Bad News & Good News – current situation

  American beech; FT Campbell

 

I recently attended USDA’s annual Interagency Research Forum on Invasive Species in Annapolis, MD,  and have good and bad news to report about forest pests – mostly about insects but also a little on weeds.

Bad News

New pest: The European leaf-mining weevil is killing American beech in Nova Scotia. Jon Sweeney of Natural Resources Canada thinks it could spread throughout the tree species’ range. (I alerted you to another new pest of beech – beech leaf disease – at the beginning of December.  Beech is already hard-hit by beech bark disease.)

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]

Other bad news concerns the spread of already-established pests:

  1. Hemlock woolly adelgid has been detected in Nova Scotia – where it has probably been present for years.
  2. Emerald ash borer has been detected in Winnipeg, Manitoba – home to an estimated 350,000 ash trees. Winnipeg is 1,300 km (870 miles) from Saulte Ste. Marie, the closest Canadian outbreak. The closest U.S. outbreak is in Duluth, Minnesota — 378 miles.
  3. Despite strenuous efforts by Pennsylvania (supported, but not adequately, by APHIS), (see my blog from last February ), spotted lanternfly has been detected in Delaware, New York, and Virginia. A map showing locations of apple orchards in the Winchester, Virginia area is available here.
  4. There is continued lack of clarity about biology and impact of velvet longhorned beetle (see my blog from last February.) The Utah population appears to be growing. APHIS is funding efforts to develop trapping tools to monitor the species.
  5. Alerted at the Forum, I investigated a disease on oak trees caused by the pathogen Diplodia corticola. Already recorded in Florida, California, Massachusetts and Maine, last year the disease was also detected in West Virginia. Forest pathologists Danielle Martin and Matt Kasson don’t expect this disease to cause widespread mortality. However, they do expect it to weaken oaks and increase their vulnerability to other threats.

spread of laurel wilt disease

Laurel wilt disease is one of the worst of the established non-native pests. Two speakers at the Forum described its ecological impacts.

Dr. John Riggins of the University of Mississippi reported that 24 native herbivorous insects are highly dependent on plants vulnerable to the laurel wilt insect-pathogen complex. One of these, the Palamedes swallowtail butterfly (Papilio palamedes) has suffered a three-fold to seven-fold decline in populations at study sites after the death of redbay caused by laurel wilt.

Dr. Frank Koch of the USDA Forest Service expects that the disease will spread throughout most of the range of another host, sassafras. (See a map of the plant’s range). With the climate changing, the insect is unlikely to suffer winter cold mortality in the heart of the tree’s range in Kentucky, West Virginia, and Virginia.

Apparently many birds depend on spicebush, a shrub in the Lauraceae family, but there is no easily available data on any changes to its distribution or health.

 

Good News

Other speakers at the Forum provided encouraging information.

Scientists described progress on breeding American elm trees resistant to or tolerant of the introduced Dutch elm disease (DED). USFS scientists led by James Slavicek and Kathleen Knight are trying to improve the genetic diversity and form of disease-tolerant American elms and to develop strategies for restoring them to the forest.

More than 70 seedlings planted in an orchard are being inoculated with the DED pathogen to test the trees’ tolerance. The project continues to collect seeds or cuttings from apparently resistant or tolerant trees. If you are aware of a large surviving elm in a natural setting (not urban planting), please contact the program via its website.

The project is also experimenting with methods for restoring trees in the forest. In one such experiment, elms, sycamores, and pin oaks have been planted at sites in Ohio where openings had been created by the death of ash attacked by emerald ash borer. Survival of the elm seedlings has been promising.

 

Also, there is cause to be optimistic re:

  1. Walnut / thousand cankers disease

In the East, walnut trees appear to recover from thousand cankers disease. One factor, according to Matt Ginzel of Purdue University, is that the thousand canker disease fungus, Geosmithia morbida, is a weak annual canker that would not cause branch or tree mortality in the absence of mass attack by the walnut twig beetle. Another factor is the greater reliability of precipitation in the East. Dr. Ginzel is now studying whether mass attack by the beetle is sufficient – alone – to kill walnut trees.

 

  1. b) Sirex noctilio

In Ontario, Laurel Haavik, U.S. Forest Service, finds both low impacts (so far) and evidence of resistance in some pine trees.

 

Also, scientists are making progress in developing tools for detecting and combatting highly damaging pests.

  1. Richard Stouthammer of U.C. Riverside has detected an effective chemical attractant for use in monitoring polyphagous and Kuroshio shot hole borers.  He is testing other pheromones that could improve the attractant’s efficacy. He has also detected some chemicals that apparently repel the beetles. His colleague, pathologist Akiv Eskalen, is testing endophytes that attack the beetles’ Fusarium fungus.
  2. Several scientists are identifying improved techniques for surveillance trapping for wood-boring beetles. These include Jon Sweeney of Natural Resources Canada and Jeremy Allison of the Great Lakes Forestry Centre.

 

Progress has also been made in biocontrol programs targetting non-native forest pests.

  1. Winter moth

Joseph Elkington of the University of Massachusetts reports success following 12 years of releases of the Cyzenis moth – a classical biocontrol agent that co-evolved with the winter moth in Europe. The picture is complex since the moths are eaten by native species of insects and small mammals and parasitized by a native wasp. However, native predators didn’t control the winter moth when it first entered Massachusetts.

2) Emerald ash borer

Jian Duan of the Agriculture Research Service reported that biocontrol agents targeting the  are having an impact on beetle densities in Michigan, where several parasitoids were released in 2007 to 2010. The larval parasitoid Tetrasrticus planipennisi appears to be having the greatest impact. A survey of ash saplings at these sites in 2015 found that more than 70% lacked fresh EAB galleries. In other trees, larval density was very low – a level of attack that Duan thinks the trees can survive.

However, Tetrasrticus has a short ovipositor so it is unlikely to be able to reach EAB larvae in larger trees with thicker bark. Furthermore, most of the biocontrol agents were collected at about 40o North latitude. It is unclear whether they will be as successful in controlling EAB outbreaks farther South.

Consequently, Duan noted the need to expand the rearing and release of a second, larger braconid wasp Spathius galinae, continue exploration in the southern and western edges of the EAB native range for new parasitoids; and continue work to determine the role of the egg parasitoids.

A brochure describing the U.S. EAB biocontrol program is available here

Canada began its EAB biocontrol program in 2013, using parasitoids raised by USDA APHIS. While evaluating the efficacy of these releases, Canada is also testing whether biocontrol can protect street trees.

3) Hemlock woolly adelgid

Scientists have been searching for a suite of biocontrol agents to control HWA for 25 years. Scientists believe that they need two sets of agents – those that will feed on the adelgid during spring/summer and those that will feed on HWA during winter/spring.

The first agent, Sasajiscymnus tsugae, was released in large numbers beginning in 1995. It is easy to rear. However, there are questions regarding its establishment and impact.

Laricobius nigrinus – a winter/spring feeder from the Pacific Northwest – was released beginning in 2003. It is widely established, especially in warmer areas. A related beetle, L. osakensis, was discovered in a part of Japan where eastern North American populations of HWA originated. Releases started in 2012. Scientists are hopeful that this beetle will prove more effective than some of the other biocontrol agents.

Winter cold snaps in the Northeast have killed HWA. While HWA populations often rebound quickly, predatory insects might suffer longer-term mortality. This risk intensifies the importance of finding agents that attack HWA during the spring or summer. Two new agents – the silver flies Leucopis artenticollis and L. piniperda – may be able to fill this niche. Both are from the Pacific Northwest. Initial releases have established populations.

 

4) USDA scientists are at earlier stages of actively seeking and testing possible biocontrol agents targetting Asian longhorned beetle and spotted lanternfly.

 

5) Invasive Plant Management

A study in New York City shows that invasive plant removal can have lasting effects. Lea Johnson  of the University of Maryland studied vegetation dynamics in urban forest patches in New York City. Her publications are available here.

In the 1980s New York undertook large scale restoration of its parks, including removal of invasive plants – especially multiflora rose, porcelainberry (Ampelopsis) and oriental bittersweet (Celastris). The goal was to establish self-sustaining forest with regeneration of native species. In 2006, Dr. Johnson was asked to evaluate the parks’ vegetation. She compared restored sites and similar sites without restoration.

I find it promising that Dr. Johnson found persistent differences in forest structure and composition as much as 15 or 20 years after restoration was undertaken. Treated sites had significantly lower invasive species abundance, a more complex forest structure, and greater native tree recruitment.

Still, shade intolerant species were abundant on all sites. The native shade tolerant species that had been planted did not do as well because gaps in the canopy persist.

 

CONCLUSIONS

As always, the annual Interagency Research Forum on Invasive Species provides an excellent opportunity to get an overview of non-native pest threats to America’s forests and the ever-wider range of scientists’ efforts to combat those threats. Presenters from universities as well as USDA, Canadian, and state agencies describe the status of host tree and pest species, advance promising technologies for detection, monitoring and control, and – increasingly – strategies for predicting potential pests’ likely impact. The networking opportunities are unparalleled.

 

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.

 

You Might Be Surprised By Who is Authorized to Manage Wildlife on Federal Lands

mountain goats – introduced onto USFS-managed lands in the Columbia River Gorge at state initiative; in Utah, the state introduced mountain goats on lands adjacent to a USFS Research Natural Area

 

The journal Environmental Law has just published a 135-page article that debunks a common myth of wildlife management – a piece that the U.S. Forest Service tried to quash. The authors’ analysis could affect the introduction of potentially invasive non-native species – and the reintroduction of native ones – on federal lands.

Nie, M., C. Barns, J. Haber, J. Joly, K. Pitt & S. Zellmer. 2017. Fish and Wildlife Management on Federal Lands; debunking state supremacy. Environmental Law, Vol. 47, no. 4 (2017).

The article reviews the legal authority of federal and state governments to manage wildlife on federal lands.  The authors examined wildlife-related provisions within the National Park System, National Wildlife Refuge System, National Forest System, Bureau of Land Management, the special case of Alaska, the National Wilderness Preservation System, and the Endangered Species Act. They also reviewed cases where federal and state agencies came into conflict over wildlife management on federal lands.

Citing the U.S. Constitution, federal land laws, and relevant case law, the authors assert that federal agencies have an obligation, not just the discretion, to manage and conserve fish and wildlife on lands and waters under their management. They say that the often-cited statement that “the states manage wildlife and federal land agencies only manage wildlife habitat” is wrong from a legal standpoint. This is the myth that the article debunks.

Furthermore, the authors find that federal agencies frequently apply their powers in an inconsistent and sometimes even unlawful fashion. Due to political pressures, they may back down when confronted by states wanting to manage wildlife to achieve their own goals – even when the state’s goals conflict with the legally-mandated purposes of the federal land under question. Such goals might include ensuring maximum populations of “game” animals or introduction of species to new habitats – regardless of the potential impact on native plants and animals.

The authors note that federal land and wildlife laws provide ample opportunities for constructive intergovernmental cooperation in wildlife management. They call for truly mutual collaboration by federal, state, and tribal authorities in managing wildlife. However, such cooperation is blocked in part by states choosing to challenge the constitutional powers, federal land laws, and U.S. government supremacy. In addition, the authors contend, most states have not put together programs that address their own conservation obligations. These obligations are inherent in the widely recognized doctrine of wildlife being a public trust to be managed for the present and future benefit of the people, not the government or private individuals.

According to the website of the Forest Service Employees for Environmental Ethics,  posting of a draft of this article on the University of Montana website (where lead author Martin Nie teaches) led the U.S. Forest Service to pressure the university to withdraw the article. The university refused, and the Forest Service ended its contract with Nie and his research center.

The paper can be downloaded here. 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.

Posted by Faith Campbell

“Invasive Species Denialism” Increases Exponentially

 

Anthony Ricciardi and Rachael Ryan have analyzed 77 articles published from 1994 to 2016 in scholarly journals and the mainstream media that express some level of “invasive species denialism”. Denialist articles appearing in these publications have increased exponentially over the past three decades, most notably in the mainstream popular press – and they have the graph, fitted to a curve, to prove it.

The authors cite Diethelm and McKee (2009) in defining “science denialism” as “the use of rhetorical arguments to give the appearance of legitimate debate where there is none, with the ultimate goal of casting doubt on scientific consensus.” Similar strategies have appeared in disputes over the dangers of tobacco smoking and climate change.

Ricciardi and Ryan say that “[u]nlike normal scientific debates, which are evidence based, this discourse typically uses rhetorical arguments to disregard, misrepresent or reject evidence in attempt to cast doubt on the scientific consensus that species introductions pose significant risks to biological diversity and ecosystems….” In their view, the “denialist” articles assert an absence of damage from bioinvasion “despite peer-reviewed research that shows otherwise ….”  One example of evidence ignored by the contrarians are several analyses of the causes of endangerment or extinction of vertebrate species listed on the Red List maintained by the IUCN [as reported in my blog from May 2016 link]

Furthermore, these claims are almost always made in the absence of peer review – either in popular media or as opinion articles in scholarly journals. Many of the writers are social scientists and philosophers, not natural scientists. Only five of the 77 articles, or 6%, were published in natural science journals.

Ricciardi and Ryan say that unlike genuine scientific debate, “denialists” reject scientific evidence while repeating claims that have already been refuted in the scientific arena. Often, “contrarians” link invasion biology to xenophobia and latent racism, or otherwise impugn the motives of those engaged in the invasion biology field.

Ricciardi and Ryan consider possible reasons for the rise in “denialist” articles. Possible reasons include anti-regulatory ideologies, distrust of scientific institutions, conflicting values and perceptions of nature, even individuals’ desire for attention. They note that despite the absence of a true scientific controversy, the “denialists’” assertions gain credibility because science reporters think they need to present “both sides” of the argument.

Unlike the situation in the contrived controversies over climate change and risks from tobacco, we at CISP have not found a powerful industry backing the contrarians.

Ricciardi and Ryan express concern that the growing number of articles rejecting decades of research on invasive species might undermine policy initiatives at a time when invasion biology’s relevance to biosecurity, conservation, and ecosystem management is increasing. Gaining public support is critical to the success of such policies.

This concern is especially well-founded given that the authors’ results underestimate the extent of invasive species denialism. That is, they omitted from their analysis articles from internet blogs – known to be major platforms for promoting “science denialisms” – and websites that specifically attack invasion biology.

While Ricciardi and Ryan published this as a “note,” it is packed with information, e.g., references on science denialism, in general; and, in supplementary information, a table citing the 77 denialist articles.

 

SOURCE

INVASION NOTE. Ricciardi, A. & R. Ryan The exponential growth of invasive species denialism. Biological Invasions. Published online 12 September 2017

 

New Disease that Attacks Beech is Spreading

beech leaf disease symptoms;  photo by John Pogacnik, Lake Metroparks

In 2012, Ohio authorities detected a new disease attacking American beech (Fagus grandifolia) in northeast Ohio. The disease has spread to several counties in northeast Ohio and neighboring areas of Pennsylvania, New York, and Ontario.

Counties currently reporting beech leaf disease; Cleveland Plain Dealer relying on data from Ohio Department of Natural Resources

Currently, no cause has been determined – despite efforts by the USDA Forest service, Ohio Division of Forestry, Ohio Department of Agriculture, Holden Arboretum, and Ohio State University.

Early symptoms are dark striping on the leaves – best seen by looking upward into the backlit canopy. The striping is formed by a darkening and thickening of leaf tissue between leaf veins. Later, lighter, chlorotic striping may also occur. Both fully mature and very young “emerging” leaves show symptoms. Eventually the affected foliage withers, dries, and yellows. Bud and leaf production is also affected. However, there is little premature leaf loss.

All ages and sizes of beech are affected. Sapling and pole-sized trees die within about three years after symptoms are observed. In areas where the disease is established, the proportion of American beech affected nears 100%.

Disease incidence does not appear to be influenced by slope, aspect, or soil conditions. Also, while a wide variety of insects and pathogens is associated with symptomatic trees, these appear to be separate from and unrelated to beech leaf disease.

The disease might also affect European and Asian beech.

Given the range and ecological importance of American beech – a species already under threat in from beech bark disease – scientists seek to form a collaborative group that would efficiently address research issues related to the cause of this malady and management implications for the species.

Beech trees in the Northeast, Appalachians, and even Michigan are already under threat from beech bark disease, described here .

Workshop to Coordinate Research and Management

A workshop will take place May 2-3, 2018 at Cleveland Metroparks Watershed Stewardship Center, 2277 West Ridgewood Drive, Parma, OH 44134

https://clevelandmetroparks.com/parks/visit/parks/west-creek-reservation/watershed-stewardship-center-at-west-creek

Presentations on the first day of the meeting would seek to

  1. Prioritize next steps and coordinate efforts.
  2. Increase communication and coordination among land managers and researchers.
  3. Inform resource allocation and leverage funding sources for maximum effectiveness.
  4. Set up 5-year plan – Research, Survey, Diagnostics, etc.

The second day would include a field trip to view the disease.

Contact one of the following if you are interested in giving a presentation on the ecological importance of beech; or the history, etiology, surveys, or epidemiology of beech leaf disease.

healthy beech in Virginia; F.T. Campbell

SOURCES

http://portal.treebuzz.com/beech-tree-leaf-disease-no-known-cause-1036

John Pogacnik, Biologist, Lake Metroparks & Tom Macy, Forest Health Program Administrator, Ohio Department of Natural Resources Division of Forestry. Forest Health Pest Alert Beech Leaf Disease July 2016

 

What Is USDA Waiting For?

 

As I wrote in my blog in October, the Department of Homeland Security Bureau of Customs and Border Protection (CBP) has reversed a previous policy and now has the option to impose a financial penalty on importers when any of their shipments does not comply with the international standard for wood packaging (International Standard for Phytosanitary Measure Number 15 – or ISPM#15). The penalties are assessed under Custom’s authority per Title 19 United States Code (USC) § 1595a(b) or 19 USC § 1592.

The Department of Agriculture has its own legal authority to penalize shippers whose wood packaging violates regulations implementing ISPM#15.  However, USDA not taken the equivalent step of using its own authority to crack down on violators. Why not?

APHIS’ legal authority stems from the Plant Protection Act of 2000 [7 U.S.C. §7701, et seq. (2000)] (The text is posted here)

This law provides broad authority to APHIS to penalize non-compliant importers, using both civil and criminal penalties. Under Section 7734 (b):

“Any person that violates this chapter … may, after notice and opportunity for a hearing on the record, be assessed a civil penalty by the Secretary…” The penalty can vary from $50,000 to $1 million, depending on whether the importer is an individual or a corporation; the number of violations adjudicated in the proceeding; the gravity of the violation; and the importer’s ability to pay. Civil penalties can be assessed regardless of whether the violation was intentional (in the language of the statute, “willful”).

Under Section 7734(a), the Department may seek criminal penalties in cases when the importer “knowingly” violated the law and its implementing regulations. Criminal penalties include both fines and imprisonment. To apply a criminal penalty, USDA must convict the importer in a trial – prove the violation beyond a reasonable doubt.

 

It is puzzling that USDA has not acted on this authority.

As we all know, the biological diversity of America’s forests’ is severely threatened by wood-borers that can enter the country in wood packaging. Tree mortality caused by non-native pests has been estimated to cost municipalities $1.7 billion per year (Aukema et al. 2011). For discussions of introduced pests’ impacts, see the sources listed at the end of this blog.

Nearly 12 years after APHIS adopted regulations implementing the formal International Standard for wood packaging, significant numbers of shipments that do not comply with the regulations continue to arrive. In the fiscal year that ended on September 30, Customs detected 2,000 shipments in which the wood packaging did not bear the mark certifying that the wood had been treated in accordance with ISPM#15. In nearly 900 additional shipments, CBP detected damaging pests in the wood packaging. (For more detail on this issue, see my blog from last February.) link. So, the need to improve compliance is manifest. Imposing a financial penalty strikes me as an available and useful strategy to achieve that improvement.

The new CBP policy is a much-needed step. Now USDA should reinforce that action by implementing its own enforcement powers. The USDA’s Office of General Counsel and APHIS should be asked what is preventing implementation and what can be done to move this forward. Effective action to interdict forest pests requires strong enforcement by both CBP and USDA. Right now, it looks like the Department of Homeland Security cares about U.S. forests more than the Department of Agriculture.

 

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)

Background on forest pest damages:

Campbell and Schlarbaum, Fading Forest reports 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  Recommendations available at www.caryinstitute.org/tree-smart-trade

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.

 

Invasive Plants in the Forest – focus on the Northeast

control of multiflora rose

Nancy Dagli, USDI National Park Service, Bugwood.org

 

Nearly two years ago I posted a blog based on a study by Christopher Oswalt and colleagues (2016; source/link provided at end of blog) using data from the national Forest Inventory and Analysis (FIA) program of the United States Forest Service to determine what proportion of American forests are invaded by non-native plants. Nationwide, 39% of forested plots sampled contained at least one invasive species. Eastern forests are second in the density of invasive plants to Hawai`i, with 46% of plots invaded by at least one plant species.

FIA sampling plots are randomly located across the country. Plots are inventoried once every 5–7 years in the eastern U.S. and once every 10 years in the western U.S. The program inventories only plots that are at least 10% stocked by trees. Phase 2 (P2) plots represent approximately 6,000 acres; Phase 3 (P3) plots represent about 96,000 acres, except in some states and National Forests where there is a regional intensification of plots. Invasive plant species are measured on a subset of the field plots – on the P2 invasive plots, invasive plants of interest are recorded; on the P3 plots, all plant species (invasive, exotic, and native) are recorded.

The US Forest Service Northern Region (Region 9) has issued a report providing details for 50 invasive plant species on plots in the 24 states of the Region. (These states reach from Maine to the Dakotas, south to Kansas, then across to Delaware.) For this report, in states where both P2 invasive and P3 data were collected, the invasives data from the P3 plots were folded into the P2 invasive plots. When there were no P2 invasive plots for a particular inventory or species, the IPS data were calculated solely from P3 plots. In addition, the taxa reported varied over time and in some cases from state to state. Finally, the inventories took place over a period of years; the most recent inventories included in the report date from 2010. Presumably, the extent and intensity of plant invasions have increased in the intervening seven years. [The report is posted here.

Given the variety of plots inventoried, changes in taxa recorded, and time lag, the report cannot provide an up-to-date and detailed picture of any one site.  However, it does allow us to get an overall picture that is more detailed than the nation-wide summary provided by Oswalt et al. 2016 and reported in Faith’s blog from spring 2016.

The report contains a wealth of data on the 50 individual species – a page for each, providing background, characteristics, distribution, monitoring data, and regulatory status in the various states. Also, there are 10 pages of summary tables. Since FIA inventories are conducted on the schedule of five to seven years, future reports based on these “[r]epeated measurements will help determine factors … associated with the presence of these species” and that the data can help “educate individuals of potential risk species”.

 

Our Interpretation

It is unfortunate that the USFS Southern Region has not prepared a similar report so that we could understand the extent of invasion by the individual taxa across the entire eastern deciduous forest. This is especially unfortunate because the Northern Region report found that the number of invasive plant species on a plot is higher in the southeastern portion of the Region (i.e., the states of West Virginia, Maryland, and Delaware). The arbitrary boundary between the Northern and Southern regions prevent our getting a true regional picture for the Mid-Atlantic states. The Oswalt et al. 2016 summary does allow some comparisons.

Still … we found it striking that seven of the 15 invasive plant species ranked highest in terms of proportion of plots invaded are shrub or vine species that were deliberately planted for improving wildlife habitat, horticulture, or other purposes.

 

Detailed Findings

The report does not state the proportion of all survey plots invaded by at least one invasive plant species for the region as a whole. Table 3 does report the proportion of plots in specific states. This varies from a high of 93% of plots in Ohio to a low of about 11% in Minnesota and New Hampshire. Several other Midwestern states also experience high levels of invasion: Iowa 81%, Indiana 79%, Illinois 72%, and Missouri 46%. Plots in Mid-Atlantic states and southern New England also are heavily invaded: West Virginia 79%, Maryland 65%, Pennsylvania 61%, Connecticut 54%, Rhode Island 51%, New York 49%, New Jersey 48%, Delaware 47%, Massachusetts 44%. In general, states in the far north have lower rates of invasion, like Minnesota and New Hampshire (above): Vermont 18%, South Dakota 15%, Michigan 14%, Maine 12%. However, North Dakota, at 29%, and Wisconsin, at 28%, differ from this generalization.

The most frequently recorded invasive plant is multiflora rose. According to the report, it is present in 39 states and five Canadian provinces. Across the region, multiflora rose is present on 16.6% of surveyed plots. It is the most common invasive plant in 10 of the 24 states of the region. It is almost ubiquitous in some states; in Ohio 85% of the plots were invaded. Oswalt reports that “roses” were the third most common invasive plants in the USFS Southern Region.

The third most frequently recorded invasive plant species is garlic mustard. It is reported to be present in 36 states and five Canadian provinces. Across the region, garlic mustard is present on 4.5% of the surveyed plots. Several states report high levels of infestation. In Ohio, garlic mustard is present on 30% of the plots; in Maryland, on 27% of the plots; in Pennsylvania, on 22% of the plots; in New Jersey, on 20%.

The fourth most frequently recorded invasive is common or European buckthorn. It is reported to be present in 34 states and eight Canadian provinces. Buckthorn is present on 4.4% of survey plots across the northeastern region – about a quarter of the plots on which multiflora rose is found. The highest proportion is in New York, where the invasive shrub is found on 16.8% of the plots.

Several bush honeysuckles rank high in the survey. Because of their close relationship and similar ecological impacts, we will discuss them together. Morrow’s honeysuckle is the fifth most commonly detected invasive plant species. This species is found on 3.8% of plots across the region. Amur honeysuckle ranks tenth; it is found on 3.1% of plots. Tatarian honeysuckle ranks sixteenth; it occurs on 1.5% of plots across the region. The hybrid showy fly, or Bell’s, honeysuckle ranks eighteenth; it occurs on 1.1% of plots. The data do not indicate whether there is much overlap in the plots invaded by the various species, so we cannot determine an overall invasion extent for bush honeysuckles – although clearly they occupy a significant proportion of the forest of the region. If there is almost no overlap, bush honeysuckles occupy 9.5% of all surveyed plots – second only to multiflora ros. During the first year of the survey, bush honeysuckles were recorded by genus – but only in four Midwestern states. In that survey, the genus was found on 6.5% of the plots surveyed.

The sixth most frequently recorded plant species is also an Asian honeysuckle – the vine Japanese honeysuckle, which is found on 3.6% of survey plots across the region. Oswalt et al. 2016 report that Japanese honeysuckle is the most common invasive plants in forests in the Southern region.

The second and seventh most frequently recorded plant species are native to parts of the region surveyed – although they have spread. These are black locust and reed canarygrass. We are confused as to how many of the reported plots actually represent invasions by these species since several states with high proportions of plots bearing black locust, for example, are in or next to the Appalachian mountains and the Ozarks, where the species is native.

The eighth and eleventh most frequently recorded invasive plant species are thistles — Canada thistle is eighth, bull thistle is eleventh. Both are found in more than 40 states and all 10 of the Canadian provinces. Each is present on approximately three percent of the plots, with concentrations in the upper Midwest.

The ninth and twelfth highest ranking invasive plant species in the region are additional shrubs which were deliberately planted for various purposes. Autumn olive ranks ninth; it occurs on approximately three percent of plots across the region. It is particularly dense in West Virginia, where it occurs on one fifth of all plots surveyed. Japanese barberry ranks 12th. It occurs on 2.4% of the plots across the region. In Connecticut, barberry is found on one-third of the plots.

The thirteenth most common species is common burdock – found on 2.2% of the plots. Again, the highest densities are found on forest plots in the upper Midwest along the edge of the prairie.

The fourteenth most commonly reported species is Nepalese browntop or Japanese stiltgrass. Stiltgrass has spread without much artificial assistance. Although stiltgrass is more common in the Southeast (outside the study region), it still occupies 2.1% of surveyed plots in the Northern region. Owald et al. 2016 report that stiltgrass is the fifth most common invasive plant in the Southern region.

Additional Studies Needed

  • The USFS Northern and Southern regions should coordinate their reports so that at least some use compatible methods and combine their findings so can see the picture for the entire Eastern forest.
  • USFS scientists should collaborate with other programs that map invasive plants – e.g., EDDMapS, the National Park Service, and Invasive Plant Councils – in both selection of species to target and developing an overall picture. As noted in Faith’s earlier blog, the Mid-Atlantic Invasive Plant Council has a list of 285 invasive plants in the region. Does the subset of 50 species selected for the FIA inventories provide an accurate picture of plant invasions in this sub-region?
  • Scientists should cooperate to evaluate the relative importance of propagule pressure v. forest fragmentation as factors in facilitating invasions. Their relative roles probably vary by species, receiving forest, etc.
  • We welcome the attention to invasions of interior forests – a topic previously neglected. Nevertheless, forest “edges” are also important ecologically – and – based on what we see in the Mid-Atlantic region – are even more heavily invaded. What impact does a wall of vines have on wildlife and plant species that evolved to live in area of greater light and temperature variation of trees, shrubs, herbaceous species that made up the edge before invasion?

Actions to Counter Plant Invasions

  • Those who sell plants for any use – ornamental horticulture, ground cover, livestock forage, soil amelioration, wildlife habitat management, biofuels – should commit to avoiding species that are known or suspected to be invasive in the region.
  • Voluntary efforts to limit sales of invasive plants have fallen by the wayside. The various Invasive Plant Councils should work with industry groups and others to renew this effort. Also, the Councils should propose a joint list of additional plants for APHIS regulation under NAPPRA (see below).
  • Those who buy plants for these various uses should make a similar commitment – especially large, institutional buyers like state highway departments.
  • Concerned citizens should lobby their state governments and the Congress to fund “noxious weed” programs and to ensure that these programs include plant species that threaten natural areas, not just weeds of agriculture.
  • Concerned citizens should lobby the Congress to increase funding for federal agencies’ invasive plant control programs, especially those addressing natural areas, and especially in Hawai’i and the eastern United States. Also, 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.

In June 2017, APHIS finalized its May 2013 proposal to restrict importation of 22 potentially invasive plant species – as provide by its NAPPRA program. (For a description of this program and the recent action, visit Faith’s blog here. APHIS should be empowered to use this program more aggressively to list additional plant taxa that appear likely to be invasive.

Source

Christopher M. Oswalt, Songlin Fei, Qinfeng Guo, Basil V. Iannone III, Sonja N. Oswalt, Bryan C. Pijanowski, Kevin M. Potter 2016. A subcontinental view of forest plant invasions. NeoBiota. 24: 49-54 http://www.srs.fs.usda.gov/pubs/48489

posted by Faith Campbell & guest Jil Swearingen

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.

 

New Woodborer Detected – Importance of Surveillance By-Catch

 

Agrilus smaragdifrons – photo by Ryan Rieder, New Jersey Department of Agriculture

 

At least 11 non-native metallic wood-boring beetles in the genus Agrilus  have been introduced to either the United States or Canada – or both. The most recent detection is Agrilus smaragdifrons Ganglbauer, which feeds on the invasive plant tree of heaven (Ailanthus altissima). This information comes largely from an important new paper by noted entomologist E. Richard Hoebeke at the University of Georgia and others (see the reference Hoebeke et al. 2017 at the end of this blog).

 

Two more Agrilus species that are native to Mexico and – in one case, also Arizona – have been introduced to separate parts of the U.S. and are killing naïve hosts there. These are A. prionus (which attacks soapberry trees in Texas) and A. auroguttatus (the goldspotted oak borer, which attacks several oak trees in California). Both species are described here

 

The genus Agrilus is considered to be the largest genus of the entire Animal Kingdom; it has over 3,000 valid species (Hoebeke et al. 2017).

 

Most of the Agrilus introduced to North America do not attack trees. Several attack crops such as grapes, currants and gooseberries, and rasberries (Hoebeke et al. 2017; (Jendek and Grebennikov 2009; reference at the end of the blog). Others attack horticultural plants including roses, wisteria, and mimosa (Jendek and Grebennikov 2009).

 

Still others attack plants that are invasive, such as honeysuckles (Lonicera spp). One, A. hyperici Creutzer, was deliberately introduced as a biocontrol agent targeting St. John’s wort (Hypericum perforatum L.) (Jendek and Grebennikov 2009).

 

However, Agrilus sulcicollis attacks oaks, beech, chestnut and other trees in the Fagaceae family in its native Europe. The beetle was detected in Ontario in 2006 (Jendek and Grebennikov 2009).

 

The most recently detected East Asian “jewel” beetle, Agrilus smaragdifrons, was discovered by analysis of Agrilus species caught in surveillance programs targeting other species – usually emerald ash borer (EAB) (A. planipennis). The beetle was first identified in traps deployed by the New Jersey Department of Agriculture. Unlike in many trapping programs, New Jersey screened the trap catches for all beetles in the family Buprestidae (which includes EAB). In 2015, two samples from separate trapping sites in the state contained a distinct but unrecognized species. These were identified by Dr. Hoebeke as the East Asian A. smaragdifrons (Hoebeke et al. 2017).

 

Alerted to the new species, scientists conferred and found additional detections of the species. An EAB biosurveillance program in New England utilizing the native ground-nesting wasp Cerceris fumipennis also detected the A. smaragdifrons in at least one location in central Connecticut in 2015. (The wasps capture beetles in the Buprestid family to feed to their young. By observing which species of beetles are brought to their nests by the wasps, scientists can learn which species are present in an area.)

 

Pennsylvania has collected A. smaragdifrons in surveillance programs targeting either EAB or spotted lantern fly (Lycorma delicatula (White))(Hoebeke et al. 2017).

locations where A. smaragdifrons has been detected; map from Hoebeke et al. 2017

It turned out that A. smaragdifrons has been in the U.S. for several years. One scientist photographed the beetle – without knowing what it was – in 2011 in New Jersey and posted the image at BugGuide (http://bugguide.net/node/view/1139674/bgimage ; accessed by Hoebeke and colleagues on 1 May 2017).

 

Recent field observations in China and the U.S. have observed both adults and larvae feeding on tree of heaven. In Beijing, many Ailanthus trees in gardens or along roadsides have succumbed to attack by this wood-borer. Other tree species on the grounds of Beijing Forestry University have not been attacked by A. smaragdifrons (Hoebeke et al. 2017). Still, no proper host-specificity test has yet been conducted on the beetle.

 

Of course, Ailanthus is widespread across North America, from southern Canada to Florida, and even along river courses in the arid Southwest. According to the USDA Forest Service (see the third on-line reference at the end of the blog), Ailanthus is known to be present in 42 states. It is most abundant in the Mid-Atlantic and Northeastern states. For example, 18% of the forest plots inventoried by the USDA Forest Service Forest Inventory Analysis program in West Virginia had Ailanthus present. Efforts are under way to try to find biocontrol agents (Hoebeke et al. 2017).

 

 

Importance of analyzing by-catch in insect detection surveys.

 

While most managers of pest surveys ignore the non-target species caught in their traps (“by-catch”), this detection shows that examining the by-catch can sometimes result in discovering previously unknown species. (Other examples of such detections include the pine pest Sirex noctilio in New York in 2004 and the oak-feeding Agrilus sulcicollis in Ontario and later Michigan.

 

Hoebeke and his colleagues strongly recommend that scientists pay attention to non-target insects captured in their surveys, especially those insects that show up in any abundance for the first time.

 

SOURCES

 

Hoebeke, E.R., E. Jendek, J.E. Zablotny, R. Rieder, R. Yoo, V.V. Grebennikov and L. Ren. 2017. First North American Records of the East Asian Metallic Wood-Boring Beetle Agrilus smaragdifrons Ganglbauer (Coleoptera: Buprestidae: Agrilinae), a Specialist on Tree of Heaven (Ailanthus altissima, Simaroubaceae) Proceedings of the Entomological Society of Washington, 119(3):408-422.

 

This article demonstrates how to distinguish the Ailanthus beetle from other Agrilus species.

 

Jendek, E. and V.V. Grebennikov. 2009. Agrilus sulcicollis (Coleoptera: Buprestidae), a new alien species in North America. Canadian Entomologist 141: 236–245.

Maryland has declared A. smaragdifrons its “invasive species of the month” for December 2017. Visit http://mdinvasivesp.org/invader_of_the_month.html

Information about Ailanthus as an invasive plant is available at

https://www.invasivespeciesinfo.gov/plants/treeheaven.shtml ; https://www.nps.gov/plants/alien/pubs/midatlantic/midatlantic.pdf

https://www.nrs.fs.fed.us/pubs/43136

New “Plant Pest” Boss Soon to Take Office

Gregory Ibach

 

Gregory Ibach has been appointed USDA Under Secretary of Agriculture for Marketing and Regulatory Programs. He will supervise APHIS.

Mr. Ibach has strong ties to mainstream agriculture. A fourth-generation farmer (cow-calf and rowcrops), he has served as Nebraska’s Commissioner – or Deputy – of Agriculture under three governors – since 1999. His academic background is animal science and agricultural economics.

Mr. Ibach’s nomination was supported by 60 organizations, including the Farm Bureau, National Cattlemen’s Beef Association, and National Corn Growers.

The Senate Committee on Agriculture, Nutrition & Forestry held a very friendly hearing on Mr. Ibach’s appointment on October 5, 2017 2017 (video posted at the Committee website)  During the hearing – which was shortened by the need to attend to other Senate business – Senators’ attention focused on the farm conservation programs managed by the other nominee at the hearing (William Northey, nominee for Undersecretary for Farm and Foreign Agricultural Services). In response to several questions about marketing programs, Mr. Ibach said he needed to learn more about an issue.

In his formal testimony, Mr. Ibach noted the breadth of responsibilities under the jurisdiction of the Under Secretary for Marketing and Regulatory Programs and promised to find a balance between the two duties: representing and promoting the interests of farmers and ranchers; and overseeing some of the entities that regulate them. (Written testimony posted on Committee website — link above.)

“If confirmed, I will help the Secretary achieve his goals through ensuring sensible and effective regulations, responding to our customers in a timely and straight forward manner, focusing on plant and animal health program effectiveness, and fostering safe innovation that is farmer, consumer and environmentally sound.”

I summarize key points of the hearing below.

Committee Chairman Pat Roberts (R-KS) noted that foreign animal disease threats – such as avian influenza – have threatened agricultural production and asked what Mr. Ibach’s priorities would be for safeguarding animal health. Mr. Ibach said he takes very seriously APHIS’ responsibilities to keep diseases and pests out of the country and to control those that enter. He promised to learn about every program.

Ranking Democrat Debbie Stabenow (D-MI) asked Mr. Ibach about budgetary pressures. He responded by saying he would commit to doing the best job possible with available funds and to pursue efficiencies.

Amy Klobuchar (D-MN) was also concerned about disease threats to Minnesota’s large-scale turkey and hog producers.

John Hoeven (R-ND) pressed Mr. Ibach to find a solution to blackbirds as a threat to agriculture. Mr. Ibach said they are a problem in Nebraska, too. He promised to seek a “balanced” approach that preserved wildlife “when appropriate” while protecting farmers from destruction and disease threats.

Senator Leahy (D-VT) submitted questions pertinent to our concerns about tree-killing pests. Noting that Mr. Ibach had spoken about the pest threat to farmers, ranchers, and producers but had made no mention of the forest pests, Senator Leahy asked:

  • What familiarity do you have with APHIS’ work to keep out invasive forests pests that threaten our nation’s forests and the rural jobs and economy those forests support?

Mr. Ibach replied: I am familiar with the work that APHIS does in partnership with states to keep out and eradicate forest pests. In fact, in Nebraska, we have been working closely with APHIS prior to and since Emerald Ash Borer was found in the state for the first-time last year. These pests can absolutely devastate our forests, and if confirmed, I would work to make sure that APHIS’ pest programs, including those to protect the green mountains of Vermont, are effective.

  • Can you tell me how many wood and tree pests APHIS inspectors find every year, which theoretically should not have made it to our shores if importers were using the best available processes and phytosanitary practices to keep American agriculture and natural resources safe? And do you commit to looking into this issue and finding ways to safeguard both American agriculture and our natural resources?

Mr. Ibach replied: I do not have that data, but commit to learning more and working every day to protect American agriculture and natural resources if confirmed.

Senator Roberts said that the Committee would act soon to approve the nominations of Gregory Ibach and William Northey.

 

The Under Secretary for Marketing and Regulatory Programs sets the tone for APHIS’ efforts.  This person can prompt aggressive protection efforts … or block such efforts by opposition or indifference.  Let’s hope that Mr. Ibach plays the former role!

 

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.

 

Penalties for Importers Who Violate Wood Packaging Rules!

CBP inspection of wood packaging; CBP photo

On September 25, the DHS Bureau of Customs and Border Protection (CBP) announced that beginning on November 1, the agency would no longer eschew penalizing importers of non-compliant wood packaging until that importer had accumulated five such interceptions in the course of a year.

Beginning November 1, “responsible parties with a documented WPM violation may be issued a penalty under Title 19 United States Code (USC) § 1595a(b) or under 19 USC § 1592.”

As readers of this blog might remember, I have frequently fulminated against the “five strikes” policy.  The United States began full implementation of the international standard governing treatment of wood packaging (ISPM#15) 11 and ½ years ago. The U.S. and Canada began requiring China to treat its wood packaging nearly 18 years ago. Nevertheless, numerous shipments containing wood packaging that does not comply with the regulations continue to arrive at our borders – and to bring pests. As of February, only about 30 import shipments (out of nearly 21,000 shipments found to be in violation of ISPM#15 requirements) have received a financial penalty.

shipments of stone or tile are frequently supported by non-compliant wood packaging; photo (c) the Queen by right of Canada (CFIA)

In a blog I posted in February I described the continuing detections of pests in wood packaging. In summary, during Fiscal Years 2010 through 2016, CBP detected nearly 5,000 shipments of wood packaging that harbored a pest in a regulated taxonomic group. The APHIS interception database for the period FYs 2011 – 2016 contained 2,547 records for insect detections on wood packaging. The insects belonged to more than 20 families. A quarter were in the Cerambycid family; 11% were Buprestids. In a study of insect larvae removed from incoming wood packaging from the period April 2012 through August 2016, APHIS scientists evaluated 1,068 insects from 786 separate interceptions of non-compliant wood packaging. The wood packaging in all three datasets came from dozens of countries.

 

(Remember, the U.S. and Canada do not apply ISPM#15 to wood packaging moving between the two countries. Neither country inspects wood packaging from the other country at even the low rate of inspection applied to wood packaging coming from other countries – so we don’t know how many quarantine pests are moving in this high-volume trade.)

 

The Bureau of Customs’ action has partially fulfilled one of two recommendations that I made in the February blog. I applaud CBP’s action. However, neither CBP or APHIS has yet prohibited importers with records of repeat violations from using wood packaging – my second recommendation.

 

Note that the CBP decision applies Customs regulations; USDA has apparently not changed its policy of allowing importers to accumulate five (detected) violations in a calendar year before applying the civil penalties provided by the Plant Protection Act.  Why?

 

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.

Posted by Faith Campbell

Biological Control Approved for Invasive Black and Pale Swallow-wort!

black swallow-wort; photo by Leslie J. Mehrhoff, University of Connecticut

Help is on the way!

With funding support through the Northeast IPM Partnership, University of Rhode Island entomologist Richard Casagrande has been leading a team to find biological control agents for two invasive plant species. The target species, black swallow-wort (Vincetoxicum nigrum) and pale swallow-wort (Vincetoxicum rossicum), are native to Europe and members of the milkweed family Apocynaceae (previously Asclepiadaceae). In the U.S., their vigorous growth overtakes and smothers small trees, shrubs and other native plants and threatens the survival of the monarch butterfly whose larvae rely on milkweed for their development. They are currently found in the northeastern and mid-Atlantic states but could spread much farther.

(See Faith’s earlier blog about USDA speeding up approvals of biocontrols for invasive plants here.

U.S. native swallow-wort species belong to the genus Cynanchum and include a dozen or so rare and endangered plant species. It was essential to consider these native species in the investigations. Feeding tests would need to show definitively that the potential biocontrol species would not attack native swallow-worts or other native members of the milkweed family. And, Jennifer Dacey, Casagrande’s graduate student, wanted to find out how well the exotic swallow-worts might provide for monarch butterflies. The results were alarming.  All of the monarch larvae died when hatching on black swallow-wort.  “They stopped eating after a single bite,” says Casagrande.

pale swallow-wort; photo by Leslie J. Mehrhoff, University of Connecticut

Why biological control?

Small infestations of invasive swallow-wort, seedlings and young plants can be pulled up by hand, mature plants can be dug up, and frequent mowing can suppress populations in fields. However, most infestations are too extensive to control by hand. Systemic herbicides – those that are carried through the plant to the roots — can be used to control large infestations, using foliar sprays. Several years of treatment will likely be needed due to the persistence of swallow-wort seeds. These efforts can be part of an overall Integrated Pest Management strategy but the best long-range solution is biological control. Biocontrol relies on finding herbivores that have coevolved to feed on specific invasive plants in their native range that will not have a significant impact on non-target species. Graduate student Aaron Weed worked with Swiss scientists to identify a handful of specialist plant herbivores, mainly beetles and moths that evolved with black swallow-wort and pale swallow-wort in their native ranges in Europe and were highly unlikely to feed on other plant species.

Approval process.

All biological control agents must be approved for release by the U.S. Department of Agriculture, Animal and Plant Health Inspection Service (APHIS). APHIS sets up a Technical Advisory Group, or “TAG”, to review the research on feeding tests conducted by the researchers, called “no-choice” tests.  Potential biocontrol agents are tested for feeding on an extensive selection of native plant species and their relatives to ensure the agents are specific to the target species and won’t pose a threat to agriculture or to rare, threatened or endangered species or to other native species. The TAG list includes, naturally, most native milkweed relatives and even species more distantly related.

“Luckily, none of our native plants is closely related to the [invasive]swallow-worts,” says Casagrande. “That makes [swallow-wort] a great candidate for classical biological control.  The Tag list also includes a suite of Eurasian plants you might expect these specialists to nibble at now and then, and even plants that could host these specialists’ relatives. The bar is high for these no-choice tests: biocontrols must prove they’ll die before they switch.”

Casagrande’s team examined five possible biocontrol specialists in their quarantine lab, including two European moth species (Hypena opulenta and Abrostola asclepiadis) that feed on swallow-wort leaves in their native range. The researchers wanted to be sure these insects wouldn’t jump to non-target plants on the TAG list, since the last thing anyone wants is a new pest dominating the landscape, threatening agriculture, native ecosystems, and rare plants.

Results?

Both leaf-eating moths “passed the acid test,” says Casagrande. However, scientists have only petitioned for and received approval for Hypena opulenta, which was approved by the USDA in September 2017. They may seek approval for Abrostela in the future but for now are focused on rearing, releasing, and studying the effectiveness of Hypena.  Releases in Canada started in 2013 when Hypena was approved there. Since then, it has established and spread but it is too soon to evaluate its effectiveness.

Releases in the U.S.

Hypena opulenta was released on Naushon Island, Massachusetts, in early September 2017 – the only release in the United States – where both black and pale swallow-wort occur. The field release was carried out by placing about 400 larvae in each of 4 large cages containing both swallow-wort species in sun and shade locations. The larvae will be allowed to grow and develop in the cages for a little while before the cages are opened to allow the larvae to escape and start establishing on the island.

Next steps?

Funding will be sought to support rearing of Hypena at University of Rhode Island and other locations in the U.S. Dr. Lisa Tewksbury, Manager of Biological Control at URI, is running the program. It will take a few years to get to the point of having sufficient moths to distribute widely.  Best practices for releasing and monitoring will be developed.

Thanks to the Northeast IPM Partnership and the interest and dedicated efforts of Casagrande and his research team, we now have the most effective tool to use against two highly invasive plant species that will also protect our native species and natural ecosystems.

 

Posted by Jil Swearingen

Jil recently retired from the federal government and works as an invasive species consultant. She has 28 years of experience working on invasive species at the county, regional and national level in areas of education, outreach and management. Jil initiated and co-founded the Mid Atlantic Invasive Plant Council and serves on the board. Jil serves as the Coordinator for the Mid Atlantic Early Detection Network, a project she initiated and co-developed, and she continues to serve as Chair for the Plant Conservation Alliance’s Alien Plant Working Group and manager of the Weeds Gone Wild website. Jil is lead author of the book, Plant Invaders of Mid-Atlantic Natural Areas. She was recently elected to serve on the Board of Directors of the Maryland Native Plant Society

 

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.