invasive species policy – Page 26 – Center for Invasive Species Prevention

Junk the international phytosanitary system? One seed breeder says yes.

If you have read my earlier work, you know that I think the international phytosanitary “system” is not working well to prevent introduction of novel arthropods and pathogens that attack naïve plant hosts in the new ecosystem. For example, see my blog in May on the study of introduced forest pests with Gary Lovett as senior author; my blog in April 2016 on Phytopththoras in Europe; discussions of the problems in my reports, Fading Forests II and Fading Forests III – available here.

the IPPC is located in Rome

One plant breeder has read the critiques by Clive Brasier (world-famous British forest pathologist) and others and apparently concluded that the solution is not to strengthen phytosanitary measures but to abandon them! He suggests that instead of attempting to prevent pest introductions, agriculture should instead rely on new breeding technologies to rapidly breed plants that are resistant to the introduced pest.

D. Zamir (who works at the Institute of Plant Sciences and Genetics, Faculty of Agriculture, The Hebrew University of Jerusalem) has published an article in Plos 1 Biology citing Brasier’s criticisms (see Dr. Brasier’s web link above and my Phytophthora blog). Zamir calls for the International Plant Protection Convention (IPPC) to launch a global plant breeding project. In his view, such a project would not only improve plant species’ resilience vis a vis pest attacks. It would also build the scientific capacity of countries with high biological diversity

Zamir says that the IPPC is waging a losing defensive strategy that imposes ever-more regulations on plant movement and exposes those who would like to move plants for various reasons to increasingly heavy penalties if they violate the rules. At the same time, the internet provides unlimited opportunities for anyone to obtain mail-ordered seed, often with free international shipping.

Citing Brasier, Zamir notes that the current phytosanitary system has the following flaws:

The system ignores the approximately 90% of pathogens that are unknown to science.
It assumes that potential hosts will be taxonomically related to those affected in the country of origin, whereas the host range may be much wider in the new environment.
Reliance on visual evaluations fails because pathogens might be present in a form that does not cause symptoms (e.g., spores).
Aggressive pathogens identified in a particular country might not be recognized as a risky pest by the international community because of inefficient global communication of such threats.

Zamir says that biological diversity drives improvements in crop productivity and resilience to diseases and environmental stresses. In his view, release of new varieties provides added value to consumers, producers, and the environment. Breeding programs often rely on the use of wild species and local varieties for gene mapping and rapid deployment of traits. However, Zamir complains, the international system hampers exchanges of seed among countries. It is often not possible to ascertain if the original seed used as a source of the traits was obtained in accordance with all the phytosanitary regulations. Zamir says that breeders often “cut through the red tape” by sending the seed through the mail without obtaining a phytosanitary certificate.

Zamir then proposes that people concerned about plant productivity and health in the face of growing trade volumes and vulnerability to insects and pathogens should abandon reliance measures intended to prevent introductions of pests and instead launch a massive plant breeding program.

While his focus is apparently on crop breeding, Zamir cites success in breeding elm trees resistant to the Dutch elm disease pathogens as proof that this approach can work – and that success depends on access to the full genetic variability of the target species.

Zamir concedes that he has not addressed issues of governance, financing, selection of the species to be included in the program, and how to involve the private sector.

Of course, movement of seeds across ecological barriers poses less of a risk of introducing an alien pest than does movement of whole plants or cuttings. For that reason, phytosanitary regulations governing seed movement are more lenient than those for plants and cuttings.

I consider Zamir to wildly underestimate the difficulty – nay, impossibility – of applying his approach. To date, efforts to breed trees resistant to individual pests have required decades of effort. The U.S. tree breeding system falls far short of what is needed to respond to pests already in the country (see Chapter 6 of Fading Forests III, available here). For example, American chestnut has benefitted from decades of devoted effort – but success in countering chestnut blight is not yet certain, and the tree is under attack by another half-dozen pests. (To see a reminder of how many tree taxa are under threat from non-native pests, go to the write-ups on the Don’t Move Firewood website or re-read articles by Lovett et al. or Aukema et al. 2010 — citations provided below.)

Even though modern genetic techniques, e.g., CRISPR –Cas9, seem to promise faster and cheaper breeding methods, how would breeding programs catch up to the tidal wave of new introductions?

Furthermore, few breeding programs for North American forest trees have yet proved a capacity to restore trees to the forest.

Finally, Zamir’s proposal would compound the existing equity problem. Already, the cost, environmental degradation, and other burdens of countering pest spread lie predominantly on the receiving society – including municipal tax payers and homeowners who must remove and replace trees killed by introduced pests (see Aukema et al. 2011.) Those who profit from international trade rarely pay directly. Zamir’s proposal would exacerbate that inequity by transferring all the risk of new introductions and cost of responding to new pests to the receiving ecosystem and the broad public. Those profiting from the trade would face next to no responsibility.

Fortunately, most plant breeders engaged in moving seed internationally have taken a more productive approach to adapting the international phytosanitary system to accommodate their business. The North American countries adopted a regional standard on the seed trade (RSPM# 36) in 2012. A draft global standard will soon be circulated for comments by the IPPC member countries.

As I have said before, I call on phytosanitary agencies and the multitude of stakeholders harmed by pest movement – including grant-making foundations; federal and state agencies; conservation non-governmental organizations; forest products companies; trade associations representing various aspects of international trade in plants, wood packaging, and other vectors; and urban tree programs and mayors – to work together to improve U.S. and international phytosanitary programs.

SOURCES

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)

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

Campbell, F.T. and S.E. Schlarbaum. Fading Forests I, II, and III at http://treeimprovement.utk.edu/FadingForests.htm

Lovett, G.M., M. Weiss, A.M. Liebhold, T.P. Holmes, B. Leung, K.F. Lambert, D.A. Orwig , F.T. Campbell , J. Rosenthal, D.G. McCullough, R. Wildova, M.P. Ayres, C.D. Canham, D.R. Foster, S.L. LaDeau, and T. Weldy. 2016. Nonnative forest insects and pathogens in the United States: Impacts and policy options. Ecological Applications, 0(0), 2016, pp. 1–19. DOI 10.1890/15-1176.1 Available at www.caryinstitute.org/tree-smart-trade

Zamir D (2016) Farewell to the Lose–Lose Reality of Policing Plant Imports. PLoS Biol 14(4): e1002438. doi:10.1371/journal.pbio.1002438 Published: April 19, 2016Available at http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.1002438 Or http://www.ncbi.nlm.nih.gov/pubmed/27093460

Posted by Faith Campbell

Emerald ash borer – crucial research needs funding!

ash tree dying after attack by emerald ash borer

We all know that the emerald ash borer (EAB) has caused enormous damage in the approximately 25 years since it was first introduced to Michigan and Ontario. (For more information, see writeup here. In brief, EAB has killed “untold millions” of ash trees across more than 170,000 square miles in 25 states and two provinces (map).
Apparently all North American ash are vulnerable – more than 20 species in Canada, the U.S., and Mexico. The genus Fraxinus is one of the most widespread on the continent. These trees’ deaths are causing changes in forest species composition, structure, and function. Hundreds of arthropod species that depend on the genus will be affected.

Nevertheless, forests with important ash components are still outside the infested area and deserve greater protection.

Also, ash trees are among the most common ornamental trees planted in U.S. cities and towns. The death of these trees show us that EAB also has imposed billions of dollars in costs on people who had no direct role in the insect’s introduction and spread. Several studies have proposed estimates:
o Communities in Ohio would likely incur costs up to $4 billion if all ash trees on public land were removed and replaced (Sydnor et al. 2007).
o Communities in four Midwestern states would have to pay an estimated $26 billion to remove and replace as trees growing in parks, private lands, and along streets (Sydnor et al. 2011).
o The cost of treating or removing only half of the affected urban and suburban trees across the anticipated range of EAB during the 10-year period from 2009 to 2019 would be $20 billion (Kovacs et al. 2011).

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

Over the 14 years since EAB was detected, scientists have learned much about the insect, its hosts, and its management. Early detection of new outbreaks remains difficult. However, traps and lures are more effective than even a few years ago. Other new tools also have been deployed, including strategies for protecting high value trees, and slowing the rate of ash mortality in urban and natural forests.

Four biocontrol agents have been released at sites across the invaded area, although it is too early to know how effective they will be in suppressing EAB populations and protecting ash trees.

The systemic insecticide emamectin benzoate controls EAB for up to three years. This means that municipalities and property owners can now save mature ash trees. Studies show that treating such trees costs less than removing dead trees and planting replacements (Herms and McCullough 2014).

Scientists in Ohio, Michigan, Kentucky, and Massachusetts are testing whether treating just some trees in forest settings can help protect nearby ashes.

One of the most important potential responses to this insect is to breed resistant ash trees. The USDA Forest Service and USDA APHIS have funded such efforts since 2005 – only three years after the insect was detected. Scientists have demonstrated that some ash species that have coevolved with the insect in Asia – especially Manchurian ash – are resistant to EAB attack. More recently, they have been studying how to cross-breed the resistant and non-resistant species and how to evaluate the hybrid progeny for genetic resistance.

Dr. Pierluigi (Enrico) Bonello and others at Ohio State and Wright State University are studying how Manchurian ash trees resist EAB attack. Their focus is on the chemicals present in the trees’ tissues – how they differ in Manchurian ash compared to North American species. These studies have found that Manchurian ash trees contain chemicals that decrease growth and survival of EAB larvae, and decrease the attractiveness of the tree to ovipositing females.
The Ohio team next needs to continue their progress towards identification of the specific chemicals involved, insert the genes that produce them into other ash tree genomes, and produce a large enough number of progeny to test whether the new trees’ genes provide the expected protection.

The team is also studying the other side of this equation – how EAB larvae neutralize defense mechanisms of vulnerable ash species and how these trees may be manipulated to interfere with these adaptations of EAB.. This is a long-term project that needs consistent and sustained support over many years to bring about real capacity for restoring disappearing ash populations.

Unfortunately, funding for this vitally important work is not assured. USDA APHIS (link to 101 on CISP) has funded the team’s work to date, but may no longer be in a position to do so. . After all, it is 14 years since EAB was detected and a decade since APHIS stopped trying to eradicate it. The goal now is to manage EAB in the forest and in urban settings, over the long term. This task logically should fall to the USDA Forest Service.

Both APHIS and the Forest Service are challenged by the need to respond to the introduction of ever more non-native tree-killing insects and diseases; by the need for programs to address pests already present; and by simultaneous reductions in agencies’ budgets. APHIS’ budget for managing all “tree and wood pests” has fallen from $76 million to $55 million since 2011 – a 28% reduction. The USFS’ research budget has fallen less, proportionately: from $307 million to $292 million (a 4% cut).
However, the USFS Research budget has never been generous in funding research on non-native invasive species. Annual totals for invasive species research have been between $5 and $5.6 million since 2012. EAB specifically has been funded at between $1.2 and $1.8 million.
(For a longer discussion of funding shortfalls and other impediments to programs intended to help our forests recover from EAB and other non-native pests, read Chapter 6 of Fading Forests III, available here)

The emerald ash borer is the most destructive and costly forest insect ever introduced to the United States. Surely the government agency responsible for protecting our forests should provide additional resources to counter this threat.

Sources:
Herms, D. A. and D. G. McCullough. 2014. Emerald Ash Borer invasion of North America: History, biology, ecology, impacts, and management. Annual Review of Entomology, Vol 59, 2014 59:13-30.

Kovacs KF, Mercader RJ,Haight RG, SiegertNW,McCulloughDG,Liebhold AM. 2011. The influence
of satellite populations of emerald ash borer on projected economic costs in U.S. communities, 2010–
2020. J. Environ. Manag. 92:2170–81

Sydnor TD, Bumgardner M, Subburayalu S. 2011. Community ash densities and economic impact
potential of emerald ash borer (Agrilus planipennis) in four Midwestern states. Arboric. Urban For. 37:84–89

Sydnor TD, Bumgardner M, Todd A. 2007. The potential economic impacts of emerald ash borer
(Agrilus planipennis) on Ohio, U.S., communities. Arbor. Urban For. 33:48–54
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

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