Month: January 2018

Act Now: Forest Protection in the 2018 Farm Bill

 

NOW is the time to advocate inclusion of important proposals in the 2018 Farm Bill. It is currently under consideration by the U.S. House of Representatives and Senate. If we miss this round of Farm Bill legislation, there won’t be another opportunity until 2023. Urge your Senators and Representative to support creation of the two grant-based funds described below.

 

What’s the issue?

We know that about 500 species of non-native insects and pathogens that attack native trees and shrubs are established in the United States. The number in Canada is 180 – there is considerable overlap.

Protecting the trees and their ecosystem services requires development and deployment of a set of tools aimed at either reducing the pests’ virulence or strengthening the tree hosts’ resistance or tolerance. Such strategies include biological control targetting the insect or pathogen and breeding trees resistant to the pest. Developing and employing these tools require sustained effort over years.

Unfortunately, the programs now charged with responding to introduced forest pests are only a ragged patchwork of university, state, and federal efforts. They provide neither the appropriate range of expertise nor continuity.  (For a more thorough discussion of the resources needed to restore tree species badly depleted by non-native pests, read Chapter 6 of Fading Forests III, posted here.)

 

CISP-backed Amendments

In order to begin filling the gaps, the Center for Invasive Species has proposed forest-related legislation for the Farm Bill currently being considered by Congress.

We propose creation of two new funds, each to provide grants to support tree-protection and restoration projects. We find that the expertise and facilities needed to plant and maintain young trees in the forest differ enough from those needed to research and test biological approaches to pest management and tree improvement that each deserves its own support.

Our first proposal would create a grant program managed by the National Institute of Food and Agriculture (NIFA) to provide long-term funding for research to restore tree species severely damaged by alien pests. The focus of the research would be on:

  • Biocontrol of pests threatening native tree species;
  • Exploration of genetic manipulation of the pests;
  • Enhancement of host- resistance mechanisms for individual tree species;
  • Development of other strategies for restoration; and
  • Development and dissemination of tools and information based on the research.

Entities eligible for funding under our proposal would include:

  • Agencies of the U.S. government;
  • State cooperative institutions;
  • A university or college with a college of agriculture or wildlife and fisheries; and
  • Non-profit entities recognized under Section 501(c)(3) of the Internal Revenue Code.

Our second proposal would provide long-term funding to support research into and deployment of strategies for restoring pest-decimated tree species in the forest. The source of funds would be the McIntire-Stennis program. The eligible institutions would be similar: schools of forestry; land grant universities; state agricultural and forestry experimental stations; and non-profit non-governmental organizations. Projects would integrate the following components into a forest restoration strategy:

  • Collection and conservation of native tree genetic material;
  • Production of propagules of native trees in numbers large enough for landscape scale restoration;
  • Site preparation of former of native tree habitat;
  • Planting of native tree seedlings; and
  • Post-planting maintenance of native trees.

In addition, competitive grants issued by this second fund would be awarded based on the degree to which the grant application addresses the following criteria:

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

(To request the texts of the proposed amendments, use the “contact us” button.)

 

A Growing Chorus Sees the Same Need

A growing chorus of scientists is calling for long-term funding for forest restoration programs based partly on recent scientific breakthroughs.  So this year’s Farm Bill provides a key opportunity for initiating such programs.

 

The NIFA Letter

The National Institute of Food and Agriculture asks scientists each year to suggest their highest priorities for the agency’s research, extension, or education efforts. In December, twenty-eight scientists replied by calling for setting up a special “division” within NIFA to fund breeding of pest-resistant tree species and associated extension.

The lead authors are Pierluigi (Enrico) Bonello, Ohio State University, and Caterina Villari, University of Georgia. The 26 co-signers are scientists from 12 important research universities, along with the U.S. Forest Service (the Universities of Georgia, California (Berkeley), Florida, Kentucky, Minnesota, and West Virginia; Auburn University; Michigan Technological University; North Carolina State University; Oregon State University; Purdue University; the State University of New York).

The scientists note that recent scientific advances have created a new ability to exploit genetic resistance found in the tree species’ natural populations. They assert that developing and deploying host resistance promises to improve the efficacy of various control strategies – including biocontrol – and provides a foundation for restoring forest health in the face of ever-more non-native forest pests.

The scientists’ proposal differs from CISP’s in calling for establishment of research laboratories and field study sites at several locations in the country. These would be permanently funded to conduct screening and progeny trials, and adequately staffed with permanent cadres of forest tree geneticists and breeders who would collaborate closely with staff and university pathologists and entomologists. The apparent model is the USDA Forest Service’ Dorena Genetic Resource Center  in Oregon. Dorena has had notable success with breeding Port-Orford cedar and several white pine species that are tolerant of the pathogens that threaten them.

 

POC trials at Dorena

In contrast, the CISP proposal relies largely on the chestnut model, which relies more on non-governmental organizations and wide-ranging collaboration. Our overall goal is similar, though: to provide stable funding for the decades-long programs needed to restore forest tree species.

 

American Chestnut Foundation chestnut growing in Northern Virginia

Why do we advocate grant programs instead of establishment of permanent facilities? We thought that Congress would be more likely to accept a smaller and cheaper set of grant programs in the beginning. Once the value of the long-term strategies is demonstrated more widely, supporters would have greater success in lobbying for creation of the permanent facilities.

Among the new technologies that would seem to justify the scientists’ assertion that success in breeding now appears to be more likely is the use of FT-IR and Raman spectroscopy and associated analysis of tree chemicals to identify individual trees within natural populations that have an apparent ability to tolerate disease-causing organisms. The leading scientist on the NIFA letter, Enrico Bonello, has used the technique to identify coast live oaks resistant to Phytopthora ramorum (the causal agent of sudden oak death. He is now testing whether the technique can identify Port-Orford cedar trees tolerant of the root-rot fungus Phytophthora lateralis and whitebark pines resistant to white pine blister rust.

I blogged about Enrico’s work on ash resistance to EAB here.) You can learn more about Enrico’s interesting work here.

The NAS Study

Meanwhile, the National Academies of Sciences, Engineering, and Medicine has launched a study on The Potential for Biotechnology to Address Forest Health. By the end of 2018, a committee of experts will report on the potential use of biotechnology to mitigate threats to forest tree health; identify the ecological, ethical, and social implications of deploying biotechnology in forests, and develop a research agenda to address knowledge gaps about its application. Funding for the study has been provided by The U.S. Endowment for Forestry and Communities; several agencies within the U.S. Department of Agriculture – Animal and Plant Health Inspection Service, U.S. Forest Service, National Institute of Food and Agriculture, Agricultural Research Service; and U.S. Environmental Protection Agency.

The Committee meetings are webcast, and there are other webinars on pertinent topics. You can view the schedule and sign up to receive alerts here.

Several people actively engaged in finding answers to invasive pest challenges have presented their views to the Committee, including Gary Lovett, Deb McCullough, Richard Sniezko, and me (!). You can find our presentations (Powerpoints and oral) at the above website. My talk focused on the crisis posed by non-native insects and pathogens and the need to evaluate the full range of possible response strategies for each host-pest situation. Application of genetic engineering technologies – in the absence of adequate resources for research and deployment of resistant hosts – cannot result in restoration of the host trees.

 

Background Information

Examples of tree-killing pests include such famous examples as chestnut blight and Dutch elm disease as well as less-well-known pests as soapberry borer. This map

indicates how many of the most damaging pests are established in each county of the 49 conterminous states. Descriptions of some of these insects and pathogens are provided here.

Additional tree-killing pests not included in the sources for the data supporting the map for various reasons would add to the numbers of pests in some states. Some non-native organisms have been introduced too recently, others attack palms or trees in Hawai`i; still others are native to Mexico and parts of the United States so were not included.

 

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.

 

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.