:2869-2887
Gibbon,
A. 1992. “Asian Gypsy Moth Jumps Ship to United States.” Science.
Vol. 235. January 31, 1992.
Haack R. A. and J.F. Cavey. 1997.
Insects Intercepted on Wood Articles at United States Ports-of-Entry and Two
Recent Introductions: Anoplophora
glabripennis and Tomicus piniperda.
In press in International forest insect workshop proceedings, 18 – 21
August 1997, Pucon, Chile. Corporacion National Forestal, Santiago, Chile.
Haack, R.A., F. Herard, J. Sun, J.J.
Turgeon. 2010. Managing Invasive Populations of Asian Longhorned Beetle and
Citrus Longhorned Beetle:A Worldwide Perspective. Annu. Rev. Entomol. 2010.
55:521-46.
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R.A. and R.J. Rabaglia. 2013. Exotic Bark and Ambrosia Beetles in the USA:
Potential and Current Invaders. CAB International 2013. Potential Invasive
Pests of Agricultural Crops (ed. J. Peña)
Haack R.A., Britton K.O., Brockerhoff, E.G., Cavey, J.F.,
Garrett., L.J., 2014. Effectiveness of the International Phytosanitary Standard
ISPM No. 15 on Reducing Wood Borer Infestation Rates in Wood Packaging Material
Entering the United States. PLoS ONE 9(5): e96611.
doi:10.1371/journal.pone.0096611
Haack,
R.A., F. H´erard, J. Sun, and J.J. Turgeon. 2010. Managing Invasive Populations
of Asian Longhorned Beetle and Citrus Longhorned Beetle: A Worldwide
Perspective. Annu. Rev. Entomol. 2010. 55:521–46
Harriger, K. Department of Homeland Security Bureau of
Customs and Border Protection, presentation to the Continental Dialogue on
Non-Native Forest Insects and Diseases, November 2017.
Jung T, Orlikowski L, Henricot B, et al. 2016. Widespread
Phytophthora infestations in European nurseries put forest, semi-natural and
horticultural ecosystems at high risk of Phytophthora diseases. Forest
Pathology 46: 134–163.
Liebhold, A.M., E.G. Brockerhoff, L.J. Garrett, J.L.Parke, and K.O Britton.
2012. Live plant inports: the major pathway for forest insect and pathogen invasions of the US. Frontiers in
Ecology.
Lovett, G.M., M. Weiss, A.M. Liebhold, T.P. Holmes, B.
Leung, K.F. Lambert, D.A. Orwig, F.T.
Campbell, J. Rosenthal, D.G. McCullough, R. Wildova, M.P. Ayers, C.D. Canham,
D.R. Foster, S.L. LaDeau, and T. Weldy. 2016.
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Applications, 26(5) pp. 1437-1455.
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Ferguson, and L. Newton. 2009. EVALUATION OF PATHWAYS FOR EXOTIC PLANT PEST
MOVEMENT INTO AND WITHIN THE GREATER CARIBBEAN REGION. Caribbean Invasive
Species Working Group (CISWG) and Plant Epidemiology and Risk Analysis
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Meeting, March 12 – 14, 2019, West
Chester, Pennsylvania
Nadel, N., S. Myers, J. Molongoski, Y.
Wu, S. Linafelter, A. Ray S. Krishnankutty, and A. Taylor. 2016.
Identificantion of Port Interceptions in Wood Packaging Material: Cumulative
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Rabaglia,
R.J., A.I. Cognato, E. R. Hoebeke, C.W. Johnson, J.R. LaBonte, M.E. Carter, and
J.J. Vlach. 2019. Early Detection and Rapid Response. A Ten-Year Summary of the
USDA Forest Service Program of Surveillance for Non-Native Bark and Ambrosia
Beetles. American Entomologist Volume 65, Number 1
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F.T. Campbell, J.J. Burdon, R. Sniezko, and C. Brasier. 2014. Frontiers in Ecology 12(8): 457-465
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importation into the United States. Revision 6. July.
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China. Final rule. Federal Register 77(41):
12437-12444. March 1. Online at http://www.gpo.gov/fdsys/pkg/FR-2012-03-01/pdf/2012-4962.pdf.
Accessed August 2, 2013.
United
States Department of Transportation Bureau of Transportation Statistics Freight
Facts and Figures
United States Department of Transportation, Maritime
Administration, U.S. Waterborne Foreign Container Trade by U.S. Customs Ports
(2000 – 2017) Imports in Twenty-Foot Equivalent Units (TEUs) – Loaded
Containers Only
Williams, L.H. and J.P. La Fage. 1979.
Quarantine of Insects Infesting Wood in International Commerce. in J.A.
Rudinksy, ed. Forest Insect Survey and Control Fourth Edition 1979
Wu,Y.,
N.F. Trepanowski, J.J. Molongoski, P.F. Reagel, S.W. Lingafelter, H. Nadel1,
S.W. Myers & A.M. Ray. 2017. Identification of wood-boring beetles
(Cerambycidae and Buprestidae) intercepted in trade-associated solid wood
packaging material using DNA barcoding and morphology Scientific Reports 7:40316
dead whitebark pine in Crater Lake National Park photo by F.T. Campbell
I began studying and writing about the threat to North America’s forests from non-native insects and pathogens in the early 1990s – nearly 30 years ago. I reported my analyses of the evolving threat in the three “Fading Forests” reports – coauthored by Scott Schlarbaum – in 1994, 2003, and 2014. These reports are available here.
So what has changed over those 30 years? What remains the same? Why have both the changes and the stasis occurred? What can we do to fix the gaps, close unaddressed pathways, strengthen flabby policies? I will address these issues in this and following blogs.
experimental American chestnut planted in Fairfax County, VA photo by F.T. Campbell
What has changed
since the early 1990s:
Adoption and implementation of significant new international and national regulations and programs aimed at preventing introductions of non-native invasive species.
Despite the welter of new regulations, an alarming increase in numbers of highly damaging forest pests established in the country. (By my count, about 50 new species have established on the continent, six on Pacific islands; see details below.)
Alarming spread of established pests to new geographic regions and new hosts (e.g., emerald ash borer in 35 states and 5 provinces; laurel wilt disease across the range of redbay and swamp bay; rapid ‘ōhi‘a death on three of the main Hawaiian islands).
Introductions via unexpected pathways and vectors far removed from phytosanitary agencies’ usual targets, e.g., ship superstructures, imported steel and stone …
What has remained the
same since the early 1990s:
Inadequate
resources provided to response and recovery efforts.
Available
funding focused on only a few of the more than 90 species causing damage.
Adoption
of insufficiently protective regulations that have failed to prevent
introduction and spread of tree-killing pests.
Lengthy
delays in implementing programs that tighten controls – another factor in
continuing introductions and spread.
Continued
importance of expected pathways – nursery stock and raw wood, especially
crates, pallets, and other forms of wood packaging.
Federal
and state agencies still choose not to take action on pests e.g., goldspotted oak borer, polyphagous
and Kuroshio shothole borers, beech leaf disease.
Inadequate
coordination despite several efforts to set priorities.
Spurts
of attention by media and political decision-makers, contrasted by lengthy
periods of inattention.
Failure
of most stakeholders to support efforts to prevent and respond to introductions
of tree-killing pests.
Details: The Situations
Then and Now
(Many of the individual species mentioned here are described more fully here. Full citations of sources are at the end of blog.)
American elm on the National Mall, Washington, D.C.
photo by USDA Agricultural Research Service
In 1993:
The number of non-native forest pest species established in the U.S. was estimated at between 300 (Millers et al. 1993) and 380 (Mattson et al., 1994; Liebhold et al., 1995) .
The area suffering the greatest numbers and impacts was the Northeast.
Several highly damaging pests that had been established for decades, including chestnut blight, white pine blister rust, Port-Orford-cedar root disease, Dutch elm disease, hemlock woolly adelgid, butternut canker, and dogwood anthracnose were receiving some attention but continued to spread.
USDA Forest Service funding for management of exotic pest infestations was crisis-oriented, with “… priorities … set under political pressures for immediate answers, with too much regard for short-term problems and too little consideration for broader management objectives.” (NAS 1975)
Since few high-profile pests had been introduced in recent years, APHIS was not actively engaged. In FY92, APHIS spent $20 million on efforts to eradicate the Asian gypsy moth. The narrow focus is illustrated by the fact that in FY93, more than two-thirds of all USDA tree pest control funds were devoted to efforts to suppress or eradicate the European gypsy moth (See FFI).
Concern about possible new introductions had grown; it focused on proposals to import unprocessed wood from Siberia, New Zealand, and Chile. The USDA Forest Service, academic scientists, and therefore APHIS emphasized the risks of known Asian pests, e.g., Asian gypsy moth, to western coniferous forests (See FFI). While individual scientists had expressed concern about wood packaging material, there was little public discussion of this threat.
We would learn later that several of the most damaging pests were already present in the country but not yet recognized – Asian longhorned beetle, sudden oak death pathogen, probably emerald ash borer.
beech leaf disease
photo by John Pogacnik
In 2019:
Numbers of non-native insects and pathogens attacking trees in North America approach 500 species. (In Fading Forests III, I calculated that by the first decade of the 21st Century, the number had risen to at least 475. Several more have been detected since 2014. More than 181 exotic insects that feed on woody plants had established in Canada. (Source: USDA APHIS. 2000. Wood packaging risk assessment.)
Of these, 91 are considered “serious” threats (Guo et al. 2019). This estimate excludes pests native to portions of North America that are causing severe damage in naïve hosts – e.g., goldspotted oak borer; pests of palms; and pests attacking trees on U.S. Pacific and Caribbean islands.
Introductions had continued.
Between 1980 and 2016, at least 30 non-native species of wood- or bark-boring insects (Scolytinae / Scolytidae) were newly detected in the U.S. (Haack and Rabaglia 2013; Rabaglia et al. 2019). A few of these are highly damaging, e.g. redbay ambrosia beetle, polyphagous and Kuroshio shothole borers.
In addition to these 30 new pests, other highly damaging tree-killing pests probably introduced since the 1980s include (on the continent):
Eight Cerambycids such as Asian longhorned beetle (Wu et al. 2017)
7 Agrilus, including emerald ash borer and soapberry borer; plus goldspotted oak borer transported from Arizona to California (Digirolomo et al. 2019; R. Haack, pers. comm.)
Sirex woodwasp
Pests of palm trees, e.g., red palm mite, red palm weevil, South American palm weevil
Spotted lanternfly
Beech leaf disease
Also not included in the above estimate and lists are tree-killing pests on America’s Pacific Islands :
‘ōhi‘a rust
Cycad scale
Cycad blue betterfly
Erythrina gall wasp
two Ceratocystis pathogens that cause rapid ‘ōhi‘a death
Coconut rhinoceros beetle
Authorities also carried out approximately 25 eradication programs targetting introductions of the Asian gypsy moth (USDA Pest Alert Asian Gypsy Moth plus additional outbreaks since 2014).
Impacts of exacerbated tree mortality rates linked to these introduced pests are seen across wide swaths of the country, and affect widespread species, genera, and families.
dead redbay in Claxton, Georgia photo by Scott Cameron
I will discuss the risk of continuing new introductions in a separate blog.
Trying to Develop
the Big Picture and Set Priorities
In
recent years, USDA Forest Service scientists have made several attempts to
provide nation-wide assessments of the impact of these pests and criteria for
establishing priorities.
The
National Insect and Disease Forest Risk Assessment predicted the loss of basal
area to various pests over the 15-year time period 2012 – 2027. The assessment
predicted the following losses for specific species: 90% for redbay; 60% for whitebark
pine; more than 40% for limber pine; 24% for tanoak; 11% for coast live oak; 6%
for eastern and Carolina hemlock; 27% for eight species of ash; 20% for
American elm; 19% for red oak; 18% for American beech (Krist et al. 2014).
A separate group of scientists found that, nation-wide, non-native forest pests are causing an approximate 5% increase in total mortality by tree volume (Randy Morin at NEFPC). For details on Dr. Morin’s findings, see my blog here.
A third approach to developing a nation-wide picture, Project CAPTURE, (and my blog here) utilized FIA data to develop priorities for conservation action. Fifteen species were placed in the highest priority category, including Florida torreya (Torreya taxifolia), American chestnut and Allegheny and Ozark chinquapins, redbay, five species of ash, two species of hemlock, Port-Orford cedar, tanoak, and butternut (Potter et al. 2019(b).
According
to Project CAPTURE, the non-native pests affecting the largest number of hosts
are the European gypsy moth, which attacks 65 hosts; and oak wilt (Bretziella fagacearum), which infects 61
hosts. The Asian longhorned beetle attacks 43 hosts (Potter et al. 2019(b).
I note that several other non-native pests also have high numbers of host species. In the Project CAPTURE study, these pests are ranked lower because the project limited its evaluation to the five agents with the greatest effect on any particular host. Thus, of the 18 native tree species that host one or both of the invasive shothole borers and associated Fusarium disease complex (PSHB website), the project included only six. Of the 22 tree species listed by APHIS as hosts of Phytophtora ramorum, the project included 12 (K. Potter, pers. comm. April 17, 2019).
SOD-killed tanoak on the Big Sur peninsula, California photo by Matteo Garbelotto, University of California Berkeley
More extensive discussions of
non-native pests’ impacts are provided in Lovett et al. 2006, Lovett et al.
2016, and Potter et al. 2019. A
book-length discussion of invasive species impacts – ranging from feral hogs to
invasive plants, is expected in December; look for Poland et al. (in press).
SOURCES
Aukema,
J.E., D.G. McCullough, B. Von Holle, A.M. Liebhold, K. Britton, & S.J.
Frankel. 2010. Historical Accumulation of Nonindigenous Forest Pests in the
Continental United States. Bioscience. December
2010 / Vol. 60 No. 11
Digirolomo, M.F., E. Jendek, V.V. Grebennikov, O. Nakladal. 2019. First North American
record of an unnamed West Palaearctic Agrilus (Coleoptera:
Buprestidae) infesting European beech (Fagus sylvatica) in New York
City, USA. European Journal of
Entomology. Eur. J.
Entomol. 116: 244-252, 2019
Guo,
Q., S. Fei, K.M. Potter, A.M. Liebhold, and J. Wenf. 2019. Tree diversity
regulates forest pest invasion. Proceedings of the National Academy of Sciences
of the United States of America. www.pnas.org/cgi/doi/10.1073/pnas.1821039116
Haack,
R.A. and R.J. Rabaglia. 2013. Exotic Bark and Ambrosia Beetles in the USA:
Potential and Current Invaders. CAB International 2013. Potential Invasive
Pests of Agricultural Crops (ed. J. Peña)
Krist,
F.J. Jr., J.R. Ellenwood, M.E. Woods, A. J. McMahan, J.P. Cowardin, D.E. Ryerson,
F.J. Sapio, M.O. Zweifler, S.A. Romero 2014. National Insect and Disease Forest
Risk Assessment. United States Department of Agriculture Forest Service Forest
Health Technology Enterprise Team FHTET-14-01
Leung,
B., M.R. Springborn, J.A. Turner, E.G. Brockerhoff. 2014. Pathway-level risk
analysis: the net present value of an invasive species policy in the US. The
Ecological Society of America. Frontiers of Ecology.org
Liebhold, A. M., W. L. MacDonald, D. Bergdahl, and V. C. Mastro. 1995. Invasion by exotic forest pests: a threat to forest ecosystems. Forest Sci., Monograph 30. 49 pp.
Lovett,
G.M., C.D. Canham, M.A. Arthur, K.C. Weathers, and R.D. Fitzhugh. Forest
Ecosystem Responses to Exotic Pests and Pathogens in Eastern North America. BioScience
Vol. 56 No. 5 (May 2006)
Lovett,
G.M., M. Weiss, A.M. Liebhold, T.P. Holmes,
B. Leung, K.F. Lambert, D.A. Orwig, F.T. Campbell, J. Rosenthal, D.G.
McCullough, R. Wildova, M.P. Ayres, C.D. Canham, D.R. Foster, SL. Ladeau, and
T. Weldy. 2016. NIS forest insects and pathogens in the US: Impacts and policy
options. Ecological Applications, 26(5), 2016, pp. 1437–1455
Mattson,
W. J., P. Niemela, I. Millers, and Y. Ingauazo.
1994. Immigrant phytophagous insects on woody plants in the United
States and Canada: an annotated list.
USDA For. Ser. Gen. Tech. Rep. NC-169, 27 pp.
Millers, I. United States
Department of Agriculture, Forest Service Entomologist, Forest Health
Protection Northeastern Area State and Private Forestry. Durham, NH. Personal
communication to F.T. Campbell, 1993.
Morin, R. presentation at Northeastern Forest Pest Council 81st Annual
Meeting, March 12 – 14, 2019, West
Chester, Pennsylvania
National Academy of Sciences. 1975. Forest Pest Control. Washington, D.C.
Poland,
T.M., Patel-Weynand, T., Finch, D., Miniat, C. F., and Lopez, V. (Eds) (2019),
Invasive Species in Forests and Grasslands of the United States: A
Comprehensive Science Synthesis for the United States Forest Sector. Springer Verlag. (in press).
Potter,
K.M., M.E. Escanferla, R.M. Jetton, and G. Man. 2019. Important Insect and
Disease Threats to US Tree Species and Geographic Patterns of Their Potential
Impacts. Forests 2019, 10, 304.
Potter,
K.M., Escanferla, M.E., Jetton, R.M., Man, G., Crane, B.S. 2019. Prioritizing
the conservation needs of US tree spp: Evaluating vulnerability to forest insect
and disease threats, Global Ecology and Conservation (2019), doi:
https://doi.org/10.1016/
Rabaglia,
R.J., A.I. Cognato, E. R. Hoebeke, C.W. Johnson, J.R. LaBonte, M.E. Carter, and
J.J. Vlach. 2019. Early Detection and Rapid Response. A Ten-Year Summary of the
USDA Forest Service Program of Surveillance for Non-Native Bark and Ambrosia
Beetles. American Entomologist Volume 65, Number 1
U.S.
Department of Agriculture, Animal and Plant Health Inspection Service. 2009.
Risk analysis for the movement of wood packaging material (WPM) from
Canada into the US.
Wu,Y.,
N.F. Trepanowski, J.J. Molongoski, P.F. Reagel, S.W. Lingafelter, H. Nadel1,
S.W. Myers & A.M. Ray. 2017. Identification of wood-boring beetles
(Cerambycidae and Buprestidae) intercepted in trade-associated solid wood
packaging material using DNA barcoding and morphology Scientific Reports 7:40316
As indicated by Strategic Plans and Annual Reports
APHIS HQ in Riverside Maryland
In recent months, APHIS has released its 2019–2023 Strategic Plan and its 2018 annual report – which outlines how well the agency is doing in achieving goals from the 2015-2018 Strategic Plan. There is lots of information in these documents – but it is often presented in ways that make understanding it difficult. Still, I will attempt to compare the APHIS’ 2015 Strategic Plan and the 2019 Plan as well as review recent annual reports to see what priorities APHIS has set and how well it is realizing them.
APHIS’ Mission
According
to the APHIS website, the agency’s mission is to safeguard U.S. agricultural
and natural resources against the entry, establishment, and spread of
economically and environmentally significant pests and to facilitate the safe
trade of agricultural products.
The 2019 Plan shortened this Mission: To
safeguard the health, welfare, and value of American agriculture and natural
resources.
The 2019 Plan links the Mission tightly to U.S. Department of Agriculture priorities, e.g., honesty and integrity, commitment, accountability, reliability, and responsible stewardship of taxpayer resources. There follow promises to deliver services with a customer focus, efficiency and responsiveness, and ensuring that phytosanitary protection is at a reasonable cost. There is great emphasis in the 2019 plan on understanding how agricultural businesses operate, collaborating with partners, and seeking alternatives to regulation.
USDA Secretary Sonny Perdue
Goals
The
2019 Strategic Plan also amends the agency’s goals – they are much more
general, less specific. The new goals emphasize program efficiency, collaborative
approaches, and empowering employees. Perhaps these changes were made because
the 2019 Plan covers the entire agency while the earlier (2015) Plan guided
only Plant Protection and Quarantine (PPQ. However, I fear that the new goals
reflect a much greater emphasis on non-regulatory approaches.
Contrasting
Goals
The
2015 Strategic Plan’s three goals are:
1.
Strengthen APHIS Plant Protection and Quarantine’s (PPQ) pest exclusion system;
2.
Optimize domestic pest management and eradication programs; and
3.
Increase the safety of agricultural trade to expand economic opportunities in
the global marketplace.
The 2019 Strategic
Plan goals:
1. Deliver
efficient, effective, and responsive programs.
2. Safeguard
American agriculture.
3. Facilitate safe
U.S. agricultural exports.
I excluded from my
analysis generalized goals and objectives pertaining to employee training,
empowerment, etc.
Each of the plans’
goals is supported by several objectives, and in the 2019 Plan by tactics.
These are the specific actions that are to be taken – and progress measured.
All the objectives and actions in the 2015 Strategic Plan are relevant to APHIS’
Plant Protection and Quarantine program, whereas only a few of the 2019 Plan
are.
Will this mean that
we will lose track of what is happening in important areas?
For now, I provide
a summary of events and progress as reported in the annual reports from 2015 to
2018.
2015 Strategic
Plan Goal 1. Strengthen PPQ’s pest exclusion system. The objectives
called for addressing pest risks at the first opportunity – preferably at the
point of origine; and making better use of the information the agency collects to
target and reduce pest threats.
Strategic Plan Goal 2. Optimizing pest management and eradication. The objectives called for closer coordination with partners to focus combined resources on obtaining the greatest results.
Strategic Plan
Goal 3: Increase the safety of agricultural trade to expand economic
opportunities in the global marketplace. These objectives integrated APHIS into
collaborating with foreign counterparts to promote the development and use of
internationally and regionally harmonized, science-based phytosanitary
measures. The purpose is to reduce barriers to trade, especially U.S.
agricultural exports.
APHIS
also promised to use the best available science, data, and technologies to
strengthen the agency’s effectiveness and deliver results for the industries it
serves.
Assessing
Progress
Unfortunately,
APHIS did not stick to standardized metrics in the annual reports. This lapse undermines
efforts to use the reports to evaluate progress. Use of different metrics are
apparent in reporting on a) numbers of pre-clearance programs, b) Asian gypsy
moth detections; c) volumes of seed imported; d) amounts of illegal imports
seized.
Progress
on Goal 1, Objective 1: Address Risks Early
The
first opportunity to counter a pest risk is offshore – before the product or
crate or container even starts its journey to the U.S.
APHIS
has expanded its off-shore pre-clearance programs under which shipments of
fruit, vegetables, bulbs and plants are inspected overseas – so as to catch
pests before the products even begin their journey. Between 2015 and 2018, the
number of programs grew from 30 programs in an unspecified number of countries to
programs covering 72 different types of commodities in 22 countries.
APHIS
is concerned about the pest risks associated with the huge volume of ornamental
plant cuttings shipped to the US. As pointed out in the 2017 report, more than
half of the bedding plants sold at retail started from a cutting produced in a
greenhouse located offshore – usually in a tropical or subtropical country. The
high-volume imports impose a heavy burden on inspectors at APHIS’ 16 Plant
Inspection Stations. APHIS already had a small program encouraging producers to
follow “clean” procedures in growing plants; in 2016 it involved 17 facilities.
That same year, APHIS began framing a larger program that would provide
incentives to encourage production facilities voluntarily to adopt integrated pest
management measures. However, a
six-month test in 2017
did not demonstrate that the program brought about a statistically significant
reduction in risk. So PPQ and its partners in the U.S. nursery industry agreed
to repeat the pilot during the 2018–2019 shipping season and refine the voluntary
certification program (2018
report).
Post-Entry
Safeguards
A second line of defense is quarantine within the United States after plants are imported – so-called “post-entry quarantine”. This program allows importers to bring in small numbers of plants that pose a particularly high risk of transporting pests so that they can be incorporated into U.S. agricultural (including horticultural) production. These plants are placed in a certified quarantine facility for close observation – usually for a two-year period. Program requirements are described here. Over the years covered by these annual reports, the number of plants released from PEQ varied considerably – as high as 898 in 2017, half as many (425) in 2018, with intermediate numbers in the earlier years. The number of species has varied less – between 10 and 14, with the highest in 2017. I was unable to detect a pattern.
Results of these
efforts – Numbers of pests detected
1. Detections at the Ports
CBP inspectors examining wood packaging material
The 2015 report stated that the agency had detected more new pest detections and saw higher numbers of pest outbreaks than in previous years (but it did not provide specific numbers). Subsequent reports show declines in pests detected (although we cannot evaluate the “pest approach rate” because key information is not collected) [see Appendix II of Fading Forests III, available here] In 2016, APHIS identified 162,000 pests in imported shipments; of this total, 73,700 were quarantine pests. The 2017 report said APHIS identified 143,411 pests in imported shipments; of this total, 71,158 were quarantine pests. In 2018, APHIS identified 140,822 pests; nearly half of this total were quarantine pests.
A particularly dangerous pest: Asian Gypsy Moth
Among the detections reported are those of the Asian gypsy moth egg masses on ships from Asia.
Phytosanitary officials and conservationists have been concerned about this threat since the early 1990s. APHIS and its Canadian counterpart (Canadian Food Inspection Agency) and the two countries’ customs agencies have worked together since then to minimize the likelihood that AGM egg masses will be transported on ships or hard cargo (containers, automobiles, etc.). The most important step was the adoption by the North American Plant Protection Organization link of Regional Standard of Phytosanitary Measures (RSPM) No. 33 in 2009; it was revised in 2015 and 2017.
While
the standard has apparently resulted in significant declines in arrivals of
ships contaminated by egg masses, the lack of
consistent reporting measures make it difficult to compare detection results
from year to year. In the various reports, APHIS reports varying types
of data – e.g., sometimes percentage
of ships, sometimes number of ships, sometimes percentage decline in number of
egg masses found on ships For example, the 2017 report stated that the number
of incoming ships with AGM egg masses had been reduced from 48 in 2014 to 0
2017. The 2018 report is confusing. In a single paragraph (p. 5) it states both
that more than 98% of inspected vessels entering U.S. ports from Asia were free
of AGM; and that the compliance rate hit an all-time high of 92%, a 10% increase
over the previous year’s rate.
The annual reports also
describe regional and international efforts to reduce the likelihood that AGM
egg masses will be transported to North America. The 2016
and 2017 reports described meetings with Canada and Chile – other
countries worried about AGM introductions – and with four “source” countries —
China, Japan, Russia, and South Korea – to promote better compliance with vessel
certification program requirements. Also, APHIS began monitoring for AGM on
U.S. military bases in Japan and South Korea.
The reports also
note progress in ensuring eradication of AGM outbreaks in various U.S.
locations. There had been single AGM moths detected in Oklahoma in 2013 and 2014;
in South Carolina in 2014 and 2015; and in Georgia in 2015. (News releases had
also reported AGM egg masses on a ship in Baltimore harbor in 2013.) The 2017
report notes that after three years of negative surveys, PPQ confirmed that Oklahoma
is free of the pest. The 2018 report said South Carolina and Georgia also had
been declared free of AGM. Surveys continue in treated areas of Washington and
Oregon, where 14 moths were found in 2015 (2017 report).
2. Pests Detected in Sea Containers
a shipping container being offloaded at Port of Long Beach, California
In
2016, PPQ initiated a collaborative exploration with Canada and the shipping and
sea container industries to address pest risks associated with the movement of
sea containers. The goal of the initiative is to develop container-cleaning
guidelines that can be implemented on a global scale. In 2017, PPQ gave a
presentation to the members of the International Plant Protection Convention (IPPC)
re: the complexity of this issue. The IPPC formed a Sea Container Task Force,
which continues to work.
A
specific case (which should not have been a surprise)
In
2017, APHIS was startled to learn from an importer that containers of airplane
parts shipped from Italy were infested by snails. APHIS began working with both
the importers and the suppliers to minimize the presence of snails. I confess
to a sense of irony. Wood packaging from Italy has been a well-recognized
pathway for the movement of snails since at least 1985! How could APHIS staff
be surprised when snails turn up on containers? I hope APHIS’ effort to
persuade Italian machinery manufacturers to clean up their loading docks and
storage facilities are more successful than similar efforts in the past
targetting marble quarries and tile manufacturers.
3. Pests
Detected in Imports of Living Plants and Seeds.
Plant import volumes have averaged about 1.5 billion
units (cuttings, whole plants, other propagative materials) per year in 2015
through 2018. (The recent import level is less than half the volume of imported
plants before the Great Recession in 2008 – those imports exceeded 3.15 billion
plants in 2007 – Liebhold et al.
2012; full citation at end of blog.) Reported imports of seed were sometimes in
pounds, sometimes in tons (not clear whether Imperial or metric tons), and once
in kilograms. So, if my math is correct, seed imports probably varied from a
low of 1.39 million pounds in 2018 to a high of 3.74 million pounds in 2017.
The number of shipments in which the plant units were packaged varied from a
high of more than 19,000 in 2015 to a low of 17,000 in 2017. Again, I cannot
detect a pattern.
The number of quarantine pests detected varied from
a low of 690 in 2016 to a high of 1,173 in 2918. That last year also had the
highest number of plant units imported – 1.7 billion – 100,000 to 200,000 more
than in previous years. Whether these detection numbers accurately reflect the
true pest approach rate via this
pathway is difficult to know. A study by Liebhold et al. (2012 full citation at end of blog) found that up to 72% of
infested shipments were not detected by inspectors.
Progress
on Goal 1, Objective 2: Making Better Use of Information
A
major thread in past analyses of APHIS programs is the poor use of data to
evaluate and improve program efficacy. APHIS is trying to overcome these
deficiencies (although note the use of inconsistent numbers in the annual
reports).
One
important focus is the on-going effort to implement risk-based sampling
protocols at the Plant Inspection Stations. APHIS says its goal is to ensure
that an inspector
operating with 80% efficiency is able to detect any shipment with a 5%
infestation level. The level of confidence that such a detection has been
accurate should be 95%. Developing the sampling and inspection system has been
a challenge; APHIS adjusted one aspect of it in 2018 (according to that year’s
annual report). APHIS is also using statistical methods to try to estimate the
pest approach rates for specific types of plant material (2017 report).
APHIS is also striving to integrate its data analysis programs with those of DHS Bureau of Customs and Border Protection (CBP). A pilot program testing risk-based sampling at four Texas border ports focuses on imported commodities rather than the accompanying wood packaging. This is unfortunate given the high levels of detection of wood packaging from Mexico that is in violation of applicable international rules in ISPM#15). [See my discussion from February 2017.]
Finally,
APHIS is testing use of molecular diagnostics to detect diseases that may not
be found through visual inspection –
although this is still experimental in 2018 after more than two years of
evaluation.
Progress
on Goal 2: Optimizing Pest Management and Eradication
Remember that the
objectives emphasized coordinating with and “wisely us[ing]” partners’
abilities.
Seizures of
illegal imports
Again, the reporting units vary so it is hard to compare between years. In 2015 and 2016, seizures were reported in pounds of prohibited plants, plant products, meat, and meat products that had entered the country illegally. Such seizures fell from more than 290,000 pounds in 2015 to 102,000 pounds in 2016. In 2017 and 2018, seizures were reported as numbers of prohibited items and their retail value. In 2017, APHIS seized 2,347 prohibited agricultural items valued at more than $554,000 from retail stores, internet sales, and express shipment courier inspections. In 2018, seizures rose to 3,222 prohibited items valued at over $2.6 million.
011817.N.DNT.INFESTEDFURNITUREc2 — The burrowing larvae of a velvet longhorned beetle was found in rustic log furniture imported form China. State insect experts are asking people who may have purchased imported log furniture to check for inspect damage and report any findings of insects. Photo courtesy Minnesota Department of Agriculture
APHIS also
sometimes recalled items – there were 24 national recalls in 2017, 28 in 2018.
In 2016, PPQ’s Furniture Recall Team coordinated a nationwide consumer-level
recall of imported pine furniture after customers complained that insects,
later identified as brown fir longhorned beetles, were emerging from the
furniture. The combined federal-state-retailer effort recovered and destroyed
83% of the purchased furniture pieces and 100 % of the furniture that remained
in the warehouse. This effort won APHIS’ internal Safeguarding Award in 2016.
Pest
Eradications
(I include here only tree pests; the reports note success on European grape
vine moth and pink bollworm.)
Annual reports noted gradual progress in eradicating Asian longhorned beetle outbreaks. As of 2016, APHIS reported eradication of 85% of the ALB-infested area in New York, 34% of the area Massachusetts, and 15% of the OH infestation. In 2018, APHIS announced eradication of ALB from two townships in Clermont County, Ohio.
In 2016 APHIS reported that it has begun focusing the emerald ash borer program on biocontrol. The agency reported releasing more than 1.2 million parasitic wasps in 20 states in what the agency called “trial releases” in 2015. By 2017 the agency released wasps in 25 states and the District of Columbia and reported detections of reproducing wasp populations in 14 states. In 2018, APHIS released more than 1 million wasps – again in 25 states; and reported recoveries of offspring in 17 states. In that last year, APHIS issued a formal proposal to end the regulatory program restricting movement of EAB vectors. In earlier blogs I explained my opposition to this proposal. See earlier blogs here and here.
This
proposal was adopted after APHIS implemented a new “decision framework” (see
2016 report). Presumably APHIS considers this framework to implement Goal 2,” Optimize
domestic pest management and eradication programs.” Given the
controversy around the emerald ash borer proposal, however, I am skeptical that
it fulfills the two objectives – coordinating with partners and using partners’
“ unique capacities … to strengthen and extend PPQ’s domestic programs.” Instead,
to me, this decision reflects the agency’s eagerness to dump difficult programs
onto others – in this case, state agencies and conservation organizations. For
more on this “dumping” proclivity, see also “FRSMP” below.
In 2018 APHIS also reported expanding its engagement with the spotted lanternfly — which I think should have been much more vigorous earlier [see here]. APHIS said it would focus on the leading edge of the infestation in Pennsylvania, while the Pennsylvania Department of Agriculture took the lead within the core infested area. APHIS also said it would assist State departments of Agriculture in Virginia, New Jersey, and Delaware, where outbreaks have been detected.
Surveys
Pest surveys are one tool for early detection of pests, so they are important to pest eradication and management. Surveys have long been collaborative efforts with the states and others, funded through the CAPS and Farm Bill programs (see below). The number of pests targeted in the surveys have crept up from 346 in 2015 to 386 in 2018. The number of quarantine pests detected varies year-to-year: 16 in 2016; 30 in 2017; 12 in 2018. According to the report, all were detected before they could cause significant damage.
APHIS has been
testing use of both dogs and unmanned aircraft (drones) for surveys of tree
pests. Dogs have shown promise in detecting AGM egg masses on ships, coconut
rhinoceros beetle in mulch piles, and insect frass in wood packaging.
Other Initiatives
APHIS
is actively pressing for widespread adoption of electronic phytosanitary
certificates, which it expects to both ease processing burdens and reduce
opportunities for fraud. Efforts include test exchanges of electronic
certificates with a growing number of countries and development of an action
plan to be presented to the International Plant Protection Convention
decision-making body in 2018.
Another
initiative is to develop a holistic, integrated management systems approach to
reduce risks associated with international movement of seed (a very complex trade!).
Farm
Bill projects
Funding
for projects under
the Plant Pest and Disease Management and Disaster
Program (Section
10007 of the Farm Bill; now Section 7721 of the Plant Protection Act) was not
reported in the 2015 or 2016 annual reports. My analysis of the program website
found that $62.5 million worth of projects was funded in FY15; 58.25 million was
funded in FY17. By 2018, a total of $75 million worth of projects was funded.
The number of
projects funded has increased as a result – from about 430 in 2015 and 2016 to
483 in 2017 and 519 in 2018. According
to my calculations, the proportion of the funding going to tree pests has
averaged a little over 10% in most years. 2016 saw a spike because of spending
to suppress the spotted lanternfly in Pennsylvania and to eradicate AGM
outbreaks in Washington and Oregon.
Federally
Recognized State Managed Phytosanitary (FRSMP) Program
In
theory, the FRSMP program supports states’ efforts to prevent pests that are no
longer federally regulated from entering the state’s territory. To be covered
under the FRSMP Program, a pest must pose an economic or environmental risk to
a state, and the state must have a program in place to eradicate, exclude or
contain it. In those cases, a State may petition PPQ to list the species under
the program. Between 2010 and 2018, APHIS, in collaboration with the National
Plant Board, changed the regulatory status of 105 pests. I worry that at least
some of these pests should continue to be the target of a federal program. My
worry is exacerbated by APHIS’ plan to deregulate the emerald ash borer
(described above).
Goal 3: International
Coordination to Develop Science-Based Standards
The
APHIS annual reports demonstrate APHIS’ active engagement with international
standard-setting bodies in pursuit of its goal of pre-empting conflicts with
trade partners by getting international agreement to appropriate phytosanitary
measures. Since 2016, the International Plant Protection Convention has adopted
36 new international standards. The North American Plant Protection
Organization adopted a new standard for using systems approaches to manage pest
risks associated with the movement of forest products. APHIS assigns staff to participate
on expert panels and committees, comments on draft standards, and help define
the organizations’ agendas.
Forest-pest
related issues addressed through one or both of these organizations include
both an international and regional standard for the movement of wood products,
and adoption of two new treatments for wood packaging. APHIS was also a key
player in organizing two workshops aimed at improving compliance with the
international wood packaging standard (ISPM#15) and another aimed at improving compliance
with the ship-sanitation program intended to curtail transport of AGM egg
masses. APHIS also coordinates closely with Australia, New Zealand, as well as Canada
(called “the Quads”), to advance shared standard-setting priorities at the IPPC
and launch key initiatives of mutual interest.
As I said at the beginning of the blog, APHIS issued a new Strategic Plan [available here] in autumn 2018. A table in Appendix A of the report provides support for some of my concerns.
Regarding
APHIS’ backing away from regulatory programs and difficult pests, the table shows
that 11 deregulatory actions were published in FY2017; the target for FY18 is 10,
the target for FY19 is 15. Furthermore, Objective 1.3, states that APHIS will
remove obstacles by ending regulations that place burdens on stakeholders but that
are not supported by current science or practices. APHIS has also reinstated an
internal executive regulatory management group to identify APHIS’ regulatory
needs early and track them through approval.
I
am even more concerned that the “performance measure” in the table in Appendix
A anticipates that the percentage of high-risk pests surveyed for under the
CAPS program will fall from 96% in FY17 to just 80% in FY19.
The
2019 Strategic Plan continues an earlier emphasis on science-based decisions,
modernizing procedures, improving utilization of data, the need to be flexible
and adjust to new situations, to work closely with partners, and to maintain
leadership role in international bodies aimed at achieving protection goals
while promoting safe trade. The vast majority of examples and specific actions listed
in the plan pertain to animal disease issues; some actions could be interpreted
as applying to both animal and plant sanitary issues. The table in Appendix A
anticipates that ten new regional or international standards will be adopted in
both FY2018 and FY2019.
The few plant-specific actions in
the plan include the following matters that continue from previous years – but
without any recognition of problems revealed in the annual reports:
•
Imported plant cuttings that are produced in approved offshore facilities will
be processed through a streamlined system. No mention is made that the 2017 pilot
program failed to demonstrate the expected reduction of pest risk.
•
By FY2019 (the current year), 60% of incoming shipments of plants will be inspected
under the Risk Based Sampling (RBS) system. No mention is made of the still “in
development” aspect of this system, as revealed in the 2018 and other annual
reports.
•
Development will continue of a new regulatory approach for seed imports based
on Regulatory Framework for Seed Health (ReFreSH) (a systems approach which has
been under development for several years).
•
Addressing the threat of invasive pests and diseases associated with the
international movement of sea containers (an international initiative begun a
few years ago).
•
Strengthening the North American perimeter against pest threats from outside
the region.
•
Preventing the sale of prohibited plant material via the internet or
e-commerce.
SOURCE
Liebhold,
A.M., E.G. Brockerhoff, L.J. Garrett, J.L. Parke, and K.O. Britton. 2012.
Live plant imports: the major
pathway for forest insect and pathogen invasions of the US. Frontiers
in Ecology and the Environment, 10(3): 135-143. Online at: http://www.ncrs.fs.fed.us/pubs/jrnl/2012/nrs_2012_liebhold_001.pdf. Accessed December 7, 2012.
Posted
by Faith Campbell
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welcome comments that supplement or correct factual information, suggest new
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frogs in California killed by chytrid fungus photo by Rick Kyper, US Fish and Wildlife Service
I expect you have heard about the report issued on May 6 by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services. The executive summary is available here
Based on thousands of scientific
studies, the report concludes that the biosphere, upon which humanity as a whole
depends, is being altered to an unparalleled degree across all spatial scales. The
trends of decline are accelerating. As many as 1 million species (75% of which are
insects) are threatened with extinction, many within decades.
Humans dominate Earth: natural
ecosystems have declined by 47% on average. Especially hard-hit are inland
waters and freshwater ecosystems: only 13% of the wetland present in 1700
remained by 2000. Losses have continued rapidly since then.
The report lists the most important
direct drivers of biodiversity decline – in descending order – as habitat loss
due to changes in land and sea use; direct exploitation of organisms; climate
change; pollution; and invasive species. The relative importance of each driver
varies across regions.
If you have been paying attention, these
conclusions are not “news”.
However, the report serves two valuable
purposes. First, it provides a global overview, a compilation of all the data
and trends. Second, the report ties the direct drivers to underlying causes
which are in turn underpinned by societal values and behaviors. Specifically
mentioned are production and consumption patterns, human population dynamics
and trends, trade, technological innovations, and governance (decision making
at all levels, from local to global).
The report goes to great lengths to
demonstrate that biological diversity and associated ecosystem services are
vital for human existence and good quality of life – especially for supporting
humanity’s ability to choose alternative approaches in the face of an uncertain
future. The report concludes that while more food, energy and materials than
ever before are now being supplied to people, future supplies are undermined by
the impact of this production and consumption on Nature’s ability to provide.
The report also emphasizes that both the
benefits and burdens associated with the use of biodiversity and ecosystem
services are distributed and experienced inequitably among social groups,
countries and regions. Furthermore, benefits provided to some people often come
at the expense of other people, particularly the most vulnerable. However, there are also synergies – e.g., sustainable agricultural practices
enhance soil quality, thereby improving productivity and other ecosystem
functions and services such as carbon sequestration and water quality
regulation.
The report contains vast amounts of data
on the recent explosion of human numbers and – especially – consumption – of
agricultural production, fish harvests, forest products, bioenergy production …
and on the associated declines in “regulating” and “non-material contributions”
ecosystem services. In consequence, the report concludes, these recent gains in
material contributions are often not sustainable.
While invasive species rank fifth as a
causal agent of biodiversity decline globally, alien species have increased by
40% since 1980, associated with increased trade and human population dynamics
and trends. The authors report that nearly 20% of Earth’s surface is at risk of
bioinvasion. The rate of invasive species introduction seems higher than ever
and shows no signs of slowing.
The report notes that the extinction
threat is especially severe in areas of high endemism. Invasive species play a
more important role as an extinction agent in many such areas, especially
islands. However, some bioinvaders also have devastating effects on mainlands;
the report cites the threat of the pathogen Batrachochytrium
dendrobatidis to nearly 400 amphibian species worldwide.
The report also mentions that the combination
of species extinctions and transport of species to new ecosystems is resulting
in biological communities – both managed and unmanaged — becoming more similar
to each other — biotic homogenization.
The report notes that human-induced
changes are creating conditions for fast biological evolution of species in all
taxonomic groups. The authors recommend adopting conservation strategies
designed to influence evolutionary trajectories so as to protect vulnerable species
and reduce the impact of unwanted species (e.g.,
weeds, pests or pathogens).
The report says conservation efforts
have yielded positive outcomes – but they have not been sufficient to stem the
direct and indirect drivers of environmental deterioration. Since 1970, nations
have adopted six treaties aimed at protection of nature and the environmental,
but few of the strategic objectives and goals adopted by the treaties’ parties
are being realized. One objective that is on track to partial achievement is
the Aichi Biological Diversity Target that calls for identification and
prioritization of invasive species.
That might well be true – but I would not consider global efforts to manage invasive species to be a success story in any way. I have blogged often about studies showing that introductions continue unabated … and management of established bioinvaders only rarely results in measurable improvements. [For example, see here and here.]
The report gives considerable attention
to problems caused by some people’s simultaneous lack of access to material
goods and bearing heavier burden from pollution and other negative results of
biodiversity collapse. Extraction of living biomass (e.g. crops, fisheries) to meet the global demand is highest in
developing countries whereas material consumption per capita is highest in developed countries. The report says that
conservation of biodiversity must be closely linked to sustainable approaches
to more equal economic development. The authors say both conservation and economic
goals can be achieved – but this will require transformative changes across
economic, social, political and technological factors.
One key transformation is changing
people’s conception of a good life to downplay consumption and waste. Other
attitudinal changes include emphasizing social norms promoting sustainability
and personal responsibility for the environmental impacts of one’s consumption.
Economic measures and goals need to address inequalities and integrate impacts
currently considered to be “economic externalities”. The report also calls for inclusive
forms of decision-making and promoting education about the importance of
biodiversity and ecosystem services.
Economic instruments that promote
damaging, unsustainable exploitation of biological resources (or their damage
by pollution) include subsidies, financial transfers, subsidized credit, tax
abatements, and commodity and industrial goods prices that hide environmental
and social costs. These need to be changed.
Finally, limiting global warming to well
below 2oC would have multiple co-benefits for protecting
biodiversity and ecosystem services. Care must be exercised to ensure that large-scale
land-based climate mitigation measures, e.g.,
allocating conservation lands to bioenergy crops, planting of monocultures,
hydroelectric dams) do not themselves cause serious damage to biodiversity or
other ecosystem services.
The threats to biodiversity and
ecosystem services are most urgent in South America, Africa and parts of Asia. North
America and Europe are expected to have low conversion to crops and continued
reforestation.
Table SPM.1 lays out a long set of approaches
to achieve sustainability and possible actions and pathways for achieving them.
The list is not exhaustive, but rather illustrative, using examples from the
report.
Posted by Faith Campbell
We
welcome comments that supplement or correct factual information, suggest new
approaches, or promote thoughtful consideration. We post comments that disagree
with us — but not those we judge to be not civil or inflammatory.
spotted lanternfly; photo by Holly Raguza, Penn. Dept. of Agriculture
I last blogged about the spotted lanternfly (Lycorma delicatula) two years ago. At that time, this insect from Asia (where else?) was established in some portions of six counties in southeastern Pennsylvania. While its principal host is tree of heaven (Ailanthus altissima), it was thought to feed on a wide range of plants, especially during the early stages of its development. Apparent hosts included many of the U.S.’s major canopy and undertory forest trees, e.g., maples, birches, hickories, dogwoods, beech, ash, walnuts, tulip tree, tupelo, sycamore, poplar, oaks, willows, sassafras, basswood, and elms. The principal focus of concern, however, is the economic damage the lanternflies cause to grapes, apples and stone fruits (e.g., peaches, plums, cherries), hops, and other crops.
In
the two years since my first blog, the spotted lanternfly has spread – both
through apparent natural flight (assisted by wind) and through human transport
of the egg masses and possibly adults. By autumn 2018, detections of one or a
few adults – alive or dead – had been found in six additional states:
Connecticut, Delaware, Maryland, New Jersey, New York, and Virginia.
spotted lanternfly quarantines (blue) & detection locations (yellow) prepared by Cornell University
How
many of these detections signal an outbreak?
It is too early to know.
Impacts of the
Government Shutdown
Unfortunately
the federal government shutdown forced the cancellation of the annual USDA
invasive species research meeting that occurs each January. The spotted
lanternfly was to be the focus of six presentations. The most important of
these was probably APHIS’ explanation of “where we are and where we are going.”
The cancellation eliminated one of the most important opportunities for
researchers to exchange information and ideas that could spur important
insights. Equally important, the cancellation hampered communication of
insights to practitioners trying to improve the pest’s management.
One
pressing question was not on the meeting’s agenda, however. Would a much more
aggressive and widespread response in 2014, when the lanternfly was first
detected, have eradicated this initial
outbreak? I have long thought that this
question should be asked for every new pest program, so that we learn whether a
too-cautious approach has doomed us to failure. However, authorities never
address the issue – at least not in a public forum.
The shutdown also had an even more alarming impact. It interruptedaid by USDA APHIS and the Forest Service to states that should be actively trying to answer this question. Winter is the appropriate season to search for egg masses. It is also the season to plan for eradication projects.
spotted lanternfly egg mass; New York Department of Environmental Conservation
For the first several years, funding of studies of the lanternfly’s lifecycles and host preferences, research on possible biological or chemical treatments, and outreach and education came in the form of competitive grants under the auspices of the Farm Bill Section 10007. This funding totaled $5.5 million to Pennsylvania.
This commitment pales compared to Asian longhorned beetle or emerald ash borerh— which were also poorly known when they were first detected in the United States.
At the same time, the Pennsylvania infestation spread. It is now known to be established in portions of 13 counties and outbreaks were detected in neighboring Delaware and Virginia. h
This spread – and resulting political pressure – persuaded APHIS to multiply its engagement. A year ago, USDA made available $17.5 million in emergency funds from the Commodity Credit Corporation (that is, the funds are not subject to annual Congressional appropriation). APHIS said it would use the additional funds to expand its efforts to manage the outer perimeter of the infestation while the Pennsylvania Department of Agriculture would focus on the core infested area. APHIS said it would use existing (appropriated) resources to conduct surveys, and control measures if necessary, in Delaware, Maryland, New Jersey, New York and Virginia.
Pennsylvania: infestation established (quarantine declared) in portions of thirteen counties (Berks, Bucks, Carbon, Chester, Delaware, Lancaster, Lebanon, Lehigh, Monroe, Montgomery, Northampton, Philadelphia, Schuylkill). The quarantine regulates movement of any living stage of the insect brush, debris, bark, or yard waste; remodeling or construction waste; any tree parts including stumps and firewood; nursery stock; grape vines for decorative or propagative purposes; crated materials; and a range of outdoor household articles including lawn tractors, grills, grill and furniture covers, mobile homes, trucks, and tile or stone. See the regulation here: https://www.agriculture.pa.gov/Plants_Land_Water/PlantIndustry/Entomology/spotted_lanternfly/quarantine/Pages/default.aspx
Delaware: The state had been searching for the insect since the Pennsylvania outbreak was announced. After detection of a single adult female in New Castle County in November 2017, survey efforts and outreach to the public were intensified. Another dead adult spotted lanternfly was found in Dover, Delaware, in October 2018.
Virginia: infestation established (quarantine declared) in one county. Multiple live adults and egg cases of spotted lanternfly were confirmed in the town of Winchester, Virginia (Frederick County), in January 2018. As noted in my earlier blog, this region is important for apple and other orchard crops and near Virginia’s increasingly important wine region.
New Jersey: The New Jersey Department of Agriculture began surveying for lanternflies along the New Jersey-Pennsylvania border (the Delaware River) once the infestation was known. It found no lanternflies before 2018. In the summer, however, live nymphs were detected in two counties, Warren and Mercer. In response, the state quarantined both those counties and one located between them, Hunterdon. The state planned to continue surveillance in the immediate areas where the species has been found as well as along the Delaware River border in New Jersey.
New York: In 2017, a dead adult lanternfly was found in Delaware County.
State authorities expressed concern about possible transport of lanternflies from the Pennsylvania infested area.
In Autumn 2018, New York authorities confirmed several detections, including a single adult in Albany and a second single adult in Yates County. In response, the departments of Environmental Conservation and Agriculture and Marketing began extensive surveys throughout the area. Initially they found no additional lanternflies.
However, a live adult was later detected in Suffolk County (on Long Island).
Connecticut: a single dead adult was found lying on a driveway at a private residence in Farmington, CT, in October 2018. The homeowner was a state government employee educated about the insect. Relatives had recently visited from Pennsylvania (Victoria Smith, Connecticut Agricultural Experiment Station, pers. comm.). Searches found no other spotted lanternflies on the property. The state plans additional surveys in the area to confirm that no other spotted lanternflies are present.
Maryland: A single adult spotted lanternfly (male) was caught in a survey trap in the northeast corner of Cecil County near the border of Pennsylvania and Delaware (an area of known infestation) in October 2018. Because of the lateness of the season and sex of the insect, the Maryland Department of Agriculture does not believe that the lanternfly has established there.
All
the affected states are encouraging citizens to report any suspicious finds.
Posted
by Faith Campbell
We
welcome comments that supplement or correct factual information, suggest new
approaches, or promote thoughtful consideration. We post comments that disagree
with us — but not those we judge to be not civil or inflammatory.
Prompted
by the rising number of Phytophthora-caused
diseases in forests on several continents, in 1999 the International Union of
Forest Research Organizations (IUFRO) formed the IUFRO Working Party 7.02.09
‘Phytophthora Diseases of Forest Trees’. Last spring This group published a
global overview of Phytophthora
diseases of trees (Jung et al. 2018; see
full citation at the end of this blog).
The
study covers 13 different outbreaks of Phytophthora-caused
disease in forests and natural ecosystems of Europe, Australia and the
Americas.
The
picture is alarming!
Jung et al. state definitively that the
international movement of infested nursery stock and planting of reforestation
stock from infested nurseries have been the main pathway of introduction and
establishment of Phytophthora species
in these forests.
The Picture: A
Growing List of Diseases, Species, and Places Affected,
Jung et al. note that, during the past six decades, the number of previously unknown Phytophthora declines and diebacks of natural and semi-natural forests and woodlands has increased exponentially. The vast majority of these disease complexes have been driven by introduced invasive Phytophthora species. In 1996, 50 Phytophthora species were known. In the 20 years since then, more than 100 new Phytophthora species have been described or informally designated. One study (Tsao 1990) estimated that more than 66 % of all fine root diseases and more than 90 % of all collar rots of woody plants are caused by Phytophthora spp. Many of these had previously been attributed to abiotic factors or secondary pathogens. One example – surprising to me, at least – is that decline of mature beech trees in Central Europe is linked to Phytophthora rather than beech bark disease!
Several
of the disease complexes described in Jung et
al. 2018 are causing heartrending destruction of unique floras, e.g., jarrah, tuart, and other
communities of western Australia and kauri forests of New Zealand. The authors expect
increasing damage to the Mediterranean maquis
in the future. They list these among other examples:
Ink disease of chestnuts worldwide
Oak declines and diebacks in Europe and North America
Decline and mortality of alders (Alnus species) in Europe
Decline and mortality of Port-Orford cedar (Chamaecyparis lawsoniana) in Europe and North America
Kauri dieback in New Zealand link to earlier blog
Decline and mortality of Austrocedrus chilensis and Juniperus communis in Argentina and Europe
Diebacks of natural ecosystems in Australia
Decline and dieback of the Mediterranean maquis vegetation
Decline and dieback of European beech in Europe and the US
Dieback and mortality of southern beech (Nothofagus species) in the United Kingdom and Chile
‘Sudden Oak Death’ and ‘Sudden Larch Death’ in the US and United Kingdom
Leaf and twig blight of holly (Ilex aquifolium) in Europe and North America
Needle cast and defoliation of Pinus radiata in Chile
Several
of the Phytophthoras are causing
severe damage on several continents:
P. cinnamomi in Europe,
North America, and Australia
P. austrocedri in South America,
Europe, and western Asia
P. ramorum in Europe and
North America
P. lateralis in North America
and Europe.
Often,
the genetic makeup of the Phytophtoras
species varies in these different locations. These differences indicate separate
introductions and the existence of sexual reproduction and continuing evolution
in response to conditions.
WhyPhytophthoras
are Spreading via the Plant Trade and Nursery Practices
First,
Phytophthora species are able to
survive unsuitable environmental conditions over several years as dormant
resting structures in the soil or in infected plant tissues. When environmental
conditions become suitable, the resting spores germinate – often prolifically. Since
visible symptoms might not appear for considerable time after infection because
the mechanism is progressive destruction of the fine root system, detection of
the disease is delayed, further undermining control.
Second,
most of the Phytophthora species causing
disease complexes were unnoticed as
co-evolved species in their native environment. Often they were unknown to
science before their introduction to other continents – where they become
invasive on naïve plant species. Consequently, these species are not captured
by the international plant health system, which is based on lists of recognized
“pest” species.
Third,
the common nursery practice of applying fungicides or fungistatic chemicals masks
the presence of pathogens – another way plants pass unnoticed through phytosanitary
controls. These chemicals do not, however, kill the pathogen.
Fourth,
the importation into receiving nurseries of plants from around the world
provides ample opportunity for the introduced Phytophthoras to hybridize. The interspecific hybrids may differ in
host range and virulence from the parent species, thus making predictions about
the potential effects of an ongoing invasion even more difficult.
Fifth,
the nurseries or plantings in gardens or restoration projects also provide suitable
environments for prolific germination and spread.
All
of these risks were first enumerated by the eminent British pathologist Clive
Brasier a decade ago! (See Brasier et al.
2008 citation at the end of the blog.)
As Jung et al. 2018 point out, the scientific community has repeatedly urged regulators to require the use of preventative system approaches for producing Phytophthora-free nursery stock (see references in the article). Scientists have provided research-based guidance to reduce the risk of infestation. Such measures are being implemented by only some nurseries in the US. For example, USDA APHIS has specific requirements for nurseries that ship hosts of P. ramorum in interstate commerce after the nurseries or the plants have tested positive. More broadly, APHIS, the states, and the nursery industry are in the second round of pilot testing of an integrated measures approach to managing all pests under the Systems Approach to Nursery Certification (SANC) program
At the international level, the International Plant Protection Convention has adopted ISPM#36, which also envisions greater reliance on systems approaches. However, the preponderance of international efforts to protect plant health continue to rely on visual inspections that look for species on a list of those known to be harmful. Yet we know that most damaging Phytophthoras were unknown before their introduction to naïve ecosystems.
Furthermore,
use of fungicides and fungistatic chemicals is still allowed before shipment.
As pointed out by several experts beginning with Dr. Brasier but including Liebhold et al. 2012, Santini et al. 2013, Jung et al. 2016, Eschen et al. 2017, this approach has failed to halt spread of highly damaging pathogens. (I note that the list of such pathogens is not limited to Phytophthoras; see the description of ohia rust in Hawai`i, Australia, and New Zealand).
Jung et al. 2018 also call for increasing the genetic resistance of susceptible tree species. The authors regard this as the most promising sustainable management approach for stabilizing declining natural ecosystems and for reintroducing susceptible tree species at sites with high disease impact. See my blogs about efforts to enhance U.S. tree-breeding posted earlier this year.
SOURCES
Brasier
CM. 2008. The biosecurity threat to the UK and global environment from
international trade in plants. Plant Pathology 57: 792–808.
Jung
T, Orlikowski L, Henricot B, et al.
2016. Widespread Phytophthora infestations in European nurseries put forest,
semi-natural and horticultural ecosystems at high risk of Phytophthora
diseases. Forest Pathology 46: 134–163.
Jung,
T., A. Pérez-Sierra, A. Durán, M. Horta Jung, Y. Balci, B. Scanu. 2018. Canker
and decline diseases caused by soil- and airborne Phytophthora species in forests
and woodlands. Persoonia 40, 2018: 182–220
Open Access!
Liebhold
AM, Brockerhoff EG, Garrett LJ, et
al. 2012. Live plant imports: the major pathway for forest insect and
pathogen invasions of the US. Frontiers in Ecology and Environment 10: 135–143.
Santini
A, Ghelardini L, De Pace C, et al.
2013. Biogeographic patterns and determinants of invasion by alien forest
pathogens in Europe. New Phytologist 197: 238–250.
Tsao
PH. 1990. Why many Phytophthora root rots and crown rots of tree and
horticultural crops remain undetected. Bulletin OEPP/EPPO Bulletin 20: 11–17
Posted
by Faith Campbell
We
welcome comments that supplement or correct factual information, suggest new
approaches, or promote thoughtful consideration. We post comments that disagree
with us — but not those we judge to be not civil or inflammatory.
