phytodoer@aol.com

Help promote new film about tree-killing pests!

A new film demonstrating the impact of non-native tree-killing insects and diseases will be shown on or around Arbor Day (April 20). You can help ensure that lots of people see the film!!! Contact the program manager at your local PBS channel to ask that the channel broadcast the film.

ash tree killed by EAB; Ann Arbor, MI; courtesy of Major Hefje

“Trees in Trouble: Saving America’s Urban Forests” focuses on emerald ash borer in Cincinnati. The film explores our connections to the trees and forests in our communities – and the threats to those trees. The film’s website links viewers to resources for taking action.

To see clips from the film and other resources go to this site.

The film was produced by Torrice Media. Featured experts and speakers include Prof. Dan Herms of Ohio State, Jenny Gulcik, a community forestry consultant, and Cincinnati Council member Wendell Young.
As we all know, killer pests threaten trees across the country, not just in southern Ohio! Such pests are usually introduced first in cities – not necessarily ports! – because that is where crates and pallets, imported ornamental plants, and other articles to which pests attach arrive. Furthermore, trees along streets and in yards and parks are often more vulnerable than forest trees to such introduced pests because they are often subject to other stresses such as soil compaction, air pollution, elevated temperatures, and salt exposure. Finally, city trees are often planted as multiple individuals of the same species; when a pest that attacks that species arrives, entire neighborhoods can lose their tree canopy – and the real values that canopy provides.
Because of the high value of urban trees, these pests’ greatest economic damage is in urban and suburban areas. The study by Julianne Aukema and others documented that municipalities spend more than $2 billion annually to remove trees killed by non-native pests. Homeowners spend $1 billion a year removing trees killed by non-native pests, and another $1.5 billion is lost in property values due to tree mortality.

Thus, it is vitally important that American city dwellers learn about the values that trees provide to them, the threat to those values from introduced pests, and what they can do to minimize this threat. “Trees in Trouble” is a tool to advance citizens’ understanding of these issues through a combination of broadcasts, compelling video presentations and active civic engagement efforts linked to the film.

goldspotted oak borer

Some people – less familiar with the issue than we are – do not immediately understand the relevance of Cincinnati’s story to other cities. We know that while the trees and killers differ across the country, the cost to the communities is the same: destruction of trees that provide shade and other important ecosystem services and create our sense of home. Plus, the ways these pests are introduced are the same – and so are the steps we can take to reduce this threat.

[The goldspotted oak borer illustrates the universality of this threat – trees in southern California are being killed, too!]
You can help overcome this roadblock!
If you would like to help promote the film to your local PBS station or to local viewers, contact Andrea Torrice at 513-751-7050 or here

If you would like to obtain a copy of the film to screen to your group, contact Andrea Torrice at the same phone number or website. (Andrea is Italian; her name is pronounced “to re chay”, with the accent on “re”.)
Source:
Aukema, J. E., B. Leung, K. Kovacs, C. Chivers, K. O. Britton, J. Englin, S. J. Frankel, R. G. Haight, T. P. Holmes, A. M. Liebhold, D. G. McCullough, and B. Von Holle. 2011. Economic Impacts of Non-Native Forest Insects in the Continental United States. Plos One 6.

Posted by Faith Campbell

Invasive plants in the West

Much of the attention to invasive plants has focused on herbaceous plants (forbs and grasses) invading grasslands and sagebrush steppes of the West. Certainly these plants have invaded large areas and have – in the case of “strong” invaders – caused significant changes not just in plant community composition but also to food webs and even ecosystem structure and function. Some of these invaders have imposed large costs by reducing livestock forage, fueling more frequent fires, or contributing to severe declines in populations of iconic wildlife species.
For these reasons, the House Interior and Oversight committees have held several hearings on invasive species in recent years. Much of the committees’ focus has been on invasive plants and the failure of federal land-managing agencies to curtail or reverse their spread.

Scotch broom; photo by Eric Cooms, Oregon Department of Agriculture

At the most recent hearing, Dr. George Beck of Colorado State University noted that the number of acres of land managed by the Bureau of Land Management that has been invaded by harmful non-native plants has doubled since 2009, reaching 77 million acres. Dr. Beck and his allies in the Healthy Habitats Coalition (HHC) believe that federal agencies could bring about a decline in the “weed”-infested area if they focused their resources. The HHC has persuaded members of Congress and Senators to introduce two bills (H.R 1485 & S. 2240) which would, inter alia, require land-managing agencies to allocate their invasive species funds according to the following formula: 75% for on-the-ground activity; 15% for combined research and outreach; 10% or less for administrative costs. (I discussed these proposals in my blog of January 4th.) The HHC apparently has given up trying to persuade the Congress to increase funding for land managing agencies’ resource management programs; instead, they seek to re-direct existing (shrinking) agency funds away from environmental compliance, planning, priority-setting, and research and to “on-the-ground” actions.

But I don’t think reversing plant invasions should be tackled without science and planning.

The remainder of this blog is based on the research results of Dean Pearson, USFS researcher based in Montana. See particularly the three sources listed at the end of the blog.

Studies have shown that simply suppressing the target weed does not ensure mitigation of its impacts. Managers need to weigh the success of control measures against their side effects. In the end, it is often very difficult if not impossible to restore invaded ecosystems to their pre-invasion condition. Instead, the goal of “weed” management should be to improve the system as a whole, as measured by the overall system response to management and not simply by the degree to which the target weed is suppressed. Pearson calls this “directed community assembly”.
Acting otherwise – wasting limited funds and resources on programs that don’t succeed; or – worse – that result in exacerbated ecological damage – is not acceptable! Nor is it acceptable – in my view – to be so focused on providing forage for livestock as to ignore invader- or management- induced decimation of native forbs (see below).

Pearson’s studies have focused on efforts to suppress spotted knapweed, one of the worst invaders in the grasslands of the intermountain West. Spotted knapweed invasions have both direct and indirect effects on these systems, including replacing the principal native forb (arrowleaf balsamroot); causing significant declines in invertebrates such as grasshoppers that are fed on by many small predators such as birds, small mammals, and spiders; and probably decreasing forage for domestic and wild ungulates. Invasive European forbs (including spotted knapweed) are generally larger, more rigid, and more structurally complex than the native grassland vegetation. This shift in vegetation architecture has led to a dramatic increase in native web-building spiders, resulting in an astonishing 89-fold increase in predation rates on spider prey. Knapweed invasions also apparently increase soil erosion and change the availability of soil nutrients. So, knapweed invasions have significant and persistent ecological effects. The variety of effects means that controlling spotted knapweed is likely to restore pre-invasion conditions only to the extent that native vegetation recovers. Recovery of the plant community might in turn depend on the ability to mitigate abiotic impacts of invasion, restore seed sources, and address similar factors that may interfere with native plant recovery.
Addressing the complexity of natural systems’ responses to plant invasion is difficult, especially given the limitations of available management tools.

According to USFS researchers Dean Pearson and Yvette Ortega, to improve weed management in natural systems, we need to better understand three important factors that greatly complicate natural areas weed management. Managers need to:
1) determine the invasive plants’ impacts on species, community, and systems; and which ones may be amenable to mitigation given current tools.
2) understand how prospective management tools might cause deleterious side effects and what can be done to minimize those effects.
3) understand the ecological conditions and processes underlying secondary weed invasions so that they can develop strategies to reduce the risk of secondary invasion following target invader suppression. (Pearson & Ortega 2009)

Programs aimed at countering plant invasions – no matter the method used – can cause unwanted damage to the ecosystem (= side effects). Side effects might affect not just non-target native plants, but also higher trophic levels, community interactions, and even ecological processes structuring the system.
These side effects need to be balanced against the damage caused by the invasive plants due to the complexity of natural systems and the limited specificity of the tools employed. Some might persist for years after control of the invasive plant. Managers need to consider the effects of both the invasive plants and the management action when selecting a strategy.

Forbs commonly making up ~80% of species richness in the intermountain meadows. In some un-invaded plots in western Montana, arrowleaf balsamroot mean cover was twice that of the native grass bluebunch wheatgrass. Forbs support communities of pollinators, herbivores, and higher trophic levels. Both invasion by alien forbs such as spotted knapweed and weed control efforts using either herbicides or grazing can lead to suppression of the native forbs. Thus at the study sites, broadcast spraying of the herbicide picloram reduced arrowleaf balsamroot cover and fecundity variables by nearly 60%. In this case, knapweed control efforts actually exaggerated the trajectory of species composition change initiated by spotted knapweed invasion – even when the invader was successfully removed.
Biological control is the most selective weed management tool currently in use other than hand pulling. However, even highly host-specific biocontrol agents can have rather significant non-target effects. One example is the dramatic increase in deer mouse populations in areas where they can feed on gallflies introduced as biocontrols for knapweed. Deer mice support the hantavirus pathogen, so this represents a potential human health threat. Worst of all, the gallflies have not proved effective at reducing knapweed populations – so the invasive plant, the mice, and the virus now all thrive. (In cases when the biocontrol agent is efficacious in significantly reducing the target plant species, any undesirable side effects will also be reduced.)
Furthermore, success in suppressing invasion by one set of plants often facilitates invasion by some other plant species that might cause greater changes to the system or that are harder to control. The problem of secondary invaders is not limited to any one management strategy, target weed, or secondary invader. Pearson think secondary invasion is likely any time additional species of strong invaders are present at a site where a dominant weed is controlled and the secondary invader proves relatively insensitive to the control method.

Grasses are most often the secondary invaders (whereas most target weeds were forbs). Perhaps, at least in some cases, weed control is simply accelerating general patterns of invader succession. In their study area in western Montana, Pearson and Ortega have found that cheatgrass invasion occurred faster in herbicide treated areas, but it also occurred in both otherwise un-invaded native grasslands and untreated spotted knapweed-invaded sites.
Secondary invasion by cheatgrass might be a particularly common consequence of weed control measures in western North America, given the species’ widespread occurrence, and its ability to exploit resources released by suppression of perennial taxa, outcompete native grasses, and attain dominance even when present at low initial densities (Ortega and Pearson 2010).

Pearson calls for understanding and addressing the system-level processes such as propagule pressure or disturbance underlying and promoting invasions in order to minimize secondary invasions.

In some cases, full restoration is not the manager’s goal. Managers of areas managed primarily as grazing lands might accept loss of forbs; even cheatgrass can be used as forage during part of the year. However, large scale reductions of forb diversity in grassland systems would not be acceptable in natural areas management.

While I think highly of Dr. Pearson’s studies, I think that researchers in the West pay too little attention to the contributing role of propagule availability, especially people’s role in taking propagules to sites where they can initiate invasions. Human movement of plants to satisfy wants for ornamental horticulture, or as unwise choices for erosion control or wildlife forage and shelter plants explains numerous examples of invasive forbs, shrubs, and trees proliferating across the West. However, there are also recent examples of unwise propagation of livestock forage grasses – cold-tolerant buffelgrass, anyone?
——————————–
Sources of scientific evaluations of plant management strengths and difficulties:

Yvette K. Ortega and Dean E. Pearson. 2010. Effects of Picloram Application on Community Dominants Vary With Initial Levels of Spotted Knapweed (Centaurea stoebe) Invasion. Invasive Plant Science and Management 2010 3:70–80

Pearson, D. E. and Y. K. Ortega. 2009. Managing invasive plants in natural areas: moving beyond weed control, pp 1-21, in (ed.) R.V. Kingley, Weeds: Management, Economic Impacts and Biology. Nova Publishers, NY

Ortega, Y. K., and D. E. Pearson. 2005. Strong versus weak invaders of natural plant communities: assessing invasibility and impact. Ecological Applications 15:651-661.

Posted by Faith Campbell

Invasive plants – huge numbers, continuing introductions & spread …

The U.S. is badly invaded by non-native plants. In the database he maintains,
Rod Randall of Western Australia reports that more than 9,700 non-native plant species are naturalized in the U.S. In this compendium, Randall defines “naturalized” species as those having self-sustaining and spreading populations with no human assistance. Not all of these species impact upon the environment.

As noted, not all 9,700 species are “invasive”. It is likely that a significant proportion of the invaders are “weak” invaders which coexist with the native plants and make up minor components of the plant community. Others are “strong” invaders that can rapidly attain community dominance and dramatically impact native species and ecological processes (Ortega and Pearson 2005).

But the evidence is that the situation will grow worse. A study of a small proportion of the naturalized plants (1201 alien species; 755 invasive; Bradley, Early & Sorte 2015) found that
– Invasive and alien plants are more widely distributed than natives across the continental United States
– The average invasive plant now inhabits only ~ 50% of its expected range
– Biological factors are less important than human actions in facilitating spread

According to Dr. George Beck of Colorado State University, by 2015, the acreage of land managed by the BLM that is invaded by non-native plants exceeds 77 million acres – more than twice the areas reported in 2009 (35 million acres) (see Dr. Beck’s testimony here). I noted in my blog about threats to U.S. National parks that are World Heritage sites (October 21, 2015), National parks from Hawai`i to Florida have been badly damaged by invasive plants.

Another source reports that more than 500 plant species invasive in some region are being sold on-line globally (Humair et al. 2015).

USDA APHIS has adopted a pre-import risk-screening system. Based on these analyses, utilizing the NAPPRA process, in April 2013 APHIS determined that 41 plant species may not be imported until a risk assessment has been conducted because of the risk they pose of being invasive. APHIS proposed a second group of species, containing 22 species, in May 2013. However, this list has not been finalized two and a half years later – despite meeting with conservation organizations/stakeholders in April 2015 at which we discussed ways to speed up the approval process. (We were told that the delay is caused by controversy over taxa proposed for NAPPRA-listing because their link to plant pests; that there is no controversy over the taxa to be restricted as potentially invasive plants.)

Clearly the threat from invasive plants is great and growing. The U.S. Department of Agriculture needs to adopt procedures that enable APHIS to act more quickly to curtail introduction and human-assisted spread of invasive plants. APHIS and federal land-managing agencies need adequate resources to develop and apply effective and environmentally sound control measures.

Sources
Bradley, B.A., R. Early & C. J. B. Sorte. 2015. Space to invade? Comparative range infilling and potential range of invasive and native plants. Global Ecology and Biogeography

Humair, F., Humair, L., Kuhn, F. and Kueffer, C. (2015), E-commerce trade in invasive plants. Conservation Biology, 29: 1658–1665. doi: 10.1111/cobi.12579
Ortega, Y. K. and D. E. Pearson. 2005. Strong versus weak invaders of natural plant communities: assessing invasibility and impact. Ecol. Appl. 15:651–661

posted by Faith Campbell

Fed up by lack of action on invasive species? Let’s pressure the right targets!

On December 1, the House Oversight Committee, Subcommittee on Interior, held a hearing on invasive species. This hearing was apparently held at the request of the ranking Democrat, Brenda Lawrence of Michigan. Ms Lawrence is most concerned about aquatic invaders in the Great Lakes. Chairwoman Cynthia Lummis is from Wyoming, so her focus is on invasive plants on western rangelands.
Chair Lummis opened the hearing, but left promptly. Other subcommittee members who were present for varying lengths of time were Paul Gosar (R-AZ), Ken Buck (R-CO), Gary Palmer (R-AL), Brenda Lawrence (D-MI), and Stacey Plasket (D-USVI) ; from full committee: Will Hurd (R-TX).

The witnesses were the newly appointed executive director of the National Invasive Species Council (NISC), Jamie Reaser; the president of the Reduce Risk from Invasive Species Coalition (RRISC), Scott Cameron; Dr. George Beck of Colorado State University, representing the Healthy Habitats Coalition (HHC); and Dr. Alan Steinman, expert on aquatic invaders from Grand Valley State University in Michigan.
This hearing followed those in past years that had been stimulated by the HHC. Both HHC and Congressional members expressed great frustration that the federal government is not putting sufficient effort into stopping or reversing the spread of invasive plants on western rangelands.
The December hearing – like its predecessors – focused the criticism on NISC. I think this focus is misguided. NISC has no independent authority or power; it was created to coordinate agencies’ actions, not to substitute for them. Its staff lack sufficient rank to tell agencies what to do.
In § 4 of Executive Order 13112, NISC’s duties are listed as providing national leadership through (a) overseeing implementation of this order, seeing that Federal agencies’ activities are coordinated, complementary, cost-efficient, and effective, …; (b) encouraging planning and action at local, tribal, State, regional, and ecosystem-based levels …; (c) developing recommendations for international cooperation …; (d) developing, in consultation with the Council on Environmental Quality, guidance to Federal agencies pursuant to the National Environmental Policy Act (NEPA)…; (e) facilitating development of a coordinated network among Federal agencies to document, evaluate, and monitor IAS impacts …; (f) facilitating establishment of an … information-sharing system …; and (g) preparing a national Invasive Species Management Plan every two years.
NISC has fallen far short of these requirements. It has not succeeded in developing guidance on NEPA – at least in part because CEQ has not cooperated. Most glaringly, NISC has issued only two Management Plans over 15 years — the most recent in 2009. All Members at the hearing complained to Reaser about this failure. Members see the Plan as key to setting priorities and ensuring that funds are well-spent.

All Members seemed to think that NISC actually should carry out on-the-ground activities and direct agencies’ priorities. Some want NISC to overcome federal agencies’ alleged foot-dragging in helping local groups eager to attack local problems, or to pressure Native American tribes to cooperate.

While I share the critics’ frustration about federal agencies’ inaction, I believe the productive approach is to apply pressure on – and where deserved, support for – those who have the authority and power to act, but who often choose not to. These are:
• heads of agencies and departments, especially the secretaries of Agriculture and Interior and their Under and Assistant secretaries;
• the President;
• budget staffs of these and other relevant agencies;
• the Office of Management and Budget;
• Members of the Congressional appropriations committees.

If these people think that dealing with invasive species is politically important, they will do so. If they don’t hear from their constituents about invasive species, they will focus on other issues.

At the hearing, Scott Cameron, of RRISC, said that what is missing is commitment at the Assistant/Under Secretary Level. Such a commitment would both drive coordination among agencies at headquarters and provide “cover” for regional staff trying to work together. He feels that a new Management Plan is useful but not sufficient. Scott made several recommendations intended to raise the political visibility of invasive species issues:
1) NISC submit annual work plan to Congress – he thought this would get political level attention in the departments;
2) NISC serve as forum to coordinate with regional governors’ associations;
3) NISC create national network of regional early detection/rapid response efforts;
4) NISC serve as forum for regional officials of land-managing agencies to coordinate and work together – this might succeed in getting attention of agency leadership and OMB;
5) NISC ensure coordination of priorities and approaches by member agencies at headquarters level; and
6) NISC evaluate best practices by other governments, propose their adoption by the United States.

Dr. Beck, of HHC, reiterated his constituency’s complaint that there has been little progress on invasive species problems despite three decades of effort. He blamed the lack of leadership by NISC – without saying how staff can “lead” the political appointees who head agencies! He called – again – for abolition of NISC and transfer of its $1 million budget to “on the ground” programs. Beck also decried inconsistencies in agencies’ budgets, lack of collaboration with states and local groups in setting priorities, and NEPA having become an excuse to avoid taking action.

HHC has promoted introduction of bills in both the House and Senate – H.R 1485 & S. 2240 – which would require:
• strategic planning;
• cooperation with states;
• categorical exclusion from NEPA review for efforts to protect high-priority sites;
• 5% annual reduction in weed species’ extent; and
• allocation of agencies’ invasive species funds according to the following formula: 75% for on-the-ground activity; 15% for combined research and outreach; 10% or less for administrative costs.

Of these recommendations, I think the proposed dropping of environment reviews of invasive species management programs – especially in “high priority” sites of high ecosystem values – would be a disaster. Management programs have environmental impacts, too; and some approaches cause more harm than good. For example, use of herbicides to eliminate knapweeds has sometimes resulted in takeover of the site by non-native annual grasses that are even more difficult to control.

Also, I think the proposed funding allocation is very unwise. Research and outreach often contribute enormously to control or containment of invasive species. I have been unable to get straight answers from the USDA Forest Service about how such an allocation would affect their programs – which are divided among three separate entities – Research, State and Private Forestry, and National Forest System.

HHC is very active in promoting its position – and those of us who think differently are not yet being heard in Congress.

I think there is room to work with members of the House Oversight Committee to focus more attention on the agencies’ political leadership – where it belongs and where pressure might have an effect. Rep. Lawrence seems interested in continuing efforts. Rep. Hurd of Texas asked about steps to prevent plant pest introductions (none of the witnesses knew about APHIS programs). Furthermore, a second Michigander, Rep. Dan Benisheck, and a Californian, Rep. Mike Thompson, co-chair the Invasive Species Caucus. Although none of them has yet expressed concern about tree-killing pests, given where they are from they might be persuaded to engage.

At present, the only Congressional champion for effective invasive species programs – especially as regards tree-killing pests – is Senator Leahy of Vermont. He has helped prevent further cuts in budgets for APHIS and USFS. We need more friends in Congress.

I urge you – and your friends! – to contact your Representatives and Senators to explain how invasive species are damaging important ecological and economic resources in your state. Ask them to work with their colleagues to support and improve federal programs aimed at preventing new introductions, containing species already introduced, and developing effective methods to reduce pests’ impacts and restore native forests.

Posted by Faith Campbell

Firewood – some states & federal agencies still have not acted to contain the threat

Examples abound of pest spread by this means:
• Emerald ash borer: outbreaks near campgrounds in West Virginia, Missouri, New Hampshire, and many other states.
• Goldspotted oak borer: initial outbreak at campgrounds in Cleveland National Forest in San Diego County. Subsequently, outbreaks distant from the original site have been detected in Idyllwild in Riverside County, Weir Canyon in Orange County, and in Green Valley in Los Angeles County.
• Redbay ambrosia beetle and associated laurel wilt disease: outbreaks in Everglades National Park and in Texas.
It is widely believed that many other geographically distant outbreaks of damaging pests have been caused by movement of firewood.
About half the states have adopted regulations governing movement of firewood in order to reduce the risk that moving firewood can spread non-native, tree-killing insects far from existing outbreaks to new, vulnerable forests. Among states at greatest risk are states of the central South – Texas, Arkansas, Missouri; and California. All these states are at high risk due to numbers of campers visiting sites on their territories & growing presence of wood-boring pests.

A study by USDA Forest Service researcher Frank Koch and others found that the highest level of camper travel in the U.S. was to lakes and reservoirs in National forests in an area reaching from eastern Texas to Missouri. Arkansas and Missouri regulate hardwood firewood entering the state because of risk of transporting thousand cankers disease of walnut. Both also have internal state quarantines for emerald ash borer; movement of hardwood firewood from within those quarantine zones is prohibited. Firewood from the southern portion of Arkansas is also subject to quarantines intended to prevent movement of the red imported fire ant.
Texas also regulates firewood stored outside in red imported fire ant quarantine; this quarantine applies to all of the forested areas of the state, so presumably movement of firewood within this large area is allowed. The absence of regulations does not address the threat from one firewood-associated pest – the soapberry borer – already widespread in Texas; nor the increasing risk from EAB, which is established in several neighboring states (see link above). Texas ash is an important component of forest in hill country. Texas ash is a key food for prey fed to nestlings of the endangered golden-cheeked warbler.
If Texas becomes a bridge by which EAB reaches Mexico, another dozen species of ash will be at risk.
California also does not regulate movement of firewood either generally or by visitors to state parks (see my blog of September 27). California does regulate movement of firewood into the state. And the California Department of Food and Agriculture and CalFire do invest significant resources in outreach and education efforts asking Californians not to move firewood.
In October, Dr. David Wood, emeritus professor of forest insects at UC Berkeley, and I submitted a petition to the California Department of Food and Agriculture asking that it regulate movement of firewood in the state. We cited specifically the recent detection of a new outbreak of the goldspotted oak borer at Green Valley in Los Angeles County.

goldspotted oak borer

In our petition, we acknowledged that CDFA has been active in outreach programs urging Californians not to move firewood. We said that we feared that the educational effort could not succeed in the absence of regulations. First, the lack of regulation allows firewood vendors to ignore the educational message, since there is no sanction. At a deeper level, failure to regulate also conveys an impression that the risk associated with firewood is not considered sufficiently serious to warrant an official response.
In November, CDFA denied our petition. The agency cited the fact that the GSOB detection did not occur until perhaps 20 years after its initial introduction; the absence of pests in firewood from Arizona and Mexico inspected at California border stations; the failure of the federal quarantines targeting EAB to slow that insect’s spread; the insect’s own flight capacity; and – especially – the large number of people moving firewood and other possible vectors of the insect around the state. CDFA re-iterated its belief that the most effective response combines research to develop better detection and management tools public outreach and education.
Of course, numerous other pests are transported in firewood, not just GSOB. These include Polyphagous and Kushiro shot hole borers, pitch canker of pines, sudden oak death, as well as such native insects as the mountain pine beetle.

All these states urge campers to obtain firewood near where they will burn it.
However, I think all are ignoring the lesson from Wisconsin – regulations restricting movement of firewood back up education by providing “teachable moments” and penalizing those who willfully disregard the warnings. To learn about Wisconsin’s successful application of a combination of regulations and outreach, watch the webinar presented by Andrea Diss-Torrance at http://dontmovefirewood.org/blog/webinar-changing-movement-firewood-campers-october-21st.html
Federal agencies also are not doing all they should – as I noted in my blog of August 10. USDA APHIS has enacted quarantines targeting particular species, such as the Asian longhorned beetle and emerald ash borer. APHIS also helps to fund significant outreach efforts, both through the Don’t Move Firewood website and associated programs and working with NASCAR and other sponsors of big events attended by lots of campers. However, APHIS’ plan to control movement of pests in firewood sold in bulk by large suppliers to large retail outlets by developing an industry certification program has been in the works for 5 years and is still not operational.
Some National parks have adopted firewood regulations, but neither the National Park Service nor the USDA Forest Service has adopted nation-wide regulations (see my blog of August 10 and Leigh Greenwood’s blog at http://www.dontmovefirewood.org/blog/nine-national-park-firewood-policies.htm). In the states discussed here, The Ozark National Scenic River (operated by the National Park Service) requires campers to obtain wood within 50 miles of the Park, or to collected dead and down wood at the site. Big Bend National Park has forests in the Chisos Mountains and along the Rio Grande, but it does not restrict visitors’ sources of firewood. Guadalupe Mountains National Park on the Texas border with New Mexico is home to a mixed forest. No fires are allowed in the Park’s two primitive campgrounds. Big Thicket National Preserve allows only hike- or boat-in backcountry camping; I saw no restrictions on firewood.
As I said in August and in an earlier blog of July 15, Yosemite National Park is at great risk to oak-killing insects such as GSOB that could be brought from the ever-larger areas of GSOB infestation in the San Diego and Los Angeles areas. Polyphagous and Kushiro polyphagous shot hole borers might also pose a threat. Yet neither Yosemite nor other National parks in the state have adopted regulations – and their messages urging visitors not to bring firewood are buried in the reservation process.

These states’ failure to adopt firewood regulations contrasts with their willingness to require boaters to clean their boats and trailers to prevent spread of zebra and quagga mussels. Why the different approaches? Do the aquatic organisms have a more compelling story? Are the agencies responsible for aquatic resources more aggressive than agricultural agencies? The threat from mussels was apparent earlier – have states just lost the willingness to act in more recent years? Can we understand the factors and use that knowledge to reverse this discrepancy?
The Continental Dialogue on Non-Native Insects and Diseases pays considerable attention to firewood. See the presentations given at its meeting in mid-November at http://continentalforestdialogue.org/continental-dialogue-meeting-november-2015/
Posted by Faith Campbell

Trans-Pacific Trade Partnership – implications for pests in forests

The aim of the TPP is to further expand trade between the U.S. & Canada and other nations bordering the Pacific. (This does not include China, which is not a party to the pact). At same time, completion of a program to widen the Panama Canal means more huge container ships will travel directly to the East coast from Pacific countries. Clearly, rising trade with distant countries – especially those with similar plant genera – raises the risk of pest introductions. Stress federal and state agencies that are already struggling to counter this threat.

The question is whether the TPP agreement itself will exacerbate this threat. Is there language in the agreement that will further hamper adoption and deployment of effective phytosanitary programs?

Fortunately, I think largely not.

The TPP’s section on sanitary and phytosanitary programs – Chapter 7 largely reiterates or clarifies procedures already included in the WTO SPS Agreement and International Plant Protection Convention. TPP provides additional clarity on some points, e.g., transparency & communication.
(Unfortunately, I believe that the SPS Agreement and IPPC already hamper efforts to protect our trees from alien pests – especially those that are not yet known – the infamous “unknown unknowns”. For my analysis see Fading Forests II, available here. A more optimistic analysis of the SPS Agreement as an obstacle to preventing pest introductions is provided by Burgiel et al. 2006, available here.

I am quite pleased to see that the TPP explicitly allows importing countries to consider their level of confidence in the exporting country’s phytosanitary capability when deciding what measures to impose – a very important improvement! This occurs twice:
• Article 7.8: Equivalence

5. In determining the equivalence of a sanitary or phytosanitary measure, an importing Party shall take into account available knowledge, information and relevant experience, as well as the regulatory competence of the exporting Party. [emphasis added]

• Article 7.10: Audits

6. A decision or action taken by the auditing Party as a result of the audit shall be supported by objective evidence and data that can be verified, taking into account the auditing Party’s knowledge of, relevant experience with, and confidence in, the audited Party. This objective evidence and data shall be provided to the audited Party on request. [emphasis added]

I am also pleased that the TPP acknowledges the need to act proactively in the face of a threat. Under Article 7.1, Definitions, the definition of “emergency measure” reads:

“ … a sanitary or phytosanitary measure that is applied by an importing Party to another Party to address an urgent problem of human, animal or plant life or health protection that arises or threatens to arise in the Party applying the measure;” [emphasis added]

The TPP also puts protecting human, animal, or plant life or health first – before facilitating trade – when specifying the agreement’s objectives. See Article 7.2: Objectives, paragraph (a), which reads:
(a) protect human, animal or plant life or health in the territories of the Parties while facilitating and expanding trade by utilising a variety of means to address and seek to resolve sanitary and phytosanitary issues;

The TPP reiterates parties’ rights under the World Trade Organization’s SPS Agreement and IPPC to adopt more stringent regulations as long as they justify such action by both adopting a higher level of protection and conducting a risk assessment appropriate to the circumstances. See especially Article 7.9, paragraph 2:
2. Each Party shall ensure that its sanitary and phytosanitary measures either conform to the relevant international standards, guidelines or recommendations or, if its sanitary and phytosanitary measures do not conform to international standards, guidelines or recommendations, that they are based on documented and objective scientific evidence that is rationally related to the measures, while recognising the Parties’ obligations regarding assessment of risk under Article 5 of the SPS Agreement.

I do worry some about Article 7.11, Import Checks, paragraph 8, which states:

8. An importing Party that prohibits or restricts the importation of a good of another Party on the basis of an adverse result of an import check shall provide an opportunity for a review of the decision and consider any relevant info submitted to assist in the review. The review request and info should be submitted to the importing Party within a reasonable period of time.

How does this requirement apply to the U.S. policy of rejecting shipments in wood packaging that does not comply with ISPM#15? (For discussions of the role of wood packaging as a pathway for introduction of highly damaging pests, review my blogs posted on July 15, August 31, September 11, and October 30.) The U.S. does not currently consult with exporting country before denying entry to individual shipments. Nor do we want the U.S. to be required to do so!

Finally, Article 7.17: Cooperative Technical Consultations, paragraph 5 requires countries to involve “relevant trade and regulatory agencies” but says nothing about including other stakeholders, such as cities or homeowners whose trees are at risk to introduced pests.

Posted by Faith Campbell

What is being introduced, and how? APHIS — make data public!

It is important that officials responsible for phytosanitary protection, Congressional oversight committees, and stakeholders have access to key trade and pest data as well as independent analyses of them in order to evaluate programs’ effectiveness.

But we don’t have such access … and existing analyses cannot be used to detect trends.

My focus is on tree-killing insects and diseases, but these constitute a small fraction of the total number of all plant pests that have become established in North America since Jamestown was settled. According to Aukema et al. (2010), approximately 450 non-native insects have colonized forest and urban trees. This is about 17% (less than one-fifth) of the total of 3,540 non-native insects established in North America according to Yamanaka et al. (2015). The larger number includes ones apparently causing negligible harm, along with a significant proportion of insects and diseases affecting row crops.
What could we learn from comparisons of data on introduced tree-related vs. overall plant pests? Could we uncover new pathways? Identify more effective approaches to phytosanitary protection?
Unfortunately, neither published studies nor USDA/APHIS’ data allow comparisons and tracking of trends in pest establishment.

For example, a study by Work et al. (2005) estimated that during the late 1990s, approximately 10 new phytophagous insects were established each year. The authors considered all phytophagous insect pests, not just tree-killing pests; but they did not include pathogens or insects that feed on dead wood (e.g., termites).

The Work team’s number is about four times larger than the estimated rate of establishment provided by Aukema et al. (2010), which estimated that approximately 2.5 new tree-killing insects and pathogens became established each year from 1860 to 2006. The Aukema study did not attempt to track establishments of all pests that use arboreal hosts. On the other hand, it did include pathogens. So the two studies’ findings are not truly comparable.

In its 2009 Implementation Plan for Section 10201 of the Food, Conservation and Energy Act of 2008, APHIS reported that between 2001 and summer 2008, 212 plant pests had been reported as new to the United States – an average of 30 new pest establishments detected each year. This estimate does include pathogens … but not insects that do not feed on living plants. So it is not comparable to the Yamanaka study. Still, the APHIS figure is 12 times higher than the Aukema et al. estimate for tree-killing pests.

I am unaware of a publicly available estimate for more up-to-date establishment rates.

An internal USDA APHIS database was made available to me. It lists about 90 new species of plant pests (of all types, ranging from insects to nematodes to fungal pathogens) with populations that were detected in the U.S. during the four-year period 2009 – 2013. The rate of detection of “new” species established during this four-year period was approximately 22 per year. This establishment rate is higher than the estimate of approximately 10 new phytophagous insects per year during the late 1990s put forward by Work et al. — not surprising since taxa other than insects are included. However, this estimate is lower than the 30 new pest introductions each year estimated by USDA APHIS for 2001-2008.

So what is the current rate? How has the establishment rate been affected by changing volumes of imports over this 20-year period (imports rose until 2008, then fell because of the Great Recession)? How has the reported number of new establishments been affected by changes in monitoring program criteria and funding levels?
Do the databases include sufficient information about dates of probable establishment, likely pathways of introduction, etc., to allow a more complete analysis of at least the new insect species?
I have not seen the database compiled by Yamanaka’s team so I don’t know.

The USDA database from 2009-2013 does not specify the probable pathways by which these pests entered the United States. I have concluded that the viruses, fungi, aphids and scales, whiteflies, and mites were probably introduced via imports of plants, cuttings, or cut foliage or flowers. These pests number 37 – or 41% of the total.

The database on tree-killing insects and pathogens compiled by the Aukema team includes both date of probable introduction and likely pathway; and articles by this team discuss trends in introduction rates. Thus, Liebhold et al. 2012 reports that approximately 69% of the pests in the database were introduced via the trade in live plants. This figure is one-third higher than the proportion I calculated from the USDA database (which, I remind you, includes all plant pests, not only those that attack trees).

Many of the pests associated with imports of plants in the Liebhold study were introduced decades ago, before the U.S. adopted phytosanitary regulations. Does the difference in the proportion of pests associated with plant imports in the 2009-2013 period compared to the earlier period covered by Liebhold et al. reflect a reduced risk from this pathway as the result of tighter regulations and shifts in the market? I doubt anyone can say – beyond the acknowledged increase in wood-borers associated with wood packaging.

Without better, and more readily available, data, we won’t ever be able to answer key questions. It is urgent that APHIS make available its data on trade volumes, pest interceptions, newly established pests, etc., for analysis by academics, other agencies, and stakeholders. And certainly it would be helpful if both APHIS and other researchers used more consistent approaches so to make possible longitudinal studies that can disclose trends.

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

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

Work, T.T.; McCullough, D.G.; Cavey, J.F.; Komsa, R. 2005. Arrival rate of nonindigenous species into the United States through foreign trade. Biological Invasions7: 323-3

Yamanaka, T., N. Morimoto, G.M. Nishida, K. Kiritani, S. Moriya, A.M. Liebhold. 2015. Comparison of insect invasions in NoAm, JP and their Islands Biol Invasions DOI 10.1007/s10530-015-0935-y
Posted by Faith Campbell

Wood packaging again ???!!!!!! Yes – problems need to be fixed!!

CBP inspector views Cerambycid larvae found in wood packaging that bears ISPM#15 stamp

Do we want triple the current number of wood-boring non-native insects to be established in just 35 years? We all know the damage that some of these insects can do (see summary or longer descriptions; for specific insects).
Over the past 30 years, at least 58 non-native species of wood- or bark-boring insects have been detected in the United States (not quite 2 new insects per year). Most were presumably introduced via imported wood, especially wood packaging (Haack et al.).

Yes, the U.S. has implemented the International Standard for Phytosanitary Management (ISPM)#15. Nevertheless, USFS researcher Bob Haack estimates that 13,000 shipping containers per year – or 35 per day – transport tree-killing pests to the U.S. This is the basis for an estimate that by 2050 – just 35 years from now – the number of wood-boring pests introduced to the country will triple above current levels.
We don’t need to rely only on extrapolations to know that APHIS’ implementation of ISPM#15 is not protecting our trees. As noted in my blog of 11 September, inspectors at the ports continue to find insects in wood packaging – even wood packaging marked as having been treated according to the requirements of the standard. Nearly half of the wood packaging entering the country that does not comply with the treatment requirements comes from Mexico. U.S. and Mexican forests are separated by deserts – allowing insects to evolve there to which our trees are vulnerable (see my blog from 11 September and descriptions of goldspotted oak borer, soapberry borer, and walnut twig beetle and its accompanying fungus here).
An on-going study seeks to identify insect larvae found in wood packaging; it is a cooperative effort of USDA APHIS’ laboratory at Otis, Massachusetts, and Customs and Border Protection staff at eight ports. Since 2012, these ports have sent 848 cerambycid and buprestid beetle larvae to Otis for identification. The APHIS scientists have succeeded in identifying 292 larvae, or only 34%. They constituted 39 species and 29 genera.

At least 44 of these insects were from China; they included 6 Asian longhorned beetles. Remember, the U.S. first adopted regulations requiring China to treat its wood packaging at the end of 1998 – nearly 17 years ago!!! Another 20 insects were from Russia – which has been required to treat its wood packaging since early 2006 – nearly 10 years ago.
As noted in the documents linked to above, and in earlier blogs (15 July, 22 and 31 August, 11 September), wood-boring pests collectively have been the most costly of the types of tree-killing pests introduced. One study estimated that they cost local governments and homeowners $2.4 billion each year to manage dying and dead trees. The homeowners lose another $830 million in residential property values.

What the Government Has Done

While USDA APHIS has cracked down on U.S. producers of wood packaging who cheat and is promoting workshops to educate our trade partners on wood packaging treatment requirements, the government should do more to protect our forests.

What More Can be Done

• At present, U.S. policy allows an importer to be caught 5 times in 1 year with wood packaging that does not comply with the regulatory requirements. Requirements adopted a decade or more ago should be enforced more strictly! The Bureau of Customs and Border Protection and USDA APHIS should instead penalize all importers whose wood packaging does not comply with regulatory requirements.

• The Bureau of Customs and Border Protection should incorporate the wood packaging requirements into its “Customs-Trade Partnership Against Terrorism” (C-TPAT) program .

• USDA APHIS should re-examine the economic pros and cons of requiring importers to switch to packaging made from materials other than wooden boards. The new review should incorporate the high economic and ecological costs imposed by insects introduced via the wood packaging pathway.

• USDA leadership should move forward and the President’s Office of Management and Budget should approve final regulations – proposed by APHIS 5 years ago! – that would apply the same treatment requirements to wood packaging used in trade between the US and Canada. (Canada has been ready to adopt this measure for several years.)

Sources (my apologies – I apparently cannot attach to specific points in the blog):

Aukema, J.E., B. Leung, K. Kovacs, C. Chivers, K. O. Britton, J. Englin, S.J. Frankel, R. G. Haight, T. P. Holmes, A. Liebhold, D.G. McCullough, B. Von Holle.. 2011. Economic Impacts of Non-Native Forest Insects in the Continental United States PLoS One September 2011 (Volume 6 Issue 9)

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.009661

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

Posted by Faith Campbell

New IUCN report notes invasive species threat to World Heritage Sites – Including U.S. National Parks

The World Conservation Union (IUCN) has just released a report, IUCN World Heritage Outlook 2014 (for press release, click here; for the full report, click here)
that names invasive species as the second most significant threat World Heritage sites with outstanding natural values. (Poaching is the greatest threat).

World Heritage sites have “outstanding universal values” – either natural or cultural. Natural sites are areas either of exceptional beauty or representative of major stages of Earth’s history, significant ongoing ecological processes, or significant habitats for biodiversity and threatened species.

The 2014 assessment examined 229 natural World Heritage sites and found that 104 are affected by invasive species. Unsurprisingly, island sites are especially heavily impacted. Two-thirds of the affected island sites (24 out of 36) are in the tropics.

The most widespread or common invaders are plants; they are named in 55 of the 104 affected sites. Invasive vertebrate animals affect at least 12 sites. These frequently include fish (mostly trout), cats, and rodents (especially rats).

The report calls for effective management strategies to protect the World Heritage sites. Such strategies include well-defined plans as well as strict bio-security measures, including limiting materials entering the site or the eradication of problem-causing species. Ideally, these actions involve local communities. Among the 104 natural World Heritage areas affected by invasive species, 87 have management projects addressing at least some invasive species or related issues.

According to the report, future invasive species management will be even more challenging, especially because of climate change. Climate change, itself, could become the biggest threat to natural sites in future.

dead sweetbay in Big Cypress National Preserve, Florida

The United States has 21 World Heritage sites. Nine were chosen for their outstanding natural values. These include the following National parks: Everglades, Grand Canyon, Great Smoky Mountains, Hawaii Volcanoes, Redwood, Yellowstone, and Yosemite National parks; and – jointly with Canada – Kluane / Wrangell-St. Elias / Glacier Bay / Tatshenshini-Alsek and Waterton-Glacier National parks.

Several of these natural wonders are well known to be threatened by invasive species – including some tree-killing insects and pathogens.

Everglades National Park. In Everglades, pythons have decimated populations of small to medium native mammals. Lionfish are killing vast numbers of fish in the shallow bay. Numerous invasive plants, especially Australian pine, Melaleuca, Brazilian pepper, and old world climbing ferns transform the natural sawgrass prairie and mangroves. Some, e.g., Melaleuca, are under control thanks to persistent effort over decades.

Laurel wilt has almost eliminated swamp bay trees from the hammocks. Bromeliad weevil has killed many bromeliads in 12 genera (of the 16 present in Florida).

Tillandsia utriculata bromeliad in Florida

Great Smoky Mountains National Park. The outstanding biological diversity of the forested Great Smoky Mountains National Park has been severely undermined by chestnut blight, hemlock woolly adelgid, balsam woolly adelgid; and is now under attack by more recent invaders, including beech bark disease, emerald ash borer, and thousand cankers disease of walnut. Descriptions of all these pests are available here. At ground level, feral hogs damage plants, soil-dwelling invertebrates and small vertebrates, even birds. Rainbow trout compete with native trout in the streams. More than 380 non-native plants compete with the native species. The Park’s website features another invader, the Asian jumping worm (Amynthas agrestis), which has been introduced through bait.

The Great Smoky Mountains are the center of biological diversity for salamanders which are likely soon to face danger from the “Bsal” pathogen – unless the Fish and Wildlife Service acts to restrict imports of salamanders by the pet trade. See how CISP tries to counter this threat.

Hawaii Volcanoes National Park. As I wrote in my blog of October 7, Hawaii Volcanoes National Park is fighting feral hogs, goats, and a plethora of invasive plants (the Park’s flora contains nearly twice as many exotic flowering plants as native species). The Park’s birds are threatened by two non-native diseases, avian pox and avian malaria. As noted in the earlier blog, Hawaii Volcanoes has also been invaded by koa wilt and `ohi`a rust; and is about to be invaded by `ohi`a wilt.

Web-based information from several parks in the western part of the continent focuses on the threat from invasive plants: Grand Canyon, Olympic, Yellowstone, and Yosemite. Redwoods National Park notes the damage caused by sudden oak death to its principal hardwood species, tanoak. Yellowstone National Park has a website describing its whitebark pine forests and mentioning that up to 30% of the taller whitebark pines have been attacked by white pine blister rust; I could find little information about the disease’s impact on the Park’s limber pines, which are also susceptible.

Yosemite National Park has a website with a table listing 16 non-native insects and pathogens that could threaten trees in the park. White pine blister rust is already present in the Park’s sugar pines. I am pleased to see that the website features goldspotted oak borer and the risk of pest introduction via firewood. I just wish Yosemite actually prohibited visitors from bringing firewood into the Park! And carefully restricted commercial suppliers! I addressed Yosemite’s failure to protect itself in my blog of 10 August.

The National Parks Conservation Association is the principal NGO that advocates for protection of the National parks. It issued a report in 2008 that found invasive species were a limited concern in 90% of the parks evaluated, a widespread or chronic concern in 38%. In Hawaii Volcanoes specifically, the natural resources were ranked in “poor” condition due primarily to non-native plants and animals.

Many individual parks have “Friends” groups ….

I ask these groups to help the National parks counter invasive species. To be effective, they need to go beyond the many volunteer “weed pulls” and outreach programs educating park visitors who might transport invasive species (for example, boaters and fishermen who can spread New Zealand mudsnails, rock snot, and invasive mussels; and campers who carry firewood that can transport pests). I ask them to also lobby for policies that would prevent invasions and for increase funding for the parks’ resource management programs (the programs that tackle invasive species). I suggest specifically that supporters of National parks advocate for improvements in programs run by the USDA’s Animal and Plant Health Inspection Service or the U.S. Fish and Wildlife Service. These agencies, more than any other, determine whether prevention succeeds or fails.

Posted by Faith Campbell

Cacti under Threat – Does No One Care?

Nearly 2 million square miles of ecologically significant and beautiful desert ecosystems straddle the U.S.-Mexico border regions. Cacti are either dominate or are extremely important components of these ecosystems. Two South American insects already present in the United States threaten to kill large numbers of these cacti and transform these desert ecosystems. Iconic species – prickly pears, saguaro, and organ pipe cacti – are at risk.

prickly pear cactus at Factory Butte; photo by S.E. Schlarbaum

Flat-padded prickly pear cacti of the genus Opuntia are threatened by the cactus moth, Cactoblastis cactorum.
In 1989, the cactus moth was found in southern Florida, to which it had spread from the Caribbean islands (Simonson 2005). Since then, it has spread west as far as southern Louisiana. Two small outbreaks on islands off Mexico’s Caribbean coast have been eradicated. If it reaches the arid regions of Texas, it is likely to spread throughout the desert Southwest.
In Florida, the cactus moth has caused considerable harm to six native species of prickly pear, three of which are listed by the state as threatened or endangered. In the American Southwest, at least 80 species of flat-padded prickly pears are at risk (Simonson et al. 2005) and there are more in Mexico, which is the center of endemism for Opuntia.
These cacti support a diversity of pollinators as well as deer, javalina (peccaries), tortoises, and lizards. Prickly pears also shelter packrats –which in turn are fed on by raptors, coyotes, and snakes; nesting birds and plant seedlings. Their roots hold highly erodible soils in place (Simonson 2005).
The U.S. Department of Agriculture began trying to slow the spread of the cactus moth in 2005 – 15 years after it was first detected in Florida (Mengoni Goñalons et al. 2014). However, the program never received an appropriation from Congress so funding was always inadequate. For several years, a patchwork of projects was stitched together: Mexico provided some funding; a volunteer network managed by Mississippi State University monitored lands along the Gulf Coast for the moth; and a laboratory operated by the Florida Department of Agriculture reared moths for research, sterile male releases and biocontrol host specificity testing.
The continuous funding problems led APHIS to abandon its regional program and focus on biocontrol, which is the only viable control measure in the desert Southwest where vulnerable cacti are numerous and grow close together. A newly described wasp, Apanteles opuntiarum (Mengoni Goñalons et al. 2014), is the most promising candidate.
Harrisia cactus mealybug might attack columnar cacti
The 2 million square miles of desert in Southwest United States and Mexico are home to more than 500 columnar cactus species in the Cactoideae (Zimmerman et al. 2010). Some are already endangered; others are totems of the desert, e.g., saguaro, organ pipe, and barrel cacti. The larger ones, particularly, play important ecological roles.
A second South American insect threatens columnar cacti in the Caribbean basin now and in the future could put others at risk in the American Southwest and Mexico: the Harrisia cactus mealybug (Zimmerman et al. 2010).
A mealybug in the genus Hypogeococcus has been killing several of the 13 columnar cactus species in southern Puerto Rico since 2005. Two are endangered species: Harrisia portoricensis and Leptocereus grantianus (USDA ARS). These cacti provide food or shelter for endemic bats, birds, moths and other pollinators (Segarra & Ramirez; USDA ARS). This mealybug is also now killing native cacti on the U.S. Virgin Islands (H. Diaz-Soltero pers. comm. August 2015).
Mealybugs in the same genus in Florida and Hawai`i do not attack cacti (University of Florida fact sheet; Hawai`i Department of Agriculture new pest report). In South America, though, insects in this genus feed on many columnar cacti, including ones in the genera Cereus, Echinopsis, Harrisia, Cleistocactus, Monvilea, and Parodia (USDA ARS; Zimmerman et al. 2010). Scientists are uncertain how many mealybug species are involved, which complicates efforts to determine the level of threat to columnar cacti on the U.S. mainland (H. Diaz-Soltero pers. com. August 2015). No one knows how vulnerable individual cactus species growing in the Southwest are to Hypogeococcus mealybugs (Golubov pers. comm. January 2011). Nor does anyone know whether natural enemies of mealybugs native to Mexico might also attack alien mealybugs and so prevent significant damage to native cacti (Zimmerman et al. 2010).
Still, the possible threat warrants studies to determine the vulnerability of these cacti to non-native mealybugs in the Hypogeococcus genus.
Meanwhile, scientists at the USDA ARS laboratory in Argentina have been searching for possible biocontrol agents but are stymied by the confusion over which mealybugs attach which cacti. Use of DNA sequencing and other tools should clarify these issues (H. Diaz-Soltero pers. comm. August 2015). However, no funds have been appropriated for this work, which has hindered progress (H. Diaz-Soltero pers. comm. August 2015).
To date, no organized constituency has advocated for protection of our cacti from these two pests. In the past I tried to persuade native plant societies, Nature Conservancy chapters, the leadership of the American Cactus and Succulent Society, and other groups that champion the desert to help lobby the Congress to fund USDA’s efforts. I was never successful.
Are Americans truly indifferent to the threat that many cacti in our deserts will be killed by non-native insects? Do they not realize that these threats must be countered before they reach the areas where cacti are dense and numerous?

Sources
California Plant Pest and Disease Report. 2005. Vol. 22 No. 1. Covering Period from July 2002 through July 2005.
Hawaii Department of Agriculture. 2006. http://hawaii.gov/hdoa/pi/ppc/2006-annual-report/new-pest-detections (accessed 11/1/10)
Mengoni Goñalons, C., L. Varone, G. Logarzo, M. Guala, M. Rodriguero, S.D. Hight, and J.E. Carpenter. 2014. Geographical range & lab studies on Apanteles opuntiarum (hymenoptera: braconiDae) in AR, a candidate for BC of Cactoblastis cactorum (Lepidoptera: Pyralidae) in North America. Florida Entomologist 97(4) December 2014
Segarra-Carmona, A.E., A. Ramirez-Lluch. No date. Hypogeococcus pungens (Hemiptera: Pseudococcidae): A new threat to biodiversity in fragile dry tropical forests. {title/org/other identifying information for Segarra-Carmona plus an entry for the pers. comm.}
Simonson, S.E., T. J. Stohlgren, L. Tyler, W. Gregg, R. Muir, and L. Garrett. 2005. Preliminary assessment of the potential impacts and risks of the invasive cactus moth, Cactoblastis cactorum Berg, in the U.S. and Mexico. Final Report to the International Atomic Energy Agency, April 25, 2005 © IAEA 2005
USDA Agriculture Research Service, Research Project: Biological Control of the Harrisia Cactus Mealybug, Hypogeococcus pungens (Hemiptera:pseudococcidae) in Puerto Rico Project Number: 0211-22000-006-10 Project Type: Reimbursable
Zimmermann, H.G., M.P.S. Cuen, M.C. Mandujano, and J. Golubov. 2010. The South American mealybug that threatens North American cacti. Cactus and Succulent Journal. 2010 Volume 82 Number 3

Posted by Faith Campbell