forest pests – Page 18 – Center for Invasive Species Prevention

Study finds “targetted” phytosanitary measures are effective in reducing introductions of plant pests

Figure 2 from the article:

The number of new pathogens discovered each year on 131 focal host plant species in New Zealand (closed circles) and the mean annual rate of pathogen arrival estimated from the model (solid blue line), with shading showing the 95% credible interval.

Benjamin A. Sikes and several coauthors (article available here; open access!) find that targetted biosecurity programs can reduce the establishment of nonnative pathogens even while global trade and travel continue to increase.

The study relies on data from New Zealand because that country has more than 150 years of data on phytosanitary policies and pathogen introductions. Do other countries have data that would support a comparative study in order to test the authors’ conclusions more generally?

The study is unusual in analyzing introductions of a variety of forms of pathogens (fungi, oomycetes, and plasmodiophorids) rather than invertebrates. Pathogens pose significant plant health risks but are notoriously difficult to detect. The study used data on plant-pathogen associations recorded in New Zealand between 1847 and 2012. It focused on hosts in four primary production sectors: crops (46 species, including wheat, tomatoes, and onions); fruit trees (30 species, including grapes, apples, and kiwifruit); commercial forestry (42 species, including pines and eucalypts); and pastures (13 species of forage grasses and legumes). In total, 466 pathogen species for which the first New Zealand record was on one of these 131 host plants were included in the study. The pathogens were assumed to have arrived on imports seeds or fresh fruits of plants in the same family as the 131 hosts in the various production sectors.

After calculating each pathogen’s probable date of introduction, the authors compared those dates to contemporaneous levels of imports and incoming international travellers. Sikes et al. applied statistical techniques to adjust their data to the fact that detection of pathogens is particularly sensitive to variation in survey effort.

Findings:

The annual arrival rate of new fungal pathogens increased exponentially from 1880 to ~1980 in parallel with increasing import trade volumes. Subsequently rates stabilized despite continued rapid growth in not only imports but also in arrivals of international passengers.
However, there were significant differences among the four primary production sectors.

Arrival rates for pathogens associated with crops declined beginning in the 1970s but slightly earlier for those associated with pasture species. These declines occurred despite increasing import volumes.
Arrival rates of pathogens that attack forestry tree species continued to increase after 1960.
Arrival rates for pathogens that attack fruit tree species remained steady while import volumes rose steadily

Sikes et al. attribute these contrasting trends between production sectors to differences in New Zealand’s biosecurity efforts. They record when phytosanitary restrictions targetting the four sectors were adopted and link those changes to reductions in numbers of pathogens detected a decade or so later. They conclude that targetted biosecurity can slow pathogen arrival and establishment despite increasing trade and international movement of people.

Regarding the contrasting situation of the forestry and fruit tree sectors, Sikes et al. note that while phytosanitary inspections of timber imports was initiated in 1949, it focussed primarily on invertebrate pests. In addition, surveys for pathogens on fruit tree and forestry species were less robust than in the cases of crop and pasture species, and the peak survey effort occurred several decades later – in 1980 for fruit trees, 2000 for forestry species.

Furthermore, pathogens of forestry and fruit tree species can be introduced on types of imports other than seeds and fresh fruits, including soil and live plant material (e.g., rootstock) and untreated wood products.

Sikes et al. say there is no evidence of slowed pathogen arrival rates resulting from imposition of post-entry quarantine to live plant material beginning in the 1990s. I find this very troubling. Post-entry quarantine is a high-cost strategy. Still, several plant pathologists have advocated adoption of this strategy because they believed it would be sufficiently more effective in preventing introductions of – especially! – pathogens as to be worthwhile. Do others have data with which to add to our understanding of this disturbing phenomenon?

The authors suggest that introductions of tree-attacking pathogens on rising imports of wood packaging might have swamped decreases in introductions via other vectors. They consider that implementation of International Standard for Phytosanitary Measures (ISPM) No. 15 in 2002 means it is too early to see its impact in detection data. As I have blogged several times, implementation of ISPM#15 by the United States, at least, has reduced presence of detected pests – primarily insects – by 52%. Little is known about the presence of pathogens on wood packaging – according to some experts, inspectors rarely even look for pathogens. So I think the authors’ suggestion might not fully explain the continuing introduction of pathogens that attack tree species used in plantation forestry in New Zealand.

Prof. Michael Wingfield of South Africa has written numerous articles on the spread of pathogens that attack Eucalyptus on seeds imported to establish plantations in various countries; one such article is available here. This seems a more likely explanation to me.

The study’s analysis demonstrated that the overall rate of non-native fungal pathogen establishment in New Zealand was more strongly linked to changes in import trade volume than to changes in numbers of international passengers arriving on the islands. Although Sikes et al. don’t explicitly raise the question, they note that New Zealand has put considerable effort into screening incoming people – which appears from these data to have a smaller payoff than imposing phytosanitary controls on imports.

Recent declines in surveys mean the authors must estimate current pathogen arrival rates. The data gaps exacerbate the inevitable uncertainty associated with the time lag between when an introduction occurs and when it is detected. They estimate that an average of 5.9 new species of fungal pathogens per year have established on the focal host plant species since 2000. They estimate further that 55 species of pathogens are present in New Zealand but have not yet been detected there.

I am quite troubled by the reported decline in New Zealand’s postborder pathogen survey efforts since about 2000. This appears very unwise given that the risk of new introductions of pathogens that attack fruit and forestry trees continues – or even rises! Indeed, scientists associated with the forestry industry note the risk to Douglas-fir and Monterrey (Radiata) pine plantations from the pitch canker fungus Fusarium circinatum – which could be introduced on imported seeds, nursery stock, and even wood chips. Radiata pine makes up 92% of softwoods planted – and exotic softwoods constitute 97% of the plantation forestry industry.

Furthermore, non-native pathogens threaten New Zealand’s unique forest ecosystems. Since this study focused on non-native plant hosts, it does not address the risk to native forest species. However, the threat is real: Kauri trees – the dominant canopy species in some native forest types – is suffering from a dieback caused by an introduced Phythopthora. Also, two other pathogens threaten the many trees and shrubs in the Myrtaceae family found in New Zealand – Puccinia rust (which is established in Australia but not New Zealand) or the Ceratocystis fungi causing rapid ohia death – both threaten native forests in Hawai`i, as discussed in a recent blog.

Posted by Faith Campbell

We welcome comments that supplement or correct factual information, suggest new approaches, or promote thoughtful consideration. We post comments that disagree with us — but not those we judge to be not civil or inflammatory.

Appropriations Update – Give A Big Round of Applause to the House Appropriations Committee

In mid-May, the House Committee on Appropriations adopted two bills crucial to funding efforts to counter tree-killing non-native insects and diseases. Please let them know you are grateful.

APHIS funding

The Agriculture appropriations bill funds APHIS (and other USDA agencies) for Fiscal Year 2019 (which begins on October 1). The new bill provides a total of $998,353,000 to APHIS, an increase of $16.4 million above the FY18 level and $259 million above the Administration’s request. ( I blogged about the Administration’s alarming request here.) You can find the bill here; the more informative report is posted here. Use search words to find specific APHIS programs.

The pest-related funding is apportioned among several areas:

Tree and Wood Pest Program. Unlike in previous years, the House bill does not cut funds for this program – which funds efforts to eradicate or contain the Asian longhorned beetle, emerald ash borer, and European gypsy moth. Instead, it maintains funding at the FY18 level of $54 million. Under the circumstances, this is good news. Thank you for your efforts to educate members of the House subcommittee on agricultural appropriations about this crucial program! (In past years, we relied on the Senate to restore funding for the Tree and Wood Pest Program.)

Specialty Crop Pests Program. The House increased funding by $10.8 million here, and specified that $15 million target the spotted lanternfly. This recently detected Asian leafhopper is spreading in southeastern Pennsylvania and was recently confirmed in Virginia’s Shenandoah Valley. It is a pest of native hardwood trees as well as of orchard and other crops.

Also, the Committee used its report to stress several concerns:

Access to emergency funding. In the report, the House Appropriations Committee reiterates its longstanding instruction that the USDA Secretary continue to use his authority to transfer funds from the Commodity Credit Corporation. They support using these funds – above and beyond appropriated funds – for the arrest and eradication of animal and plant pests and diseases that threaten American agriculture.

Brown Apple Moth vs. Emerald Ash Borer. Interestingly, the House Appropriations Committee encourages APHIS to engage state and international regulatory bodies as it moves to deregulate the light brown apple moth. The Committee expresses concern that if APHIS simply withdraws federal regulation without the necessary work with other officials, it will shift, not reduce, the regulatory burden. Then growers would carry the burden of preventing spread of the pest. I wish the Committee had made the same statement vis a vis the emerald ash borer! APHIS also plans to stop regulating this insect which continues to threaten still-uninvaded portions of the United States and Mexico.

Micornesia and Hawai’i. The Committee also instructs the Secretary of Agriculture to report to both the House and Senate Committees on Appropriations its progress implementing the Regional Biosecurity Plan for Micronesia and Hawai`i. This plan combines efforts by the U.S. Department of Defense, Department of the Navy, and the island governments to prevent transport of invasive species as a consequence of relocating military personnel from a base in Okinawa, Japan. More information is available here.

Forest Service funding

The Interior appropriations bill funds the US Forest Service (as well as Interior Department and Environmental Protection Agency).

Forest Health Management Program. The bill provides an increase of $19.5 million above FY18 levels for the forest health management program ($30 million above the Administration’s request). The Committee instructs the Forest Service to “work in concert with Federal agencies, States, and other entities to prioritize the allocation of these funds to address the greatest threats.” The emerald ash borer, “bark beetle” (which ones?) and cogon grass are expressly mentioned. The report is posted here. (It is unclear what actions the Forest Service is expected to take on the EAB, since regulations intended to curtail people from moving infested wood will soon be dropped by APHIS. The Forest Service could support breeding of ash trees resistant to the beetle.)

Forest Service Research. The Interior appropriations bill also maintained funding for Forest Service research at the FY18 level of $297 million – rather than cutting it to $259 million as advocated by the Administration. The Committee has called for the USFS to act within one year to “strengthen” its research program. The Committee expressly avoids endorsing several priorities advocated by Members of Congress while waiting for the Forest Service to implement this instruction.

If your representative is a member of the House Appropriations Committee (members listed here), please thank them for supporting APHIS’ and USFS’ programs. These funding increases shift several years of decline and are a true win for protecting our forests from non-native insects and pathogens!

Posted by Faith Campbell

The 2018 Farm Bill – It’s Complicated!

As you might remember, the Center for Invasive Species Prevention and the Vermont Woodland Owners Association last year proposed several amendments to the Farm Bill that we hoped would strengthen the U.S. Department of Agriculture’s programs on non-native insects, plant pathogens, and invasive plants. These proposed amendments are here and here.

Two of our amendments sought to strengthen funding for long-term strategies to counterpests and restore pest-depleted tree species to the forest. We intended these proposals to be implemented together. They were put forward as two proposals only because they fell into different sections, called “titles”, of the Farm Bill.

Our first proposal would create a grant program managed by the National Institute of Food and Agriculture (NIFA) to fund research focused on biocontrol and genetic manipulation of the pests; enhancement of host-resistance mechanisms for tree species; and development of other strategies for restoration. U.S. government agencies, state cooperative institutions, academic institutions with a college of agriculture or wildlife and fisheries, and non-profit organizations would all be eligible for funding.

Our second proposal would provide long-term funding to a similar array of organizations to support research into and deployment of strategies for restoring pest-resistant genotypes of native tree species to the forest. We suggested funds be drawn from the McIntyre-Stennis program. Successful grant applicants would be required to integrate several components into a cohesive forest restoration strategy:

Collection and conservation of native tree genetic material;
Production of sufficient numbers of propagules of pest-resistant native trees to support landscape scale restoration;
Site preparation in native trees’ former habitat;
Planting of native tree seedlings; and
Post-planting maintenance of the trees.

Furthermore, priorities for competitive grants issued by this second fund would be based on the level of risk to forests in the state where the activity would take place, as determined by the following criteria:

Level of risk posed to forests of that state by non-native pests, as measured by such factors as the number of such pests present there;
Proportion of the state’s forest composed of species vulnerable to non-native pests present in the United States; and
Pests’ rate of spread via natural or human-assisted means.

Several coalitions presented these two proposals – in various forms – to the House and Senate Agriculture committees earlier this year.

ACTION IN THE HOUSE OF REPRESENTATIVES

The Stefanik Amendment

In the House, Representative Elise Stefanik (R-NY21) inserted a modified version of CISP’s proposed amendments into the Farm Bill (H.R. 2) . Ms. Stefanik’s speech on the House floor introducing her amendment, and support of that amendment by Rep. Glenn Thompson of Pennsylvania and Agriculture Committee Chairman K. Michael Conaway (R-TX) can be heard here; scroll to time 25.16

The Stefanik amendment includes some of the key provisions advocated by CISP but it also differs in significant ways. That is, it relies on an existing grant-making program, the Competitive Forestry, Natural Resources, and Environmental Grants program. This program funds proposals pursuing numerous purposes, including pest management and genetic tree improvement. Rep. Stefanik’s amendment adds a new purpose, restoring forest tree species native to American forests that have suffered severe levels of mortality caused by non-native pests. It is unclear whether this approach will significantly increase resources available for breeding trees resistant to non-native pests.

Another difference is that institutions receiving funds would have to demonstrate that their activity is part of a broader strategy that includes at least one of the following components:

1) Collection and conservation of genetic material;

2) Production of sufficient numbers of propagules to support the tree’s restoration to the landscape;

3) Site preparation of former native tree habitat;

4) Planting; and

5) Post planting maintenance

The original CISP proposal required any funded program to incorporate all of these components.

The Stefanik amendment would award grants based on the same three criteria proposed by CISP.

While we are disappointed that research underlying tree restoration has merely been added to an already-long list of purposes under the Competitive Forestry, Natural Resources, and Environmental Grants program, this approach might be the best we can hope for. There had been considerable opposition to our proposal because it would have changed the formula under which McIntire-Stennis funds are apportioned to the states. Adopted in 1962, the existing formula is based on each state’s

1) area of non-Federal commercial forest land;

2) volume of timber cut annually;

3) total expenditures for forestry research from non-Federal sources;

4) base amount distributed equally among the States.

The Faso Amendment

The House also accepted an amendment sponsored by Rep. John Faso (R-NY19) that would require APHIS and the US Forest Service to collaborate on surveillance to detect newly introduced tree-killing pests. The agencies would also report to Congress by 2021 on which pests are being detected on imports of wood packaging and living plants (APHIS’ so-called “plants for planting”) and the geographic origins of those pests. Rep. Faso’s speech introducing the amendment and supportive statements by Reps. Thompson and Conaway can be heard here; scroll to time 32 (immediately after the Stefanik amendment).

The Welch Bill

Meanwhile, as I blogged earlier, Rep. Peter Welch (D-VT) has introduced a separate bill (H.R. 5519) that contains modified versions of several CISP proposals.

Rep. Welch’s bill would do two things: strengthen APHIS’ access to “emergency” funds to respond to invasive pests, and create a competitive grant program to support research on biological control of plant pests or noxious weeds, enhancing host pest-resistance mechanisms, and other strategies for restoring tree species. These studies must be part of comprehensive forest restoration research. Eligible institutions would include federal and state agencies, academic institutions, and nonprofit organizations. Funding would come from a USDA corporation, the Commodity Credit Corporation so they would not be subject to annual appropriations.

The House has taken no action on Rep. Welch’s bill.

THE CURRENT STATUS OF THE FARM BILL – AND CISP’s BOTTOM LINE

On 17 May, the House of Representatives failed to pass the Farm Bill. No Democrats voted for the bill. About 30 Republicans also voted against the bill – not because they objected to its contents, but because they wanted to force a vote on an immigration bill. House leaders now promise a new vote on the Farm Bill on June 22nd.

Is this good news? As I said, it is complicated! The House bill contains several provisions to which there is significant opposition. The most controversial is a requirement that recipients of food stamps prove that they are working. Other provisions – which have not received much attention in the media, would:

Allow the U.S. Forest Service and the Interior Department’s Bureau of Land Management to decide for themselves whether an activity might “jeopardize” an endangered species (eliminating the need to consult with the U.S. Fish and Wildlife Service or National Marine Fisheries Service) (Section 8303);
Allow the U.S. Forest Service and Bureau of Land Management to avoid preparing an environmental assessment under the National Environmental Policy Act (NEPA) for a long list of actions which currently must be assessed. That is, they could claim a “categorical exclusion” when taking a wide variety of “critical” actions aimed at addressing several goals. These include countering insect and disease infestations, reducing hazardous fuel loads, protecting municipal water sources, improving or enhancing critical habitat, increasing water yield, expediting salvage of dead trees following a catastrophic event, or achieving goals to maintain early successional forest. These “categorical exclusions” would apply to projects on up to 6,000 acres. (Sections 8311 – 8320); and
Require the EPA Administrator to register a pesticide if the Administrator determines that the pesticide, when used in accordance with widespread and commonly recognized practices, is not likely to jeopardize the survival of a species listed under the Endangered Species Act or to alter critical habitat. Unlike under current law, the Administrator would not be required to consult with the U.S. Fish and Wildlife Service or National Marine Fisheries Service when making such determinations (Section 9111).

The Endangered Species Act, adopted almost unanimously in 1973, requires such “consultations” because experience had shown that agencies proposing projects tended to underestimate the damage that they might cause to imperiled species. NEPA is one of the foundational statutes of U.S. environment protection; it was adopted in 1970. Finally, the EPA Administrator is supposed to decide whether to allow pesticide use based on science, per a much weaker but still important environmental protection statute, the Federal Insecticide, Fungicide, and Rodenticide Act (originally adopted in 1910; significantly amended in 1972).

Is getting an imperfect and partial program that might stimulate breeding of tree species resistant to invasive pests worth accepting this level of damage to fundamental environmental programs?

I don’t think so.

We don’t yet know what the Senate will do. We hope the Senate bill will support strong conservation programs – including strengthening APHIS and research into and application of long-term strategies such as resistance breeding – while not undermining the foundations of our Nation’s conservation and environmental programs.

Meanwhile, the House should rewrite the Farm Bill to remove the objectionable provisions.

Posted by Faith Campbell

Update on Beech Leaf Disease – a Threat Lacking Adequate Funding and Official Action

last year’s leaves showing symptomatic striping (F.T. Campbell)

Back in December I blogged about beech leaf disease, a disease affecting American beech in northeastern Ohio and neighboring parts of Pennsylvania and New York, as well as across Lake Erie in Ontario.

[For more information and photos of symptoms, visit

http://forestry.ohiodnr.gov/portals/forestry/pdfs/BLDAlert.pdf or

https://www.cleveland.com/metro/index.ssf/2017/12/beech_leaf_disease_discovered.html]

Scientists do not know what is causing the disease. So far it’s only clear that it appears to have been introduced to a single site and is spreading. At the beginning of May I participated in a workshop providing the most recent information on beech leaf disease.

workshop participants (budbreak was later than usual, so we could not observe deformed leaves) (F.T. Campbell)

Over the past three or four years, scientists have tried hard to understand the disease, its causes, and its likely prognosis. For example, scientists from the U.S. Department of Agriculture and the State of Ohio have looked for insects, fungal pathogens, bacteria, viruses, nematodes, phytoplasmas – all without finding a causative agent. Attention is currently focused on a previously undescribed nematode in the Litylenchus genus. The only other species in this genus is a foliar feeder found in New Zealand. Studies continue, with most scientists tackling the problem without special funding.

Beech is a very important component of the forests of northeastern Ohio. Beech ranks third in number of stems per acre; second for “shrubs”. Consequently, scientists working for Lake Metroparks and Cleveland Metroparks continue to monitor spread of the disease and its impacts. Symptoms – deformed leaves – were first detected in 2012. In 2017, the results of a long-term vegetation monitoring project revealed that of 307 plots with beech present, 154 had symptomatic trees. Of the symptomatic plots, 49% of beech stems were affected. While initially only small trees had been killed, more recently some larger ones have died and others bear only very few leaves. Leaves with light, medium, or heavy symptoms of infection – as well as asymptomatic leaves – can occur on the same branch of an individual tree.

The disease seems to spread faster between stems along the interlocking roots of beech clone clusters.

Weather does not appear to be a factor, as the disease has spread every year despite great variations in heat and cold as well as levels of moisture.

Preliminary versions of a mathematical model of the disease’ spread indicates that approximately 90% of monitoring plots deployed across the full 24,000 acres of Cleveland Metropark system will be infected within 10 years.

Cleveland Metroparks has initiated intensive monitoring of a subset of 13 plots in order to clarify the disease’s impact. Monitoring revealed a 4% mortality rate from 2015 to 2017. More than half of these plots now have dead beech that had previously been symptomatic. Most are small trees less than 4.9 cm dbh. Efforts to obtain funding from the USFS Forest Health program have so far failed.

The disease – whatever its cause! – appears to be moved by trade in nursery plants. An Ontario retailer received – and rejected – a shipment of diseased beech from an Ohio nursery. Lake County, Ohio, has many nurseries that grow and ship European beech (which can also be infected by beech leaf disease). These nurseries are reported to be cooperating with Ohio authorities. No official entity has imposed regulatory restrictions – not any of the states or provinces with the disease present or threatened by it; nor USDA APHIS or the Canadian Food Inspection Agency (CFIA).

Another threat to beech also not under regulation

CFIA has also not imposed a federal quarantine on another non-native pest killing beech, the European leaf-mining weevil, Orchestes fagi. First discovered in Halifax in 2012 – probably 5 years after its introduction – it has since spread throughout Nova Scotia. The weevil kills beech over 3 – 5 years.

New information added in June: according to Meurisse et al. (2018), the weevil overwinters under the bark of beech and trees that are not hosts, so it can be transported by movement of firewood and other forms of unprocessed logs and branches. [Meurisse, N. D. Rassaati, B.P. Hurley, E.G. Brockerhoff, R.A. Haack. 2018. Common Pathways by which NIS forest insects move internationally and domestically. Journal of Pest Science. https://doi.org/10.1007/s10340-018-0990-0]

The Importance of American Beech – and Protecting It

Beech is an extremely important tree in northern parts of the United States and Canada east of the Great Plains. It is co-dominant (with sugar maple) in the Northern Hardwood Forest [see two maps]. A summary of the species’ ecological importance can be found in Lovett et al. 2006. Forest Ecosystem Responses to Exotic Pests and Pathogens in Eastern North America. BioScience Vol. 56 No. 5.

native range of American beech; USFS map

Consequently, I am most distressed by the lack of attention to these new threats to the species. It is true that regulating an unknown disease agent (as would be the case with beech leaf disease) stretches traditional policy practice and possibly legal authorities. Furthermore, it has not yet been demonstrated that the disease can kill mature beech. However, neither of these caveats applies to the weevil, which is an identified species that has been documented to kill mature trees.

U.S. phytosanitary officials (the National Plant Board) will meet in Cleveland (!!) in August. Will the several state officials and their APHIS colleagues discuss how to address this new threat? Will any funds be made available to expand efforts to understand the disease, its spread, and possible measures to curtail it?

healthy beech, northern Virgina (F.T. Campbell)

Posted by Faith Campbell

Mixed News on Pest Dangers

‘ōhi‘a tree in flower

Worsening Threats to Hawaii’s Rich – and Rare — Native Forests

As I have written in previous blogs (October 2015; October 2016), the beautiful ‘ōhi‘a lehua (Metrosideros polymorpha) tree is ecologically and culturally the most important tree n the Hawaiian Islands. ‘Ōhi‘a trees dominate approximately 80% of Hawai`i’s remaining native forest. Loss of the species could result in significant changes to the structure, composition, and, potentially, the function, of forests on a landscape level. ‘Ōhi‘a forests are home to the Islands’ one native terrestrial mammal (Hawaiian hoary bat) as well as about 100 plant species listed as endangered by the U.S. Fish and Wildlife Service. Also 30 species of forest birds – in particular, the unique endemic honeycreeper subfamily — depend on ‘ōhi‘a. Eighteen of 19 extant Hawaiian honeycreepers in the main Hawaiian islands, including 12 of 13 bird species listed as endangered by the U.S. Fish and Wildlife Service, depend on ‘ōhi‘a for critical habitat.

Unfortunately, the threat to ‘ōhi‘a trees from three fungi appears to be rising.

“Rapid ‘ōhi‘a death” is caused by two fungi, Ceratocystis lukuohia and C. huliohia (formerly considered to be strains of Ceratocystis fimbriata). Rapid ‘ōhi‘a death has spread since 2010 to most districts of one island: Hawai`i or the “Big” Island. The total area affected is 135,000 acres. Still, most ʻōhiʻa forest on Hawai`i is still healthy, and the disease has not yet been found on any of the other islands. Scientists have begun exploring trees’ varying susceptibility and the possibility of breeding more resistant trees to be used for restoration. For more information, read the recently updated description here.

Ōhi‘a trees are also under attack by a third introduced fungus, called ‘ōhi‘a rust, guava rust, or myrtle rust. This is caused by Austropuccinia psidii (formerly named Puccinia psidii). Ōhi‘a rust has been established on all the Hawaiian islands since 2005. Until recently, it had caused little damage to ‘ōhi‘a – although it attacks several additional native plant species and has devastated the endangered endemic plant Eugenia koolauensis. This shrub can reproduce now only in nurseries where it can be treated for the fungus. In late 2017, an outbreak of the disease caused widespread defoliation and mortality of ‘ōhi‘a across hundreds of acres in at least four locations on windward portions of two islands, O‘ahu and Moloka‘i. It is not yet known whether this new damage resulted from introduction of a new, more virulent strain or from a period of unusually wet weather creating more favorable conditions for the fungus. For more information, read the recently updated description here. (Myrtle rust threatens plants in the Myrtaceae family across the Pacific; more than 450 species have been identified as hosts. Some species in Australia have been severely affected.)

laurel-wilt killed swamp bay in the Everglades

Severe Attacks on Redbay and other Laurels in the Southeast.

Since the turn of the century, redbay trees (Persea borbonia) in coastal regions of the Southeast have been dying because of laurel wilt disease. This is caused by the fungus Raffaelea lauricola, which in turn is vectored by the redbay ambrosia beetle (Xyleborus glabratus). Both the beetle and disease have spread rapidly since there were detected in 2002 near Savannah, Georgia. The disease now is found in eight states, reaching from eastern North Carolina south along most of the Florida peninsula; across the Gulf states with several locations in Alabama and Mississippi; and to isolated outbreaks in Louisiana and Texas. Already an estimated 320 million trees – nearly one-third of all redbays – have been killed. Mortality is highest where the disease first became established: Georgia (two-thirds of redbays killed), South Carolina (42% of redbays killed), and Florida (36% of redbays killed). In contrast, redbay mortality appears to be quite low in Alabama and Mississippi although mortality caused by disease might have been masked by application of fire or other silvicultural practices.

Other forest trees and shrubs in the Lauraceae family are also at risk. These include swamp bay (Persea palustris), which contribute greatly to the biological diversity of the “tree islands” scattered through the Everglades; sassafras (Sassafras albidum), which occupies a large range reaching into Michigan and southern New England; and two rare species – pondspice (Litsea aestivalis) and the federally listed pondberry (Lindera melissifolia). Northern spicebush (Lindera benzoin), another shrub in the Lauraceae family, does not attract the beetle so it is unlikely to sustain disease. In the West, California bay laurel has been determined by laboratory studies to be vulnerable.

Redbay is important to wildlife and has some use in horticulture. However, most attention has focused on the threat to avocados (Persea americana); the disease was detected in commercial orchards in 2012.

Concerned about loss of this ecologically important tree, scientists have begun efforts to breed redbays that are resistant to, or tolerant of, the disease. In addition to efforts by university scientists, the newly formed consortium Forest.Health (https://forest.health/) has listed redbay as a high priority for resistance breeding. For more information, read the updated description here.

initial damage caused by Kuroshio shot hole borer in Tijuana River Valley; I lack access to photos of recovery. Photo by John Boland

Hope in southern California – possible ecological limits to shot hole borer / fungal disease

John Boland, an ecologist who has studied southern California riparian wetlands for decades, reports that willows in the Tijuana River are recovering from attack by the Kuroshio shot hole borer and the fungi it vectors. After two years, the beetle-vectored disease had infested 88% of the willows in the valley (a total of 355,510 trees). An estimated 24% of the willows had been killed (95,791 trees). Nearly all of the infested and killed trees grew in the wettest parts of the riparian forests. (Photo above illustrates damage at this stage of the invasion.)

However, 71,280 of the willow trees have resprouted. By late 2017, these resprouts had created a new forest canopy that was about 5 meters tall. (Previously, the canopy had been about 20 meters tall). The median rate of infestation of these resprouting willows was 6% in 2017, down from 97% in 2015-2016. Some insect boring holes have healed.

In contrast, willows growing in drier parts of the valley were rarely attacked initially, but are now increasingly infested. In 2017, the median infestation rate was 78%, up from 9% in 2015-16. However, few trees have been killed.

Dr. Boland believes that the severity of the initial attack reflected the vulnerability of “soft trees”. Trees growing in the wetter parts of the Tijuana River Valley are inundated by sewage from the Mexican city. As a result of this artificial fertilization, they grow quickly and their wood is less dense.

For more information about the Kuroshio and phytophagous shot hole borers and their associated fungi, read the description here.. Dr. Boland’s study has been made available to participants in the southern California emerging forest pest groups but I cannot find a publicly available source on the Web.

Posted by Faith Campbell

APHIS Nursery Stock Regulations (Q-37) – Modernization Finally Completed!

citrus longhorned beetle – entered country several times in imported bonzai plants

After about 20 years, APHIS has finalized important changes to the regulations which govern imports of living plants (what they call “plants for planting”; the regulation is sometimes called “the Quarantine 37” rule). The new regulation takes effect on April, 18, 2018.

I congratulate APHIS on this important achievement!

[Twenty years is a long time – so changes happen. When APHIS released its Advance Notice of Proposed Rulemaking (ANPR) in December 2004 and its proposed rule in April 2013, I was employed by The Nature Conservancy and submitted comments for that organization. I will refer to those earlier comments in this blog. However, I now represent the Center for Invasive Species Prevention, so my comments here on the final regulations reflect the position of CISP, not the Conservancy.]

APHIS’ 2004 ANPR came after years of preparation. Then, more than eight years passed until the formal proposal was published on April 25, 2013. Comments were accepted from the public until January 30, 2014. During this nine-month period, 17 entities commented, including producers’ organizations, state departments of agriculture, a foreign phytosanitary agency (The Netherlands), private citizens, and The Nature Conservancy. [You can view the ANPR and proposal, comments on these documents, and APHIS’ response here — although you need to click on “Restructuring of Regulations on the Importation of Plants for Planting” and then “Open Docket Folder” to pursue the older documents.]

In the beginning, APHIS had a few goals it hoped to achieve: to allow the agency to respond more quickly to new pest threats, to apply practices that are more effective at detecting pests than visual inspection at points of import, and to shift much of the burden of preventing pest introductions from the importer and APHIS to the exporter.

Progress has been made toward some of these goals outside this rule-making. APHIS instituted a process to temporarily prohibit importation of plants deemed to pose an identifiable risk until a pest risk assessment has been completed (the NAPPRA process). APHIS has further enhanced its ability to act quickly when a pest risk is perceived by relying increasingly on “Federal Orders”.

At the same time, APHIS participated actively in efforts by international phytosanitary professionals to adopt new “standards.” These define a new approach to ensure that plants in international trade are (nearly) pest-free. Both the North American Plant Protection Organization’s regional standard (RSPM#24) and the International Plant Protection Organization’s global standard (ISPM#36) envision a system under which countries would no longer rely primarily on inspections at ports-of-entry. Instead, they would negotiate with the supplier or exporting country to develop programs to certify that growers’ pest management programs are effective. Both standards detailed: 1) how the place of production might manage pest risk and ensure traceability of plants; 2) how the importing and exporting countries might collaborate to administer the program; 3) how audits (including site visits) would ensure the program’s efficacy; and 4) what actions various parties might take in cases of noncompliance.

It was hoped that these international standards would lead to widespread adoption of “integrated pest management programs” composed of similar requirements – similar to the impact of ISPM#15 for wood packaging. However, living plants are more complex pest vectors than the wooden boards of crates and pallets, so each country was expected to negotiate its own specific programs – something not encouraged for wood packaging.

APHIS’ decades-long effort to amend its regulations is warranted because of the high risk of non-native insects and – especially – pathogens being introduced via international trade in living plants. U.S. examples include white pine blister rust, chestnut blight, dogwood anthracnose, and sudden oak death (all described briefly here )

dogwood anthracnose

According to Liebhold et al. 2012 (full reference at end of blog), 12% of incoming plant shipments in 2009 were infested by a quarantine pest. This is an approach rate that is 100 times greater than the 0.1% rate documented for wood packaging (Haack et al. 2014). I have discussed the living plant introductory pathway and efforts up to 2014 to get it under control in my report, Fading Forests III.

Shortcomings of the Final Q 37 Rule

So – how well does this final rule meet APHIS’ objectives?

First, will it shift much of the burden of preventing new pest introductions from the importer and APHIS to the exporter, while ensuring the system’s efficacy? In my view, on behalf of CISP, it falls short.

The new rule sets up a process under which APHIS might require that some types of imported plants be produced and shipped under specified conditions intended to reduce pest risk. However, non-American entities have little incentive to protect America’s natural and agricultural resources and from invasive species. So any new process needs severe penalties for violators.

We have seen how widespread and persistent compliance failures are for wood packaging under ISPM#15. http://nivemnic.us/wood-packaging-again-11-years-after-ispm15-problems-persist/ For this reason, I (on behalf of the Conservancy) had suggested that APHIS formally adopt a specific goal of “no new introductions”. I recognized that this goal was unachievable per se, but suggested that it should stand as a challenge and be the basis for adopting stringent restrictions on plant imports. I suggested limiting plant imports to those either a) produced under integrated pest management measures systems (verified by third-party certification) or b) plants brought into facilities operating under post-entry quarantine conditions — and following other best management practices that had been developed and supervised by independent, scientifically-based bodies.

In my current view, APHIS’ regulation falls far short of either this goal of shifting burdens or setting a truly stringent requirement. In fact, APHIS has explicitly backed away from its own original goals and procedures.

The new regulation does authorize APHIS to choose to set up import programs under which the exporting country agrees to produce plants for the U.S. market under a system of integrated pest risk management measures (IPRMM) approved by APHIS. In accordance with the international standards, the programs established under this new power will address how the place of production will manage pest risk and ensure traceability of plants; how APHIS and the exporting country will administer the program; how plant brokers will ensure plants remain pest-free while in their custody; how audits will be performed to ensure program efficacy; and what actions various parties will take in cases of noncompliance.

How efficacious this new approach will be in preventing new introductions will depend on how aggressive APHIS is in both choosing the plant taxa and places of-origin to be managed under such IPRMM programs and in negotiating the specific terms of the program with the exporting country.

It is discouraging that APHIS has ratcheted down how frequently it expects to rely on the IPRMM approach. In the explanatory material accompanying the final regulation, APHIS clarifies that did not intend that IPRMM would be used for all imports of living plants. The IPRMM framework is described as only one of several means to achieve the goal of preventing introduction of quarantine pests. APHIS will choose the “least restrictive measures” needed to prevent introduction of quarantine pests. To clarify its position, APHIS changed the introductory text to indicate that IPRMM will be applied when such measures are necessary to mitigate risk – that is, “when the pest risk associated with the importation of a type of plants for planting can only be addressed through use of integrated measures.” [Emphases added]

The final rule is also discouraging in some of its specifics.

Whereas the draft regulation specified steps that places of production must take to ensure traceability of the plants they produce, in the final regulation the traceability elements specified in each IPRMM agreement will depend on the nature of the quarantine pests to be managed. Again, APHIS seeks to ensure that its requirements are not unnecessarily restrictive.
Although the international standard had specified severe penalties when a grower or broker violated the terms of the IPRMM agreement, APHIS proposed to base the regulatory responses to program failures on existing bilateral agreements with the exporting country. Despite the Conservancy’s plea that APHIS follow ISPM#36 in adopting more specific and severe penalties, APHIS has not done so. The one bright spot is that APHIS may verify the efficacy of any remedial measures imposed by the phytosanitary agency of the exporting country to correct problems at the non-compliant place of production. [Emphasis added]
APHIS is relaxing the detailed requirements for state post-entry quarantine agreements – despite the Conservancy’s concern that such agreements’ provisions could be influenced by political pressure and other nonscientific factors.

Two Improvements

I am pleased that APHIS has retained requirements applied to plant brokers, despite one commenter’s objections. Brokers handling international shipments of plants grown under an IPRMM program must both handle the plants themselves in ways that prevent infestation during shipment and maintain the integrity of documentation certifying the origin of the plants. A weakness, in my current view, is that APHIS will allow brokers to mix consignments of plants from more than one producer operating under the IPRMM program. APHIS does warn that if non-compliant (infested) plants are detected at import, all the producers whose plants were in the shipment would be subject to destruction, treatment, or re-export.

A major improvement under the new regulation is that APHIS will now operate under streamlined procedures when it wishes to amend the requirements for importing particular plants (whether a taxon, a “type”, or a country of origin). Until now, APHIS has been able to make such changes only through the cumbersome rulemaking process, Instead, APHIS will now issue a public notice, accept public comments, and then specify the new requirements through amendment of the “Plants for Planting Manual” [ https://www.aphis.usda.gov/import_export/plants/Manuals/ports/downloads/plants_for_planting.pdf ] APHIS estimates that such changes can be finalized four months faster under the new procedure.

A Final Caveat

Finally, APHIS needs to be able to measure what effect the new procedures have on preventing pest introductions. Such measurement depends on a statistically sound monitoring scheme. APHIS has stated in some documents that the current Agriculture Quarantine Inspection Monitoring (AQIM) system doesn’t serve this purpose. APHIS needs to develop a valid monitoring program.

References

Haack RA, Britton KO, Brockerhoff EG, Cavey JF, Garrett LJ, et al. (2014) Effectiveness of the International Phytosanitary Standard ISPM No. 15 on Reducing Wood Borer Infestation Rates in Wood Packaging Material Entering the United States. PLoS ONE 9(5): e96611. doi:10.1371/journal.pone.0096611

Liebhold, A.M., E.G. Brockerhoff, L.J. Garrett, J.L. Parke, and K.O. Britton. 2012. Live Plant Imports: the Major Pathway for Forest Insect and Pathogen Invasions of the US. www.frontiersinecology.org

Posted by Faith Campbell

Action on the Threat from Phytophthoras in Restoration Plantings

In July 2016 I blogged about the risk that native plant nurseries in California might spread various Phytophthoras to natural areas through use of infected plants used in restoration plantings.

In response to this threat, the California Oak Mortality Task Force has formed a Phytophthoras in Native Habitats Work Group to protect wildlands and assist the restoration industry in adopting practices to ensure they are producing “clean” plants.

The California Native Plant society (CNPS) adopted a policy to promote propagation practices that help prevent plant diseases. CNPS also established its own Ad Hoc Committee on Phytophthoras to address the same threat.

Numerous resources, including guidelines for nursery management, restoration plantings, summaries of committee meetings, photographs, etc., are posted at this website.

As I described in the July 2016 blog, Phytophthora pathogens have been detected in nurseries in other states, including Maryland, Minnesota, North Carolina, Oregon, and Tennessee. Doubtless nurseries in additional states also harbor damaging pathogens.

I’m not aware of action by regulatory officials, nursery owners, or conservation practitioners in these other states to evaluate and address this threat? Are you?

Posted by Faith Campbell

EU1 Genetic Lineage of Sudden Oak Death Persists in Oregon, Threatens Douglas-fir

In 2015 I blogged about Oregon’s first-ever detection of the EU1 strain of the sudden oak death pathogen – Phytophthora ramorum – in the forest. We know that P. ramorum has four genetic strains. Until this discovery, all P. ramorum infections in North American forests belonged to the NA1 strain.

In response to the 2015 detection, the Oregon Department of Forestry immediately began efforts to eradicate the EU1 infestation. This program was funded in part by the USDA Forest Service Forest Health Protection program and APHIS.

Unfortunately, the EU1 strain persists – and has spread. In 2017, six of ten streams in the state found to harbor P. ramorum contained the EU1 lineage. A total of 119 trees infected by the EU1 strain grow in five separate sites. Infections on 43 additional trees are still being tested to determine their lineages. Under the Oregon eradication protocols, 371 acres of private and state-owned properties will be affected by management targetting the EU1 lineage.

This news is alarming for two reasons.

First, the EU1 lineage is more aggressive than the more common NA1 strain. For example, the EU1 lineage in Europe kills several types of conifers, including western hemlock (Tsuga heterophylla). In Oregon, the EU1 strain has been found to infect both Douglas-fir (Pseudotsuga menziesii) and grand fir (Abies grandis) (LeBoldus et al. 2017). Douglas-fir is, of course, the foundation of the wood products industry in the West.

Second, the EU1 lineage is of the opposite mating type as NA1, creating the potential for sexual reproduction and increased variability in the pathogen population. (Sexual reproduction in P. ramorum can occur only when opposite mating types meet; in the absence if opposite mating types, all reproduction is clonal.)

The Oregon Department of Forestry continues eradication efforts. The program has been completed at one site; efforts at the other four known sites are a priority this year. Funding and resource constraints mean that sites infected by the more widespread NA1 strain are not likely to be treated this year. (ODF has approximately $1,375,000 available for eradication efforts in FY 2017-18.) No mention has been made of whether the USDA Forest Service or APHIS will provide assistance.

COMTF Newsletter March 2018

The EU1 pathogen probably spread to the original infected tree from a small private nursery nearby. That nursery had been reported to be infected with the EU1 lineage of P. ramorum in 2012. As I noted in my earlier blog, this infection confirms fears that contaminated nurseries can spread the pathogen into the forest.

SOURCES

California Oak Mortality Task Force newsletter [http://www.suddenoakdeath.org/news-and-events/newsletter-archive/ ] April 2015 and March 2018.

LeBoldus, J.M.; Sondreli, K.L.; Sutton, W.; Reeser, P.; Navarro, S.; Kanaskie, A.; and Grünwald, N.J. 2018. First Report of P ram Lineage EU1 Infecting Douglas-Fir and Grand Fir in OR. Plant Disease. 102(2): 455. [summarized in the California Oak Mortality Task Force Newsletter, March 2018, available here. [link]

Posted by Faith Campbell

Help Fund Priority Tree-Protection Programs

Your help is needed to prevent cuts to vitally important programs that protect America’s forests from non-native insects and pathogens.

USDA APHIS

The USDA Animal and Plant Health Inspection Service (APHIS) is responsible for preventing introductions of new pest that threaten plants – including forest trees — and for carrying out programs to eradicate or contain those that slip through their safeguards. I have blogged often about the unacceptable level of risk that the agency accepts, which enables new pests to be introduced. For examples, search “international trade” or “invasive species policy” on this site.

To see the President’s budget proposal, download the USDA budget justification here; search for “animal and plant”]

APHIS’ most important programs to counter tree-killing pests are funded through the “tree and wood pest” and “specialty crops” accounts. The former account pays for efforts to eradicate the Asian longhorned beetle (ALB), and to slow the spread of the emerald ash borer (EAB). As part of the latter program, it also funds APHIS’ engagement in regulating movement of firewood from quarantined areas.

For several years, the “tree and wood pest” account has been funded at $54 million. This is not sufficient, but we now face worse. The Administration has proposed cutting funding for the “tree and wood pest” account by more than half (from $54 million to $25 million). This level of funding would not even maintain the ALB eradication effort!

USDA smokejumpers search for ALB

The specialty crop account funds APHIS program to prevent sudden oak death from being spread via the nursery trade. It is slated for a cut of 18.7% (from $172 million to $139 million).

The Administration has proposed cuts to other programs that also would undermine protection for forest trees:

24% cut (from $21 million to $16 million) to methods development. This is the program under which APHIS develops new techniques for detecting, monitoring, and controlling pests.
5% cut (from $27 million to $22 million) to funding for pest detection. It is counterproductive to reduce programs to detect pests, since early discovery is crucial to successful eradication.

APHIS funds work on the spotted lanternfly (in Pennsylvania) and the polyphagous and Kuroshio shot hole borers (in California) through Section 10007 of the Farm Bill. The Farm Bill sets a funding limit for each year that is not subject to annual appropriations so these programs are not at immediate risk of being defunded. Also, APHIS can request emergency funding from the Commodity Credit Corporation. In February 2018, APHIS obtained $17.5 million in such emergency funding to support enhanced eradication efforts targetting spotted lanternfly in Pennsylvania. APHIS will continue to rely on Section 10007 funds to address this pest in other states to which it has apparently spread (Virginia, possibly Delaware, Maryland, and New Jersey).

Please ask your Congressional Representative and Senators to oppose these proposed cuts!

APHIS receives its annual appropriation through the Agriculture Appropriations bill. This legislation is written by the House and Senate Agriculture Appropriations subcommittees. Members of these subcommittees are listed below. These legislators are especially influential in determining funding for APHIS programs.

House:

Robert Aderholt, Alabama, Chairman
Kevin Yoder, Kansas
Tom Rooney, Florida
David Valadao, California
Andy Harris, Maryland
David Young, Iowa
Steven Palazzo, Mississippi
Sanford Bishop, Georgia, Ranking Member
Rosa DeLauro, Connecticut
Chellie Pingree, Maine
Mark Pocan, Wisconsin

Senate:

John Hoeven, North Dakota
Thad Cochran, Mississippi
Mitch McConnell, Kentucky
Susan Collins, Maine
Roy Blunt, Missouri
Jerry Moran, Kansas,
Marco Rubio, Florida
Jeff Merkley, Oregon
Diane Feinstein, California
Jon Tester, Montana
Tom Udall, New Mexico
Patrick Leahy, Vermont
Tammy Baldwin, Illinois

USDA Forest Service

The Administration has proposed damaging decreases in both research and management programs that target non-native insects and pathogens.

Research & Development

The research budget proposal contains numerous figures which don’t appear to add up. I have contacted USFS budget officials to learn how to understand these apparent discrepancies. To read the overall USFS budget, go here.

The budget proposes cutting overall research by 14.8% — from $306,216,000 to $260,800,000. According to the table on p. 30 of the budget justification, invasive species research is allocated $28,558,000. The text says this is 17% of the total Research budget – but my calculation is that it is 10.9%. The discrepancy apparently resulted from a failure to adjust to last-minute changes in funding amounts. The invasive species allocation is described as being a decrease of $3,217,000 from the FY18 figure. Despite these cuts, invasive species are described as one of six “strategic program areas”.

The Forest Service provides a table breaking out funding for work by the research stations on more than a dozen individual pest species or groups of species. The table listing this spending (on pp. 45-46) shows a total of $7,591,000 for FY18 and $6,271,000 for FY 19. The $22 million remaining in the “invasive species” program is apparently spent by staff at headquarters or possibly regional offices. I am trying to find out what this larger category of expenditures includes.

Furthermore, the $6.2 million total includes programs targetting several native species (western bark beetles, southern pine beetle), as well as subterranean termites and invasive plants. If one subtracts expenditures for those species, only $3,091,000 is allocated to non-native tree-killing insects and pathogens in FY18 and $3,252,000 for FY19. This is 1.2% of the overall research budget. Cuts for the individual species range from 19% to 21%.

Since 2010, total funding for research on the ten specified non-native insects and pathogens has fallen by more than 60% — from about $8 million to $3 million. The table listing expenditures on individual species cannot be complete; for example, it does not include efforts to breed pest-resistant elm and beech. Nor does it include recently detected pests, such as spotted lanternfly and polyphagous and Kuroshio shot hole borers – which I hope the Forest Service is studying.

The budget foresees a 42% cut in staff-years from FY18 to FY19 – from 1,469 to 855. USFS Research staffs have been falling for several years (illustrative graph is available in Chapter 6 of Fading Forests III here.) Supportive funds to cover costs of travel, fieldwork, student assistants, and grants to universities have also fallen precipitously, further impeding research efforts.

State & Private/ Forest Health Management

The Administration’s proposed budget for the USFS proposes a cut of 8.5% in the program that actually combats damaging pests. The cut to funding for pest-management projects on federal lands is 6.5% ($55,123,000 to $51,495,000). The cut to funding for work on state and private lands (the “cooperative lands” account) is 11% ($38,735,000 to $34,376,000). The budget assumes corresponding cuts to staff by 11% (341 staff-years).

The justification notes that, with this budget, the Service will be able to treat fewer acres, so the agency will “focus on the most pressing needs for forest restoration and reducing communities’ risk to wildfire”.

I consider the ostensible focus to be highly misguided. Even the budget justification concedes that pests and pathogens cause billions of dollars of damage each year and that pest-management methods are more effective when treatments are applied regardless of land ownership. Indeed, history shows that pests enter and first establish in urban and suburban areas that receive the imports that transport pests, like wood packaging or nursery stock. If the USFS fails to help counter pests at these introduction sites, it dooms itself to dealing with well-established invaders – at best an enormous and expensive effort, at worst, failure.

As noted earlier, the table on pp. 45-46 lists spending on individual pest species. The total given is $21,356,000 in FY18; the proposal cuts spending to $19,407,000 in FY19. As above, I subtract expenditures for native species (western bark beetles, southern pine beetle), subterranean termites, and invasive plants. The resulting subtotals are $12,874,000 for FY18 and $11,681,000 for FY19. As usual, the gypsy moth receives the bulk of the expenditures — 62% for both years. To meet the lower total mandated for FY19, spending is cut 8 – 9% for each non-native species listed.

In FY10, spending on the 11 named non-native insects and pathogens was $24 million. By FY18, it had fallen by nearly 50% — to $12.8 million. Pest species suffering the largest cuts are the Asian longhorned beetle (zeroed out), hemlock woolly adelgid (52% decrease), oak wilt (27% decrease), sudden oak death (18% decrease), and the combination of goldspotted oak borer, thousand cankers disease, and laurel wilt (15% decrease). The budget justification document does not provide sufficient information to allow me to judge the wisdom of the individual cuts.

It is troubling that the table makes no mention of other invaders – e.g., polyphagous & Kuroshio shot hole borers, spotted lanternfly, velvet longhorned beetle, winter moth (this last is mentioned in the narrative). The first four are relatively new pests with costs that could impose catastrophic damage if they are not countered by adequate programs.

Urban Forestry and International Programs

The budget proposes to eliminate funding for both urban forestry and international programs. I consider both programs important to invasive species management. The former strengthens forestry programs and public support for them in the very places where new pests are most likely to be introduced! The international program supports cooperation with foresters in foreign countries – the sources for potentially invasive insects and pathogens, as well as locales that can provide possible agents for biological control.

Please ask your Congressional Representative and Senators to oppose these proposed cuts!

The Forest Service receives its annual appropriation through the Interior Appropriations bill. This legislation is written by the House and Senate Interior Appropriations subcommittees. Members of these subcommittees are listed below. Again, please let them know of your concerns.

House:

Ken Calvert, California, Chairman
Mike Simpson, Idaho
Tom Cole, Oklahoma
David Joyce, Ohio
Chris Stewart, Utah, Vice Chair
Mark Amodei, Nevada
Evan Jenkins, West Virginia
Betty McCollum, Minnesota, Ranking Member
Chellie Pingree, Maine
Derek Kilmer, Washington
Marcy Kaptur, Ohio

Senate:

Lisa Murkowski, Alaska
Thad Cochran, Mississippi
Lamar Alexander, Tennessee
Roy Blunt, Missouri
John Hoeven, North Dakota
Mitch McConnell, Kentucky
Steve Daines, Montana
Shelly Moore Capito, West Virginia
Diane Feinstein, California
Patrick Leahy, Vermont
Jack Reed, Rhode Island
John Tester, Montana
Jeff Merkley, Oregon
Chris Van Hollen, Maryland

Posted by Faith Campbell

New study evaluates “candidate pool” from which invasive species might come

Campanula latifolia – one of the species detected as an “emerging” invasive species in the database relied upon by the authors of the study

The authors of a new study note that officials managing invasive species programs rely largely on knowledge of a species’ previous invasion history to predict its level of threat in the geographic area under their responsibility. This approach does not work with the many introduced species that have no history of a previous detected invasion. Hanno Seebens and 49 coauthors – including tree-pest experts Eckehard G. Brockerhoff, Marc Kenis, Andrew M. Liebhold, and Alain Roques — have sought to figure out how great a handicap that lack of data is. See “Global rise in emerging alien species results from increased accessibility of new source.” The study is available for $10 here. Figures, tables, and references are available without charge.

The study used a database of 45,984 first records of establishment of 16,019 species belonging to the following major taxonomic groups: vascular plants, mammals, birds, fishes, insects, crustaceans, mollusks, and other invertebrates.

Last year, many of the same scientists, relying on the same database, found that the rate of new introductions of alien species has risen rapidly since about 1800 – and shows no sign of slowing down. The adoption of national and international biosecurity measures during the 20th century have slowed introductions – but they are not sufficiently effective, especially regarding those plants and animals that are introduced primarily accidentally as stowaways on transport vectors or contaminants of commodities (e.g., algae, insects, crustaceans, mollusks and other invertebrates). The 2017 study found a strong correlation between these “accidental” alien species’ spread and the market value of goods imported into the region of interest. For that study, go here. I blogged about the findings on 1 March 2017 – here.

In the new 2018 article, the scientists found that even after many centuries of invasions the rate of emerging alien species is still high. Across all taxonomic groups, one out of four detections during 2000 – 2005 was of a species that had not been previously recorded anywhere as alien. Detections of “new” or “emerging” aliens is occurring at an even higher rate for some taxonomic groups. But new detections of insects fit the average – every fourth detection during 2000 – 2005 was of a species not previously recorded outside its native range.

The authors conclude that the continuing high proportion of “emerging” alien species is best explained by the interplay of 1) the incorporation into the pool of potential alien species of species native to regions formerly not accessible to traders; 2) increases in introduction rates due to higher import volumes; and 3) probably rising establishment rates as a consequence of land degradation that facilitates establishment in recipient regions. This process compensates for the decrease of new invaders from historically important source regions – from which potentially invasive species have presumably already taken advantage of pathways and been recorded as introduced somewhere.

emerald ash borer Agrilus planipennis – one of the species in the database of “emerging” invasive species

The number of insect species in the database candidate species pool is 20,611 species – an admittedly small fraction of all insects (for example, there are more than 350,000 beetle species worldwide). Twenty-four percent of these insect species have already been established somewhere outside their native ranges. However, the authors note that data gaps – which are larger for some taxonomic groups and geographic regions – mean that the number of actual “first” introductions is probably larger than records indicate, and consequently the estimated size of the candidate species pools may also be higher. Indeed, the paper does not attempt to estimate the actual size of the invasive species “pool” for insects.

The authors analyzed the importance of eight factors – temperature, relative humidity, import values, three land-use categories, number of botanical gardens, and human population size – in explaining the continued high number of “emerging” invaders detected in recent years. While these factors were explanatory for some taxonomic groups, they had a very low predictive value for insects.

For vascular plants, every third record of an introduction in 2000 – 2005 was of an “emerging” alien species. Interestingly, the number of botanical gardens in a country was a significant predictor for emerging alien vascular plants. However, as the authors of the article point out, reliance on this factor ignores the probable importance of other contributors such as the number of species planted in the receiving country; similarities between source and receiving environments; and introductions by acclimatization societies, European explorers or settlers, and plant hunters.

Acer ginnala –one of the species detected as an “emerging” invasive species in the database; photo by J. Weisenhorn, University of Minnesota extension

In any case, lots of previously undetected alien species are detected each year. In this database, 58% of the species had a single record; 86% of all species have no more than two first records in countries on the same continent. The large number of species with only one or two records led the authors to conclude that most species will not spread widely. I question that conclusion because species often require some time to spread to new locations – either local or distant. The authors do admit that they are unable to determine which species have a high potential for spread.

ash trees at the St. Louis arch – before arrival of emerald ash borer

The continued high rate of introduction of new species leads the authors to estimate that between 1% and 16% of all species on Earth – depending on the taxonomic group – qualify as potential invasive alien species. The authors did not attempt to estimate the true candidate pool or percentage of invasive species for insects. For vascular plants, the authors estimated the candidate pool at 47,000 species (out of a total of 368,000 species on Earth), or 13%.

Like its predecessor, this study’s importance arises from its broad perspective – covering the entire globe and a wide range of taxonomic groups. Its major conclusion that invasions will continue on a large scale serves as a warning to all stakeholders. These include officials charged with protecting agriculture and the broader economy, or the natural environment; conservationists; and those engaged in the economic activities that promote invasion.

However, the authors found that the data did not support more specific advice. First, as noted above, they were unable to determine which of the “emerging” invasive species in all taxonomic groups have a high potential to spread.

For those of us focused on invasive species that threaten native plants, data gaps limit the predictive value of the study the most. The database is too scant even to estimate the invasive species “pool” of potential insect pests. Plant pathogens are not included in the analysis.

Posted by Faith Campbell and Phyllis Windle