The native hardwood trees of southern California are under threat from several non-native insects and insect/pathogen complexes. I provided some recent information on one of these, the Kuroshio shot hole borer, in April; and a description of Californians’ efforts to counter the threat in August of last year. I think it is time to provide a more comprehensive update on the species.
I have blogged several times about the damage being caused to riparian trees in southern California by the polyphagous and Kuroshio shot hole borers – collectively referred to as the “invasive shot hole borers” or ISHB.
One of the most interesting sources of information about the shot hole borers are the series of visual surveys carried out by Orange County Parks under the leadership of Cathy Nowak (who has now retired). The most recent surveys were conducted in spring 2018 while deciduous trees were still dormant, so those estimates are based on the number of beetle gallery holes detected. An estimated 52,000 trees in the County’s parks are infested by either PSHB or KSHB. Eight regional parks and one historic house were surveyed. Only one large park remains uninfested. Comparing the results in 2018 to those of earlier surveys showed that percentages of host trees (in which the beetle can reproduce) that are infested rose over 2 years or less in seven of the parks – from a 9% increase in one park to a five-fold increase at another park with very low numbers of trees and low overall infestation rate earlier. The second highest increase is 89%.
The most heavily hit hosts are species long recognized as hosts See writeup on the borers here. Those with infestation rates exceeding 70% in one or more parks were
Acacia sp
Alnus rhobifolia (white alder)
Baccharis salicifolia (mule fat)
Erythrina caffra (coral tree)
Koelreuteria bipinnata (Chinese Flame tree*)
Koelreuteria paniculata (golden raintree)
Liquidambar styrachiflua (sweetgum)
Parkinsonia aculeate (palo verde)
Platanus occidentalis (American Sycamore)
Platanus racemose (California sycamore)
Platanus x hispanica (London plane)
Populus fremontii (Fremont cottonwood)
Populus trichocarpa (black cottonwood)
Quercus robur (English oak)
Salix spp. (willow)
* Chinese flame trees support ISHB only within cankered wood – other parts of the tree excrete thick gumming sap that protects.
Current information supports the vulnerability of California sycamore, and guidance that those seeking to learn whether the beetles have established should focus their surveys on sycamores.
As I have noted numerous times, several reproductive hosts are widespread in other parts of the country and could presumably support infestations there. These include box elder (not included in the Orange County surveys), sweetgum, and two magnolias – southern magnolia (M. grandiflora) and sweet bay (M. virginiana). Thirty-eight percent of the Magnolia grandiflora in one park were infested, although none was in three other parks. Koelreuteria spp. are a widely planted exotic across the country – although their role in spreading the disease appears to be limited by fact that they support ISHB development only in cankered wood. Birches have not been determined to be reproductive hosts, although one birch tree in one park had insect exit holes. Casuarina cunnninghamiana is also not known to be a reproductive host; trees in this genus are widespread invaders in Florida.
The good news is that none of a total of 12 southern live oaks (Quercus virginiana) growing in three parks had been attacked.
The goldspotted oak borer attacks California black oak, coast live oak, and canyon live oak. It is now widespread and continuing to spread in San Diego County. Officials report that is now established in more than 10 parks in the County.
There is a heavy GSOB infestation in Idyllwild, on the eastern edge of Riverside County. This outbreak is clearly linked to importation of infested firewood. Due to the heavy 2017 fire season, planned removal of “amplifying” trees (heavily infested trees that support large numbers of reproducing beetles) did not occur – and the outbreak is growing. Trees in the San Bernardino National Forest are at risk; 13 were removed in 2017.
In Los Angeles County, so far only one site has been infested – Green Valley (which includes both private land and nearby portions of the Angeles National Forest). An estimated 50,000 oaks are in the area. Officials are removing the “amplifier” trees; they expect they might have to remove close to 3,000 trees at a cost of $6 million. Officials are also treating some trees.
A newly detected heavy infestation has been detected at campgrounds in the Trabuco Ranger District in the Cleveland National Forest. Forest Service officials are debating management options, with an eye to protecting as many coast live oaks as possible. They have had success in the past by treating some trees with chemicals.
Meanwhile, scientists will be trying to evaluate the effect of fire since the 2017 fires burned several infested areas, e.g., Weir Canyon in Orange County.
The principal management strategy is to identify and remove heavily infested “amplifier” trees. The wood and bark must be disposed of properly and quickly – if the wood is left on the ground over night, people take it – thereby spreading the insects. High-value trees that are not heavily infested can be protected by application of the topical contact insecticide Carbaryl on the lower trunk. Officials are also experimenting with oak restoration using either planting of acorns or promoting root sprouting of trees that have had to be cut down.
Thousand Cankers Disease
Thousand cankers disease of walnuts is very widespread throughout California, but it is not causing widespread rapid tree deaths. Juglans californica has multiple stems. If one is killed, the others usually survive. The impact on J. hindsii is greater because it has a single stem and is grown as a street tree. California officials last conducted a survey of walnuts in the state in 2015, at the height of the drought. They appear to be confident that the age of this survey has not affected their assessment of the risk.
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.
As the federal government continues to dawdle in responding to invasive species challenges, some states are ramping up their efforts in significant ways.
California: New Legislation Creates a Program – but Only for One Year
The California state legislature has created a new invasive species program that focuses on those bioinvaders that threaten native ecosystems and the urban environment. It thus addresses some of the criticisms that I have previously levelled at the California Department of Food and Agriculture (CDFA) [see my earlier blogs here and here]
The new program has been established for one year; it will have to be renewed by the legislature next year.
The program results from adoption of legislation that combines what were initially two bills:
Assemblyman Timothy Grayson introduced AB 2470. This bill provided a legal foundation for the California Invasive Species Council and its Invasive Species Advisory Committee. It also provided funding for early detection and control projects targetting high-priority species, including weed management areas; and for supportive research and diagnostics work by the University of California.
Assemblywomen Lorena Gonzalez-Fletcher introduced AB 2054 focused specifically on the invasive shot hole borers [see descriptions of the polyphagous and Kuroshio shot hole borer here https://www.dontmovefirewood.org/ ]. The “Protect California Trees with Shot Hole Borer Beetle Prevention” (1) established a framework for a coordinated statewide effort; (2) instructed the Invasive Species Council of California and the California Invasive Species Advisory Committee to coordinate with state and local agencies and stakeholder groups to develop a plan to suppress the disease spread by this beetle.
The final legislation provided the full $5 million for addressing the shot hole borer but cut funding for the other components of the combined programs to just $2 million (so, a total of $7 million).
State officials have begun developing a shot hole borer management plan; they are expected to get input from a subcommittee by the Invasive Species Advisory Committee. The Advisory Committee held a meeting in mid-July to begin carrying out its coordinating functions.
Congratulations and thanks go to John Kabashima, who retired from his position as extension horticultural advisor with the University of California’s Division of Agriculture and Natural Resources. John has devoted two years to building the alliances needed to make this happen.
Minnesota: New Funding for Research
In 2014, the Minnesota legislature created the Minnesota Invasive Terrestrial Plants and Pests Center at the University of Minnesota. The Center applies science-based solutions to protect the state’s terrestrial ecosystems and agricultural resources. It utilizes an allocation from the Environment and Natural Resources Trust Fund to support a competitive research grant program. The current funding level is $3.5 million. Recently funded projects include evaluating the role of fungi in protecting ash trees from emerald ash borer and disease, genetic control of invasive insects, and use of goats in invasive plant control
The Center’s draft list of priority insects, plant pathogens, and invasive plants includes numerous forest pests. Among the 40 insect species listed, 19 are forest pests. Those in the top ten include mountain pine beetle, emerald ash borer, European and Asian gypsy moths, two elm beetles, and Asian longhorned beetle. Nineteen of 39 plant pathogens are tree-killers. Among the top ten are Dutch elm disease, oak wilt, Japanese oak wilt, Annosum root rot, sudden oak death, thousand cankers disease, and white pine blister rust.
In both cases, the lists include species that are already present and those not yet in the state (or even on the continent).
Western Governors’ Association: Initiative on Biosecurity
Incoming chairman, Hawaiian Gov. David Ige, has announced a Biosecurity and Invasive Species Initiative. The Initiative will focus on the impacts that invasive species have on ecosystems, forests, rangelands, watersheds, and infrastructure in the West, and examine the role that biosecurity plays in addressing these risks. Governor Ige hosted a webinar on 12 July [not yet posted on the WGA website] on which he was joined by such experts as Chuck Bargeron, Center for Invasive Species & Ecosystem Health, University of Georgia; Pam Fuller, Program Leader, Nonindigenous Aquatic Species Database, USGS; Stinger Guala, Director of Biodiversity Information Serving Our Nation (BISON), USGS; Jamie Reaser, Executive Director, National Invasive Species Council; and Lori Scott, Interim President & CEO, and Chief Information Officer, NatureServe. The Association is sponsoring regional workshops on various components of the invasive species response on the following dates
Lake Tahoe, NV Sept 17-18 – prevention, control, management of established species
Cheyenne, WY Oct 11 -12 – restoration
Helena, MT Nov 14 – early detection and rapid response
Hawai`i Dec 9 & 10 – biosecurity and agriculture
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.
There is widespread agreement that the most important pathways for long-distance transport of non-native forest insects are wood packaging (crates, pallets, dunnage, etc.) and imports of live plants (which APHIS calls “plants for planting”). Sources (at end of blog): Aukema et al. 2010; Liebhold et al. 2012; Meurisse et al. 2018 and many others. See also my earlier blogs by scrolling down to the “categories” section and clicking on “wood packaging”.
According to Meurisse et al., by the middle of this decade, world maritime freight trade had reached about 10 billion metric tonnes, and air transport of cargo had reached 50 million tonnes – much of it packaged in wood.
As the world’s biggest importer, the United States receives about 27 million shipping containers each year (CBP to FT Campbell). A study carried out in 2005 – 2007 (Meissner et al. 2009) indicated that 75% of maritime shipments entering the U.S. contained wood packaging; 33% of air shipments contained wood packaging. These are significant increases over earlier estimates that put the number of containers entering the country at 25 million. An even older analysis estimated that 52% of incoming containers had wood packaging.
APHIS has recognized the pest risk associated with wood packaging for 20 years – since the Asian longhorned beetle was detected in a second city – Chicago – in 1998. APHIS and its Canadian counterpart (Canadian Food Inspection Agency) acted rapidly to adopt, first, domestic regulations governing wood packaging from China (in December 1998), then a regional standard for wood packaging, and finally to help bring about adoption of International Standard for Phytosanitary Measures (ISPM) No. 15 in 2002. A detailed description of these actions can be found in my report Fading Forests II available here.
However, as I have demonstrated often, ISPM#15 has reduced the threat – but insufficiently. Dr. Robert Haack and his coauthors (2014) found that of each thousand shipments containing wood packaging that enters the country, one harbors a quarantine pest. Applying this estimate to the current volume of incoming containers and the higher proportion containing wood packaging results in an estimate that up to 20,000 shipping containers containing infested wood packaging enter the country each year – or approximately 55 per day.
The actual approach rate might be less. There are two variables that I lack sufficient data to quantify.
First, a significant proportion of the incoming containers come from Mexico or Canada – our second and third largest trading partners. The risk of damaging pests arriving from our neighbors is less than the risk accompanying shipments from overseas – although it is not “0”. Several woodborers native to Mexico have been introduced to U.S. ecosystems and are killing trees in these new environments, e.g., goldspotted oak borer, walnut twig beetle, and soapberry borer (all described in write-ups here). It is true that these beetles were probably introduced to vulnerable parts of the U.S. in firewood rather than wood packaging. There are also reasons to be concerned about pest introductions from Canada. Threats arise from both non-native pests established in the country e.g., brown spruce longhorned beetle and European beech leaf weevil, and pests in shipments from off-shore origins that are re-packaged in Canada (Yemshanov et al. 2012 and my earlier blog from April 2017).
The second variable on which I lack data is the proportion of the 27 million containers that are transported by air, and are thus half as likely to contain wood packaging.
To account for these unknowns, I have nearly halved the number of shipping containers likely to transport pests from off-shore – so 14 million instead of 27 million. Again applying Haack’s estimate, the result is 10,500 shipping containers containing infested wood packaging entering the country every year – or approximately 29 every day.
Update with more precise data (August 24) :
Re: the two variables, I have found partial answers from a U.S. Department of Transportation website which provides data on imports of loaded chipping containers (in TEUs) for 68 ports. (For the website, go here – click on “trade statistics”, then “US Waterborne trade” (1st bullet)]
As of 2017, 22,360,941 loaded shipping containers entered the U.S. via maritime transport. Applying the estimate of 75% of these containers holding wood packaging, we find that slightly less than 17 million containers entered the country with wood packaging. Applying Robert Haack’s estimate that one in a thousand is infested with a quarantine insect, we anticipate that 17,000 of these containers were transporting a pest that threatens our country. That is 46 containers every day.
Ports which received the largest numbers of containers, according to the DoT database:
Long Beach/Los Angeles — 8.4 million containers
New York — 3.4 million containers
Savannah — 1.8
Norfolk — 1.2
Houston — 1 million containers
We need answers!
The point is, we don’t know how many pests are reaching the United States daily. Or if the current approach rate is significantly higher or lower than in the past. Despite my urging, APHIS has not undertaken a study to update Haack’s estimate – which is based on 2009 data. In the intervening nine years, several changes were made to ISPM#15 to make it more effective. The most important was restricting the size of bark remnants that may remain on the wood.
Also, we might hope that experience with implementing the standard has led to better compliance. Unfortunately, available data do not encourage belief that compliance has improved.
Customs and Border Protection (CBP) reports annually to the Continental Dialogue on Non-Native Forest Insects and Diseases on the number of import shipments with wood packaging that have been detected as not complying with ISPM#15. Over a period of eight years – Fiscal years 2010 through 2017 – CBP detected nearly 24,000 non-compliant shipments. While most (17,413) of the non-compliances were crates or pallets that lacked the required mark showing treatment in accordance with ISPM#15, in 6,388 cases the wood packaging actually harbored a pest in a regulated taxonomic group. This works out to about 800 infested shipments detected each year.
By comparing Dr. Haack’s estimate with the CBP data, I estimate that Customs is detecting and halting the importation of four to eight percent of the shipments that actually contain pest-infested wood. Since CBP inspects only about two percent of incoming shipments, this detection rate demonstrates the value of CBP’s program to target likely violators – and deserves praise. But it is obviously too low a “catch” rate to provide an adequate level of protection for our forests.
Indeed, using the older, lower estimates of both numbers of shipping containers and the proportion that contain wood packaging, Leung et al. 2014 concluded that continuing to implement ISPM#15 at the efficacy level described by Haack et al. would result in a tripling of the number of non-native wood-boring insects introduced into the U.S. by 2050.
CBP inspector views Cerambycid larvae found in wood packaging that bears ISPM#15 stamp
Closer examination of the data raises more troubling questions. On average, 97% of the 6,388 shipments containing infested wood pieces detected by CBP were found in wood that bore the ISPM#15 stamp indicating that it had been treated. The proportion of infested shipments bearing the stamp has not changed over the past eight years. This is alarming and we need to understand the reason. Does this finding indicate widespread fraud? I understand that most inspectors believe this is the cause. Other possible explanations are accidental misapplication of the treatments or the treatments simply not working as expected. APHIS researchers have found that larvae from wood subjected to methyl bromide fumigation were more likely to survive to adulthood than those intercepted in wood that had been heat treated (Nadel et al. 2016). Does this indicate that methyl bromide fumigation is less effective? What effort is APHIS making to determine which of these explanations is correct?
Certain countries have a long-standing record of non-compliance with ISPM#15. APHIS’ database of pest interceptions on wood packaging over the period Fiscal Year 2011 to FY 2016 contains 2,547 records of insect detections from dozens of countries. The countries of origin with the highest numbers of shipments detected to have pests present were Mexico, China, Italy, and Costa Rica. These numbers reflect in part the huge volumes of goods imported from both Mexico and China. But China and Italy stand out for their poor performance. (The U.S. does not regulate – or inspect! – wood packaging from Canada; see blog here.)
Meissner et al. say that as of a decade ago, Chinese shipments were only half as likely to be enclosed in wood packaging as are shipments from other exporters. Yet shipments from China still rank second in the number of non-compliant shipments; they make up 11% of all interceptions. In part, the data reflect inspection priorities: due to the great damage caused by Asian insects to North American trees and the past record of poor compliance, CBP targets shipments from China for more intense scrutiny. Still, the high number of detections reflects continuing non-compliance by Chinese exporters. And remember – the U.S. and Canada began requiring treatment of wood packaging from China at the end of 1998 – nearly 20 years ago! [Feb 17 blog]
We don’t import a lot of goods from Italy – but Italian shipments of decorative stone and tile have always been plagued by high levels of pests in accompanying wood packaging. Indeed, more pests have been found in wood supporting tiles and stone than any other type of commodity in 24 of the 25 years preceding 2014 (Haack et al. 2014).
What is APHIS doing to pressure these countries to improve their compliance? As I blogged in October, link the Bureau of Customs and Border Protection began imposing a financial penalty on first-time violators in November 2017. Since interception data do not provide an adequate measure of the pest approach rate (see Haack et al 2014 for an explanation), APHIS should commission an analysis of Agriculture Quarantine Inspection Monitoring data to determine the pest approach rate before and after the CBP action in order to determine whether the more aggressive enforcement has led to reductions in non-compliant shipments at the border.
What Can Be Done to Slow or Eliminate this Pathway?
I reiterate my call for holding foreign suppliers responsible for complying with ISPM#15. One approach is to penalize violators. Now that the Bureau of Customs and Border Protection has toughened its enforcement, the U.S. Department of Agriculture should drop its decade-old policy of allowing importers to accumulate five (detected) violations in a calendar year before applying the civil penalties authorized by the Plant Protection Act.
Another step APHIS should take would be to prohibit use of packaging made from solid wood (boards, 4 x 4s, etc.) by foreign suppliers which have a record of repeated violations over the 12 years that ISPM#15 has been in effect – or the 19 + years for exporters from Hong Kong & mainland China. Officials should allow continued imports from those same suppliers as long as they are contained in other types of packaging materials, including plastic, metals, fiberboards …
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
Haack, R. A., K. O. Britton, E. G. Brockerhoff, J. F. Cavey, L. J. Garrett, M. Kimberley, F. Lowenstein, A. Nuding, L. J. Olson, J. Turner, and K. N. Vasilaky. 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:e96611.
Hulme, P.E. 2009. Trade, transport and trouble: Managing invasive species pathways in an era of globalization. Journal of Applied Ecology 46:10-18
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; available from Resource Gate
Klapwijk, M.J., A.J. M. Hopkins, L. Eriksson, M. Pettersson, M. Schroeder, A. Lindelo¨w, J. Ro¨nnberg, E.C.H. Keskitalo, M. Kenis. 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
Koch, F.H., D. Yemshanov, M. Colunga-Garcia, R.D. Magarey, W.D. Smith. 2011. Potential establishment of alien-invasive forest insect species in the United States: where and how many? Biol Invasions (2011) 13:969–985
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
Levinson, M. The Box: How the Shipping Container Made the World Smaller and the World Economy Bigger Princeton University Press 2008
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. www.frontiersinecology.org
Meissner, H., A. Lemay, C. Bertone, K. Schwartzburg, L. Ferguson, 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 USDA APHIS Plant Epidemiology and Risk Analysis Laboratory
Meurisse, N. D. Rassaati, B.P. Hurley, E.G. Brockerhoff, R.A. Haack. 2018. Common Pathways by which NIS forest insects move internationally and domestically. Journal of Pest Science. https://doi.org/10.1007/s10340-018-0990-0
Nadel, H., S. Myers, J. Molongoski, Y. Wu, S. Linafelter, A. Ray, S. Krishnankutty, A. 2016. Identificantion of Port Interceptions in Wood Packaging Material Cumulative Progress Report, April 2012 – August 2016
Yemshanov, D., F.H. Koch, M. Ducey, K. Koehler. 2012. Trade-associated pathways of alien forest insect entries in Canada. Biol Invasions (2012) 14:797–812
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.
The number of new pathogens discovered each year on 131 focal host plant species in New Zealand (closed circles) and the mean annual rate of pathogen arrival estimated from the model (solid blue line), with shading showing the 95% credible interval.
Benjamin A. Sikes and several coauthors (article available here; open access!) find that targetted biosecurity programs can reduce the establishment of nonnative pathogens even while global trade and travel continue to increase.
The study relies on data from New Zealand because that country has more than 150 years of data on phytosanitary policies and pathogen introductions. Do other countries have data that would support a comparative study in order to test the authors’ conclusions more generally?
The study is unusual in analyzing introductions of a variety of forms of pathogens (fungi, oomycetes, and plasmodiophorids) rather than invertebrates. Pathogens pose significant plant health risks but are notoriously difficult to detect. The study used data on plant-pathogen associations recorded in New Zealand between 1847 and 2012. It focused on hosts in four primary production sectors: crops (46 species, including wheat, tomatoes, and onions); fruit trees (30 species, including grapes, apples, and kiwifruit); commercial forestry (42 species, including pines and eucalypts); and pastures (13 species of forage grasses and legumes). In total, 466 pathogen species for which the first New Zealand record was on one of these 131 host plants were included in the study. The pathogens were assumed to have arrived on imports seeds or fresh fruits of plants in the same family as the 131 hosts in the various production sectors.
After calculating each pathogen’s probable date of introduction, the authors compared those dates to contemporaneous levels of imports and incoming international travellers. Sikes et al. applied statistical techniques to adjust their data to the fact that detection of pathogens is particularly sensitive to variation in survey effort.
Findings:
The annual arrival rate of new fungal pathogens increased exponentially from 1880 to ~1980 in parallel with increasing import trade volumes. Subsequently rates stabilized despite continued rapid growth in not only imports but also in arrivals of international passengers.
However, there were significant differences among the four primary production sectors.
Arrival rates for pathogens associated with crops declined beginning in the 1970s but slightly earlier for those associated with pasture species. These declines occurred despite increasing import volumes.
Arrival rates of pathogens that attack forestry tree species continued to increase after 1960.
Arrival rates for pathogens that attack fruit tree species remained steady while import volumes rose steadily
Sikes et al. attribute these contrasting trends between production sectors to differences in New Zealand’s biosecurity efforts. They record when phytosanitary restrictions targetting the four sectors were adopted and link those changes to reductions in numbers of pathogens detected a decade or so later. They conclude that targetted biosecurity can slow pathogen arrival and establishment despite increasing trade and international movement of people.
Regarding the contrasting situation of the forestry and fruit tree sectors, Sikes et al. note that while phytosanitary inspections of timber imports was initiated in 1949, it focussed primarily on invertebrate pests. In addition, surveys for pathogens on fruit tree and forestry species were less robust than in the cases of crop and pasture species, and the peak survey effort occurred several decades later – in 1980 for fruit trees, 2000 for forestry species.
Furthermore, pathogens of forestry and fruit tree species can be introduced on types of imports other than seeds and fresh fruits, including soil and live plant material (e.g., rootstock) and untreated wood products.
Sikes et al. say there is no evidence of slowed pathogen arrival rates resulting from imposition of post-entry quarantine to live plant material beginning in the 1990s. I find this very troubling. Post-entry quarantine is a high-cost strategy. Still, several plant pathologists have advocated adoption of this strategy because they believed it would be sufficiently more effective in preventing introductions of – especially! – pathogens as to be worthwhile. Do others have data with which to add to our understanding of this disturbing phenomenon?
The authors suggest that introductions of tree-attacking pathogens on rising imports of wood packaging might have swamped decreases in introductions via other vectors. They consider that implementation of International Standard for Phytosanitary Measures (ISPM) No. 15 in 2002 means it is too early to see its impact in detection data. As I have blogged several times, implementation of ISPM#15 by the United States, at least, has reduced presence of detected pests – primarily insects – by 52%. Little is known about the presence of pathogens on wood packaging – according to some experts, inspectors rarely even look for pathogens. So I think the authors’ suggestion might not fully explain the continuing introduction of pathogens that attack tree species used in plantation forestry in New Zealand.
Prof. Michael Wingfield of South Africa has written numerous articles on the spread of pathogens that attack Eucalyptus on seeds imported to establish plantations in various countries; one such article is available here. This seems a more likely explanation to me.
The study’s analysis demonstrated that the overall rate of non-native fungal pathogen establishment in New Zealand was more strongly linked to changes in import trade volume than to changes in numbers of international passengers arriving on the islands. Although Sikes et al. don’t explicitly raise the question, they note that New Zealand has put considerable effort into screening incoming people – which appears from these data to have a smaller payoff than imposing phytosanitary controls on imports.
Recent declines in surveys mean the authors must estimate current pathogen arrival rates. The data gaps exacerbate the inevitable uncertainty associated with the time lag between when an introduction occurs and when it is detected. They estimate that an average of 5.9 new species of fungal pathogens per year have established on the focal host plant species since 2000. They estimate further that 55 species of pathogens are present in New Zealand but have not yet been detected there.
I am quite troubled by the reported decline in New Zealand’s postborder pathogen survey efforts since about 2000. This appears very unwise given that the risk of new introductions of pathogens that attack fruit and forestry trees continues – or even rises! Indeed, scientists associated with the forestry industry note the risk to Douglas-fir and Monterrey (Radiata) pine plantations from the pitch canker fungus Fusarium circinatum – which could be introduced on imported seeds, nursery stock, and even wood chips. Radiata pine makes up 92% of softwoods planted – and exotic softwoods constitute 97% of the plantation forestry industry.
Furthermore, non-native pathogens threaten New Zealand’s unique forest ecosystems. Since this study focused on non-native plant hosts, it does not address the risk to native forest species. However, the threat is real: Kauri trees – the dominant canopy species in some native forest types – is suffering from a dieback caused by an introduced Phythopthora. Also, two other pathogens threaten the many trees and shrubs in the Myrtaceae family found in New Zealand – Puccinia rust (which is established in Australia but not New Zealand) or the Ceratocystis fungi causing rapid ohia death – both threaten native forests in Hawai`i, as discussed in a recent blog.
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.
In mid-May, the House Committee on Appropriations adopted two bills crucial to funding efforts to counter tree-killing non-native insects and diseases. Please let them know you are grateful.
APHIS funding
The Agriculture appropriations bill funds APHIS (and other USDA agencies) for Fiscal Year 2019 (which begins on October 1). The new bill provides a total of $998,353,000 to APHIS, an increase of $16.4 million above the FY18 level and $259 million above the Administration’s request. ( I blogged about the Administration’s alarming request here.) You can find the bill here; the more informative report is posted here. Use search words to find specific APHIS programs.
The pest-related funding is apportioned among several areas:
Tree and Wood Pest Program. Unlike in previous years, the House bill does not cut funds for this program – which funds efforts to eradicate or contain the Asian longhorned beetle, emerald ash borer, and European gypsy moth. Instead, it maintains funding at the FY18 level of $54 million. Under the circumstances, this is good news. Thank you for your efforts to educate members of the House subcommittee on agricultural appropriations about this crucial program! (In past years, we relied on the Senate to restore funding for the Tree and Wood Pest Program.)
Specialty Crop Pests Program. The House increased funding by $10.8 million here, and specified that $15 million target the spotted lanternfly. This recently detected Asian leafhopper is spreading in southeastern Pennsylvania and was recently confirmed in Virginia’s Shenandoah Valley. It is a pest of native hardwood trees as well as of orchard and other crops.
Also, the Committee used its report to stress several concerns:
Access to emergency funding. In the report, the House Appropriations Committee reiterates its longstanding instruction that the USDA Secretary continue to use his authority to transfer funds from the Commodity Credit Corporation. They support using these funds – above and beyond appropriated funds – for the arrest and eradication of animal and plant pests and diseases that threaten American agriculture.
Brown Apple Moth vs. Emerald Ash Borer. Interestingly, the House Appropriations Committee encourages APHIS to engage state and international regulatory bodies as it moves to deregulate the light brown apple moth. The Committee expresses concern that if APHIS simply withdraws federal regulation without the necessary work with other officials, it will shift, not reduce, the regulatory burden. Then growers would carry the burden of preventing spread of the pest. I wish the Committee had made the same statement vis a vis the emerald ash borer! APHIS also plans to stop regulating this insect which continues to threaten still-uninvaded portions of the United States and Mexico.
Micornesia and Hawai’i. The Committee also instructs the Secretary of Agriculture to report to both the House and Senate Committees on Appropriations its progress implementing the Regional Biosecurity Plan for Micronesia and Hawai`i. This plan combines efforts by the U.S. Department of Defense, Department of the Navy, and the island governments to prevent transport of invasive species as a consequence of relocating military personnel from a base in Okinawa, Japan. More information is available here.
Forest Service funding
The Interior appropriations bill funds the US Forest Service (as well as Interior Department and Environmental Protection Agency).
Forest Health Management Program. The bill provides an increase of $19.5 million above FY18 levels for the forest health management program ($30 million above the Administration’s request). The Committee instructs the Forest Service to “work in concert with Federal agencies, States, and other entities to prioritize the allocation of these funds to address the greatest threats.” The emerald ash borer, “bark beetle” (which ones?) and cogon grass are expressly mentioned. The report is posted here. (It is unclear what actions the Forest Service is expected to take on the EAB, since regulations intended to curtail people from moving infested wood will soon be dropped by APHIS. The Forest Service could support breeding of ash trees resistant to the beetle.)
Forest Service Research. The Interior appropriations bill also maintained funding for Forest Service research at the FY18 level of $297 million – rather than cutting it to $259 million as advocated by the Administration. The Committee has called for the USFS to act within one year to “strengthen” its research program. The Committee expressly avoids endorsing several priorities advocated by Members of Congress while waiting for the Forest Service to implement this instruction.
If your representative is a member of the House Appropriations Committee (members listed here), please thank them for supporting APHIS’ and USFS’ programs. These funding increases shift several years of decline and are a true win for protecting our forests from non-native insects and pathogens!
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.
As you might remember, the Center for Invasive Species Prevention and the Vermont Woodland Owners Association last year proposed several amendments to the Farm Bill that we hoped would strengthen the U.S. Department of Agriculture’s programs on non-native insects, plant pathogens, and invasive plants. These proposed amendments are here and here.
Two of our amendments sought to strengthen funding for long-term strategies to counterpests and restore pest-depleted tree species to the forest. We intended these proposals to be implemented together. They were put forward as two proposals only because they fell into different sections, called “titles”, of the Farm Bill.
Our first proposal would create a grant program managed by the National Institute of Food and Agriculture (NIFA) to fund research focused on biocontrol and genetic manipulation of the pests; enhancement of host-resistance mechanisms for tree species; and development of other strategies for restoration. U.S. government agencies, state cooperative institutions, academic institutions with a college of agriculture or wildlife and fisheries, and non-profit organizations would all be eligible for funding.
Our second proposal would provide long-term funding to a similar array of organizations to support research into and deployment of strategies for restoring pest-resistant genotypes of native tree species to the forest. We suggested funds be drawn from the McIntyre-Stennis program. Successful grant applicants would be required to integrate several components into a cohesive forest restoration strategy:
Collection and conservation of native tree genetic material;
Production of sufficient numbers of propagules of pest-resistant native trees to support landscape scale restoration;
Site preparation in native trees’ former habitat;
Planting of native tree seedlings; and
Post-planting maintenance of the trees.
Furthermore, priorities for competitive grants issued by this second fund would be based on the level of risk to forests in the state where the activity would take place, as determined by the following criteria:
Level of risk posed to forests of that state by non-native pests, as measured by such factors as the number of such pests present there;
Proportion of the state’s forest composed of species vulnerable to non-native pests present in the United States; and
Pests’ rate of spread via natural or human-assisted means.
Several coalitions presented these two proposals – in various forms – to the House and Senate Agriculture committees earlier this year.
ACTION IN THE HOUSE OF REPRESENTATIVES
The Stefanik Amendment
In the House, Representative Elise Stefanik (R-NY21) inserted a modified version of CISP’s proposed amendments into the Farm Bill (H.R. 2) . Ms. Stefanik’s speech on the House floor introducing her amendment, and support of that amendment by Rep. Glenn Thompson of Pennsylvania and Agriculture Committee Chairman K. Michael Conaway (R-TX) can be heard here; scroll to time 25.16
The Stefanik amendment includes some of the key provisions advocated by CISP but it also differs in significant ways. That is, it relies on an existing grant-making program, the Competitive Forestry, Natural Resources, and Environmental Grants program. This program funds proposals pursuing numerous purposes, including pest management and genetic tree improvement. Rep. Stefanik’s amendment adds a new purpose, restoring forest tree species native to American forests that have suffered severe levels of mortality caused by non-native pests. It is unclear whether this approach will significantly increase resources available for breeding trees resistant to non-native pests.
Another difference is that institutions receiving funds would have to demonstrate that their activity is part of a broader strategy that includes at least one of the following components:
1) Collection and conservation of genetic material;
2) Production of sufficient numbers of propagules to support the tree’s restoration to the landscape;
3) Site preparation of former native tree habitat;
4) Planting; and
5) Post planting maintenance
The original CISP proposal required any funded program to incorporate all of these components.
The Stefanik amendment would award grants based on the same three criteria proposed by CISP.
While we are disappointed that research underlying tree restoration has merely been added to an already-long list of purposes under the Competitive Forestry, Natural Resources, and Environmental Grants program, this approach might be the best we can hope for. There had been considerable opposition to our proposal because it would have changed the formula under which McIntire-Stennis funds are apportioned to the states. Adopted in 1962, the existing formula is based on each state’s
1) area of non-Federal commercial forest land;
2) volume of timber cut annually;
3) total expenditures for forestry research from non-Federal sources;
4) base amount distributed equally among the States.
The Faso Amendment
The House also accepted an amendment sponsored by Rep. John Faso (R-NY19) that would require APHIS and the US Forest Service to collaborate on surveillance to detect newly introduced tree-killing pests. The agencies would also report to Congress by 2021 on which pests are being detected on imports of wood packaging and living plants (APHIS’ so-called “plants for planting”) and the geographic origins of those pests. Rep. Faso’s speech introducing the amendment and supportive statements by Reps. Thompson and Conaway can be heard here; scroll to time 32 (immediately after the Stefanik amendment).
The Welch Bill
Meanwhile, as I blogged earlier, Rep. Peter Welch (D-VT) has introduced a separate bill (H.R. 5519) that contains modified versions of several CISP proposals.
Rep. Welch’s bill would do two things: strengthen APHIS’ access to “emergency” funds to respond to invasive pests, and create a competitive grant program to support research on biological control of plant pests or noxious weeds, enhancing host pest-resistance mechanisms, and other strategies for restoring tree species. These studies must be part of comprehensive forest restoration research. Eligible institutions would include federal and state agencies, academic institutions, and nonprofit organizations. Funding would come from a USDA corporation, the Commodity Credit Corporation so they would not be subject to annual appropriations.
The House has taken no action on Rep. Welch’s bill.
THE CURRENT STATUS OF THE FARM BILL – AND CISP’s BOTTOM LINE
On 17 May, the House of Representatives failed to pass the Farm Bill. No Democrats voted for the bill. About 30 Republicans also voted against the bill – not because they objected to its contents, but because they wanted to force a vote on an immigration bill. House leaders now promise a new vote on the Farm Bill on June 22nd.
Is this good news? As I said, it is complicated! The House bill contains several provisions to which there is significant opposition. The most controversial is a requirement that recipients of food stamps prove that they are working. Other provisions – which have not received much attention in the media, would:
Allow the U.S. Forest Service and the Interior Department’s Bureau of Land Management to decide for themselves whether an activity might “jeopardize” an endangered species (eliminating the need to consult with the U.S. Fish and Wildlife Service or National Marine Fisheries Service) (Section 8303);
Allow the U.S. Forest Service and Bureau of Land Management to avoid preparing an environmental assessment under the National Environmental Policy Act (NEPA) for a long list of actions which currently must be assessed. That is, they could claim a “categorical exclusion” when taking a wide variety of “critical” actions aimed at addressing several goals. These include countering insect and disease infestations, reducing hazardous fuel loads, protecting municipal water sources, improving or enhancing critical habitat, increasing water yield, expediting salvage of dead trees following a catastrophic event, or achieving goals to maintain early successional forest. These “categorical exclusions” would apply to projects on up to 6,000 acres. (Sections 8311 – 8320); and
Require the EPA Administrator to register a pesticide if the Administrator determines that the pesticide, when used in accordance with widespread and commonly recognized practices, is not likely to jeopardize the survival of a species listed under the Endangered Species Act or to alter critical habitat. Unlike under current law, the Administrator would not be required to consult with the U.S. Fish and Wildlife Service or National Marine Fisheries Service when making such determinations (Section 9111).
The Endangered Species Act, adopted almost unanimously in 1973, requires such “consultations” because experience had shown that agencies proposing projects tended to underestimate the damage that they might cause to imperiled species. NEPA is one of the foundational statutes of U.S. environment protection; it was adopted in 1970. Finally, the EPA Administrator is supposed to decide whether to allow pesticide use based on science, per a much weaker but still important environmental protection statute, the Federal Insecticide, Fungicide, and Rodenticide Act (originally adopted in 1910; significantly amended in 1972).
Is getting an imperfect and partial program that might stimulate breeding of tree species resistant to invasive pests worth accepting this level of damage to fundamental environmental programs?
I don’t think so.
We don’t yet know what the Senate will do. We hope the Senate bill will support strong conservation programs – including strengthening APHIS and research into and application of long-term strategies such as resistance breeding – while not undermining the foundations of our Nation’s conservation and environmental programs.
Meanwhile, the House should rewrite the Farm Bill to remove the objectionable provisions.
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.
last year’s leaves showing symptomatic striping (F.T. Campbell)
Back in December I blogged about beech leaf disease, a disease affecting American beech in northeastern Ohio and neighboring parts of Pennsylvania and New York, as well as across Lake Erie in Ontario.
[For more information and photos of symptoms, visit
Scientists do not know what is causing the disease. So far it’s only clear that it appears to have been introduced to a single site and is spreading. At the beginning of May I participated in a workshop providing the most recent information on beech leaf disease.
workshop participants (budbreak was later than usual, so we could not observe deformed leaves) (F.T. Campbell)
Over the past three or four years, scientists have tried hard to understand the disease, its causes, and its likely prognosis. For example, scientists from the U.S. Department of Agriculture and the State of Ohio have looked for insects, fungal pathogens, bacteria, viruses, nematodes, phytoplasmas – all without finding a causative agent. Attention is currently focused on a previously undescribed nematode in the Litylenchus genus. The only other species in this genus is a foliar feeder found in New Zealand. Studies continue, with most scientists tackling the problem without special funding.
Beech is a very important component of the forests of northeastern Ohio. Beech ranks third in number of stems per acre; second for “shrubs”. Consequently, scientists working for Lake Metroparks and Cleveland Metroparks continue to monitor spread of the disease and its impacts. Symptoms – deformed leaves – were first detected in 2012. In 2017, the results of a long-term vegetation monitoring project revealed that of 307 plots with beech present, 154 had symptomatic trees. Of the symptomatic plots, 49% of beech stems were affected. While initially only small trees had been killed, more recently some larger ones have died and others bear only very few leaves. Leaves with light, medium, or heavy symptoms of infection – as well as asymptomatic leaves – can occur on the same branch of an individual tree.
The disease seems to spread faster between stems along the interlocking roots of beech clone clusters.
Weather does not appear to be a factor, as the disease has spread every year despite great variations in heat and cold as well as levels of moisture.
Preliminary versions of a mathematical model of the disease’ spread indicates that approximately 90% of monitoring plots deployed across the full 24,000 acres of Cleveland Metropark system will be infected within 10 years.
Cleveland Metroparks has initiated intensive monitoring of a subset of 13 plots in order to clarify the disease’s impact. Monitoring revealed a 4% mortality rate from 2015 to 2017. More than half of these plots now have dead beech that had previously been symptomatic. Most are small trees less than 4.9 cm dbh. Efforts to obtain funding from the USFS Forest Health program have so far failed.
The disease – whatever its cause! – appears to be moved by trade in nursery plants. An Ontario retailer received – and rejected – a shipment of diseased beech from an Ohio nursery. Lake County, Ohio, has many nurseries that grow and ship European beech (which can also be infected by beech leaf disease). These nurseries are reported to be cooperating with Ohio authorities. No official entity has imposed regulatory restrictions – not any of the states or provinces with the disease present or threatened by it; nor USDA APHIS or the Canadian Food Inspection Agency (CFIA).
Another threat to beech also not under regulation
CFIA has also not imposed a federal quarantine on another non-native pest killing beech, the European leaf-mining weevil, Orchestes fagi. First discovered in Halifax in 2012 – probably 5 years after its introduction – it has since spread throughout Nova Scotia. The weevil kills beech over 3 – 5 years.
New information added in June: according to Meurisse et al. (2018), the weevil overwinters under the bark of beech and trees that are not hosts, so it can be transported by movement of firewood and other forms of unprocessed logs and branches. [Meurisse, N. D. Rassaati, B.P. Hurley, E.G. Brockerhoff, R.A. Haack. 2018. Common Pathways by which NIS forest insects move internationally and domestically. Journal of Pest Science. https://doi.org/10.1007/s10340-018-0990-0]
The Importance of American Beech – and Protecting It
Beech is an extremely important tree in northern parts of the United States and Canada east of the Great Plains. It is co-dominant (with sugar maple) in the Northern Hardwood Forest [see two maps]. A summary of the species’ ecological importance can be found in Lovett et al. 2006. Forest Ecosystem Responses to Exotic Pests and Pathogens in Eastern North America. BioScience Vol. 56 No. 5.
native range of American beech; USFS map
Consequently, I am most distressed by the lack of attention to these new threats to the species. It is true that regulating an unknown disease agent (as would be the case with beech leaf disease) stretches traditional policy practice and possibly legal authorities. Furthermore, it has not yet been demonstrated that the disease can kill mature beech. However, neither of these caveats applies to the weevil, which is an identified species that has been documented to kill mature trees.
U.S. phytosanitary officials (the National Plant Board) will meet in Cleveland (!!) in August. Will the several state officials and their APHIS colleagues discuss how to address this new threat? Will any funds be made available to expand efforts to understand the disease, its spread, and possible measures to curtail it?
healthy beech, northern Virgina (F.T. Campbell)
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.
Worsening Threats to Hawaii’s Rich – and Rare — Native Forests
As I have written in previous blogs (October 2015; October 2016), the beautiful ‘ōhi‘a lehua (Metrosideros polymorpha) tree is ecologically and culturally the most important tree n the Hawaiian Islands. ‘Ōhi‘a trees dominate approximately 80% of Hawai`i’s remaining native forest. Loss of the species could result in significant changes to the structure, composition, and, potentially, the function, of forests on a landscape level. ‘Ōhi‘a forests are home to the Islands’ one native terrestrial mammal (Hawaiian hoary bat) as well as about 100 plant species listed as endangered by the U.S. Fish and Wildlife Service. Also 30 species of forest birds – in particular, the unique endemic honeycreeper subfamily — depend on ‘ōhi‘a. Eighteen of 19 extant Hawaiian honeycreepers in the main Hawaiian islands, including 12 of 13 bird species listed as endangered by the U.S. Fish and Wildlife Service, depend on ‘ōhi‘a for critical habitat.
Unfortunately, the threat to ‘ōhi‘a trees from three fungi appears to be rising.
“Rapid ‘ōhi‘a death” is caused by two fungi, Ceratocystis lukuohia and C. huliohia (formerly considered to be strains of Ceratocystis fimbriata). Rapid ‘ōhi‘a death has spread since 2010 to most districts of one island: Hawai`i or the “Big” Island. The total area affected is 135,000 acres. Still, most ʻōhiʻa forest on Hawai`i is still healthy, and the disease has not yet been found on any of the other islands. Scientists have begun exploring trees’ varying susceptibility and the possibility of breeding more resistant trees to be used for restoration. For more information, read the recently updated description here.
Ōhi‘a trees are also under attack by a third introduced fungus, called ‘ōhi‘a rust, guava rust, or myrtle rust. This is caused by Austropuccinia psidii (formerly named Puccinia psidii). Ōhi‘a rust has been established on all the Hawaiian islands since 2005. Until recently, it had caused little damage to ‘ōhi‘a – although it attacks several additional native plant species and has devastated the endangered endemic plant Eugenia koolauensis. This shrub can reproduce now only in nurseries where it can be treated for the fungus. In late 2017, an outbreak of the disease caused widespread defoliation and mortality of ‘ōhi‘a across hundreds of acres in at least four locations on windward portions of two islands, O‘ahu and Moloka‘i. It is not yet known whether this new damage resulted from introduction of a new, more virulent strain or from a period of unusually wet weather creating more favorable conditions for the fungus. For more information, read the recently updated description here. (Myrtle rust threatens plants in the Myrtaceae family across the Pacific; more than 450 species have been identified as hosts. Some species in Australia have been severely affected.)
Severe Attacks on Redbay and other Laurels in the Southeast.
Since the turn of the century, redbay trees (Persea borbonia) in coastal regions of the Southeast have been dying because of laurel wilt disease. This is caused by the fungus Raffaelea lauricola, which in turn is vectored by the redbay ambrosia beetle (Xyleborus glabratus). Both the beetle and disease have spread rapidly since there were detected in 2002 near Savannah, Georgia. The disease now is found in eight states, reaching from eastern North Carolina south along most of the Florida peninsula; across the Gulf states with several locations in Alabama and Mississippi; and to isolated outbreaks in Louisiana and Texas. Already an estimated 320 million trees – nearly one-third of all redbays – have been killed. Mortality is highest where the disease first became established: Georgia (two-thirds of redbays killed), South Carolina (42% of redbays killed), and Florida (36% of redbays killed). In contrast, redbay mortality appears to be quite low in Alabama and Mississippi although mortality caused by disease might have been masked by application of fire or other silvicultural practices.
Other forest trees and shrubs in the Lauraceae family are also at risk. These include swamp bay (Persea palustris), which contribute greatly to the biological diversity of the “tree islands” scattered through the Everglades; sassafras (Sassafras albidum), which occupies a large range reaching into Michigan and southern New England; and two rare species – pondspice (Litsea aestivalis) and the federally listed pondberry (Lindera melissifolia). Northern spicebush (Lindera benzoin), another shrub in the Lauraceae family, does not attract the beetle so it is unlikely to sustain disease. In the West, California bay laurel has been determined by laboratory studies to be vulnerable.
Redbay is important to wildlife and has some use in horticulture. However, most attention has focused on the threat to avocados (Persea americana); the disease was detected in commercial orchards in 2012.
Concerned about loss of this ecologically important tree, scientists have begun efforts to breed redbays that are resistant to, or tolerant of, the disease. In addition to efforts by university scientists, the newly formed consortium Forest.Health (https://forest.health/) has listed redbay as a high priority for resistance breeding. For more information, read the updated description here.
initial damage caused by Kuroshio shot hole borer in Tijuana River Valley; I lack access to photos of recovery. Photo by John Boland
Hope in southern California – possible ecological limits to shot hole borer / fungal disease
John Boland, an ecologist who has studied southern California riparian wetlands for decades, reports that willows in the Tijuana River are recovering from attack by the Kuroshio shot hole borer and the fungi it vectors. After two years, the beetle-vectored disease had infested 88% of the willows in the valley (a total of 355,510 trees). An estimated 24% of the willows had been killed (95,791 trees). Nearly all of the infested and killed trees grew in the wettest parts of the riparian forests. (Photo above illustrates damage at this stage of the invasion.)
However, 71,280 of the willow trees have resprouted. By late 2017, these resprouts had created a new forest canopy that was about 5 meters tall. (Previously, the canopy had been about 20 meters tall). The median rate of infestation of these resprouting willows was 6% in 2017, down from 97% in 2015-2016. Some insect boring holes have healed.
In contrast, willows growing in drier parts of the valley were rarely attacked initially, but are now increasingly infested. In 2017, the median infestation rate was 78%, up from 9% in 2015-16. However, few trees have been killed.
Dr. Boland believes that the severity of the initial attack reflected the vulnerability of “soft trees”. Trees growing in the wetter parts of the Tijuana River Valley are inundated by sewage from the Mexican city. As a result of this artificial fertilization, they grow quickly and their wood is less dense.
For more information about the Kuroshio and phytophagous shot hole borers and their associated fungi, read the description here.. Dr. Boland’s study has been made available to participants in the southern California emerging forest pest groups but I cannot find a publicly available source on the Web.
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.
citrus longhorned beetle – entered country several times in imported bonzai plants
After about 20 years, APHIS has finalized important changes to the regulations which govern imports of living plants (what they call “plants for planting”; the regulation is sometimes called “the Quarantine 37” rule). The new regulation takes effect on April, 18, 2018.
I congratulate APHIS on this important achievement!
[Twenty years is a long time – so changes happen. When APHIS released its Advance Notice of Proposed Rulemaking (ANPR) in December 2004 and its proposed rule in April 2013, I was employed by The Nature Conservancy and submitted comments for that organization. I will refer to those earlier comments in this blog. However, I now represent the Center for Invasive Species Prevention, so my comments here on the final regulations reflect the position of CISP, not the Conservancy.]
APHIS’ 2004 ANPR came after years of preparation. Then, more than eight years passed until the formal proposal was published on April 25, 2013. Comments were accepted from the public until January 30, 2014. During this nine-month period, 17 entities commented, including producers’ organizations, state departments of agriculture, a foreign phytosanitary agency (The Netherlands), private citizens, and The Nature Conservancy. [You can view the ANPR and proposal, comments on these documents, and APHIS’ response here — although you need to click on “Restructuring of Regulations on the Importation of Plants for Planting” and then “Open Docket Folder” to pursue the older documents.]
In the beginning, APHIS had a few goals it hoped to achieve: to allow the agency to respond more quickly to new pest threats, to apply practices that are more effective at detecting pests than visual inspection at points of import, and to shift much of the burden of preventing pest introductions from the importer and APHIS to the exporter.
Progress has been made toward some of these goals outside this rule-making. APHIS instituted a process to temporarily prohibit importation of plants deemed to pose an identifiable risk until a pest risk assessment has been completed (the NAPPRA process). APHIS has further enhanced its ability to act quickly when a pest risk is perceived by relying increasingly on “Federal Orders”.
At the same time, APHIS participated actively in efforts by international phytosanitary professionals to adopt new “standards.” These define a new approach to ensure that plants in international trade are (nearly) pest-free. Both the North American Plant Protection Organization’s regional standard (RSPM#24) and the International Plant Protection Organization’s global standard (ISPM#36) envision a system under which countries would no longer rely primarily on inspections at ports-of-entry. Instead, they would negotiate with the supplier or exporting country to develop programs to certify that growers’ pest management programs are effective. Both standards detailed: 1) how the place of production might manage pest risk and ensure traceability of plants; 2) how the importing and exporting countries might collaborate to administer the program; 3) how audits (including site visits) would ensure the program’s efficacy; and 4) what actions various parties might take in cases of noncompliance.
It was hoped that these international standards would lead to widespread adoption of “integrated pest management programs” composed of similar requirements – similar to the impact of ISPM#15 for wood packaging. However, living plants are more complex pest vectors than the wooden boards of crates and pallets, so each country was expected to negotiate its own specific programs – something not encouraged for wood packaging.
APHIS’ decades-long effort to amend its regulations is warranted because of the high risk of non-native insects and – especially – pathogens being introduced via international trade in living plants. U.S. examples include white pine blister rust, chestnut blight, dogwood anthracnose, and sudden oak death (all described briefly here )
According to Liebhold et al. 2012 (full reference at end of blog), 12% of incoming plant shipments in 2009 were infested by a quarantine pest. This is an approach rate that is 100 times greater than the 0.1% rate documented for wood packaging (Haack et al. 2014). I have discussed the living plant introductory pathway and efforts up to 2014 to get it under control in my report, Fading Forests III.
Shortcomings of the Final Q 37 Rule
So – how well does this final rule meet APHIS’ objectives?
First, will it shift much of the burden of preventing new pest introductions from the importer and APHIS to the exporter, while ensuring the system’s efficacy? In my view, on behalf of CISP, it falls short.
The new rule sets up a process under which APHIS might require that some types of imported plants be produced and shipped under specified conditions intended to reduce pest risk. However, non-American entities have little incentive to protect America’s natural and agricultural resources and from invasive species. So any new process needs severe penalties for violators.
We have seen how widespread and persistent compliance failures are for wood packaging under ISPM#15. http://nivemnic.us/wood-packaging-again-11-years-after-ispm15-problems-persist/ For this reason, I (on behalf of the Conservancy) had suggested that APHIS formally adopt a specific goal of “no new introductions”. I recognized that this goal was unachievable per se, but suggested that it should stand as a challenge and be the basis for adopting stringent restrictions on plant imports. I suggested limiting plant imports to those either a) produced under integrated pest management measures systems (verified by third-party certification) or b) plants brought into facilities operating under post-entry quarantine conditions — and following other best management practices that had been developed and supervised by independent, scientifically-based bodies.
In my current view, APHIS’ regulation falls far short of either this goal of shifting burdens or setting a truly stringent requirement. In fact, APHIS has explicitly backed away from its own original goals and procedures.
The new regulation does authorize APHIS to choose to set up import programs under which the exporting country agrees to produce plants for the U.S. market under a system of integrated pest risk management measures (IPRMM) approved by APHIS. In accordance with the international standards, the programs established under this new power will address how the place of production will manage pest risk and ensure traceability of plants; how APHIS and the exporting country will administer the program; how plant brokers will ensure plants remain pest-free while in their custody; how audits will be performed to ensure program efficacy; and what actions various parties will take in cases of noncompliance.
How efficacious this new approach will be in preventing new introductions will depend on how aggressive APHIS is in both choosing the plant taxa and places of-origin to be managed under such IPRMM programs and in negotiating the specific terms of the program with the exporting country.
It is discouraging that APHIS has ratcheted down how frequently it expects to rely on the IPRMM approach. In the explanatory material accompanying the final regulation, APHIS clarifies that did not intend that IPRMM would be used for all imports of living plants. The IPRMM framework is described as only one of several means to achieve the goal of preventing introduction of quarantine pests. APHIS will choose the “least restrictive measures” needed to prevent introduction of quarantine pests. To clarify its position, APHIS changed the introductory text to indicate that IPRMM will be applied when such measures are necessary to mitigate risk – that is, “when the pest risk associated with the importation of a type of plants for planting can only be addressed through use of integrated measures.” [Emphases added]
The final rule is also discouraging in some of its specifics.
Whereas the draft regulation specified steps that places of production must take to ensure traceability of the plants they produce, in the final regulation the traceability elements specified in each IPRMM agreement will depend on the nature of the quarantine pests to be managed. Again, APHIS seeks to ensure that its requirements are not unnecessarily restrictive.
Although the international standard had specified severe penalties when a grower or broker violated the terms of the IPRMM agreement, APHIS proposed to base the regulatory responses to program failures on existing bilateral agreements with the exporting country. Despite the Conservancy’s plea that APHIS follow ISPM#36 in adopting more specific and severe penalties, APHIS has not done so. The one bright spot is that APHIS may verify the efficacy of any remedial measures imposed by the phytosanitary agency of the exporting country to correct problems at the non-compliant place of production. [Emphasis added]
APHIS is relaxing the detailed requirements for state post-entry quarantine agreements – despite the Conservancy’s concern that such agreements’ provisions could be influenced by political pressure and other nonscientific factors.
Two Improvements
I am pleased that APHIS has retained requirements applied to plant brokers, despite one commenter’s objections. Brokers handling international shipments of plants grown under an IPRMM program must both handle the plants themselves in ways that prevent infestation during shipment and maintain the integrity of documentation certifying the origin of the plants. A weakness, in my current view, is that APHIS will allow brokers to mix consignments of plants from more than one producer operating under the IPRMM program. APHIS does warn that if non-compliant (infested) plants are detected at import, all the producers whose plants were in the shipment would be subject to destruction, treatment, or re-export.
A major improvement under the new regulation is that APHIS will now operate under streamlined procedures when it wishes to amend the requirements for importing particular plants (whether a taxon, a “type”, or a country of origin). Until now, APHIS has been able to make such changes only through the cumbersome rulemaking process, Instead, APHIS will now issue a public notice, accept public comments, and then specify the new requirements through amendment of the “Plants for Planting Manual” [ https://www.aphis.usda.gov/import_export/plants/Manuals/ports/downloads/plants_for_planting.pdf ] APHIS estimates that such changes can be finalized four months faster under the new procedure.
A Final Caveat
Finally, APHIS needs to be able to measure what effect the new procedures have on preventing pest introductions. Such measurement depends on a statistically sound monitoring scheme. APHIS has stated in some documents that the current Agriculture Quarantine Inspection Monitoring (AQIM) system doesn’t serve this purpose. APHIS needs to develop a valid monitoring program.
References
Haack RA, Britton KO, Brockerhoff EG, Cavey JF, Garrett LJ, et al. (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
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. www.frontiersinecology.org
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.
In July 2016 I blogged about the risk that native plant nurseries in California might spread various Phytophthoras to natural areas through use of infected plants used in restoration plantings.
In response to this threat, the California Oak Mortality Task Force has formed a Phytophthoras in Native Habitats Work Group to protect wildlands and assist the restoration industry in adopting practices to ensure they are producing “clean” plants.
The California Native Plant society (CNPS) adopted a policy to promote propagation practices that help prevent plant diseases. CNPS also established its own Ad Hoc Committee on Phytophthoras to address the same threat.
Numerous resources, including guidelines for nursery management, restoration plantings, summaries of committee meetings, photographs, etc., are posted at this website.
As I described in the July 2016 blog, Phytophthora pathogens have been detected in nurseries in other states, including Maryland, Minnesota, North Carolina, Oregon, and Tennessee. Doubtless nurseries in additional states also harbor damaging pathogens.
I’m not aware of action by regulatory officials, nursery owners, or conservation practitioners in these other states to evaluate and address this threat? Are you?
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.
CBP inspecting wood packaging; CBP photo
shipment of decorative stone with wood packaging
laurel-wilt killed swamp bay in the Everglades
dogwood anthracnose