funding – Page 4 – Center for Invasive Species Prevention

Urgent Update on Beech Leaf Disease

banding symptoms of beech leaf disease; photo by Dr. Chagas de Freitas, Ohio State

Experts on beech leaf disease (BLD) hold conference calls every two months. I reported on the May meeting earlier in July. The July conference call of the experts emphasized not only the alarming spread of the disease but also the dilemmas frustrating efforts to slow its spread and protect beech.

Jerry Carlson, chief of forest health protection for the New York Department of Environmental Conservation called beech leaf disease “the next chestnut blight”.

Yet forestry, plant health, and conservation entities have been slow to support research needed to develop protective measures.

As was noted by participants, 10 years after scientists from Lake MetroParks (in Cleveland) first detected disease symptoms, scientists still are unsure about all aspects of BLD and how it spreads. Experts agree that the nematode (Litylenchus crenatae ssp mccannii) must be present to initiate the disease. Other possible factors, especially fungi in the genus Colletotrichum, appear to play important roles in causing the symptoms.

The lack of clarity about the causal agent means that USDA APHIS has not recognized the disease as a priority species for tracking. APHIS has provided some funds. However, scientists seeking to obtain funding through the Plant Pest and Disease Management and Disaster Prevention Program [laid out in the Plant Protection Act’s Section 7721] can’t get traction. Other funding sources also don’t quite fit. For example, the National Science Foundation funds basic, hypothesis-driven, research – not the more applied science needed to address BLD. Some participants wondered whether funding might be sought from wildlife-oriented sources, since beech are so important in providing hard mast, den and nest sites, etc., for a variety of wildlife.

Participants discussed ways to raise awareness – and alarm – in order to build a broader coalition. This effort should include Europe. Although the disease has not yet been detected in Europe, the native beech is vulnerable.

European beech in Rhode Island infected by BLD; photo by Dr. Nathaniel A. Mitkowski, University of Rhode Island

Data indicate that the disease is now significantly more widespread than was known last year. That is, BLD is more widespread from New York to Maine, with New Hampshire reporting its first detection. To the west, BLD has been detected in Michigan and in a forest fragment in western Ohio (near Toledo). Disease severity has also intensified. Of course, the disease is present at least a year before it is detected because leaf symptoms appear in the spring following infection. Therefore its presence is probably wider.

map of BLD presence as of early July 2022 (some states have not yet reported); note the many counties in fuschia – 2022 detections

While mortality of mature beech is still rarely documented, this might be related to difficulties determining the cause of mortality during standard forest health surveys. Participants discussed how to rectify this situation.

Meanwhile, concern is rising – as reflected in Dr. Carlson’s statement.

You can help by asking your state and national officials and conservation organizations to support applied research aimed at clarifying how the disease spreads, what ecological conditions are conducive to disease, improved detection and prediction tools, and possible containment strategies. Let’s overcome the roadblocks impeding protection of this magnificent and ecologically vital tree species.

Is this not worth protecting?

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.

For a detailed discussion of the policies and practices that have allowed these pests to enter and spread – and that do not promote effective restoration strategies – review the Fading Forests report at http://treeimprovement.utk.edu/FadingForests.htm

www.fadingforests.org

Funding APHIS & USFS – speak up!

To forest pest mavens:

The House Appropriations Committee has acted on funding for APHIS & USFS in Fiscal Year (FY) 23 – which begins on October 1. While several programs have been funded at an adequate level, funding for others – e.g., APHIS’ “Tree & Wood Pests) still falls short. Please contact your senators and ask them to urge members of the Senate Appropriations Committee to increase funding for this program. Members of the Senate Agriculture and Interior Appropriations subcommittees (those with jurisdiction) are listed at the end of this blog. My rationale for the “asks” are in my earlier blog.

APHIS funding in $ millions

Program	FY 2021 (millions)	FY 2022 enacted	FY 2023 Pres’ request	Our ask	House bill
Tree & Wood Pests	$60.456	$61.217	$62.854	$70	$62.562
Specialty Crops	$196.553	$209.553	$219.533	$219	$219.698
Pest Detection	$27.733	$28.218	$29.854	$30	$29.825
Methods Development	$20.844	$21.217	$21.854	$23	$31.807

The House bill provides significant funding for many traditional agricultural concerns – livestock health, cotton pests, citrus diseases and pests. Programs we lobbied for received less than the Administration requested with the exceptions of Methods Development and Specialty Crops. I found no explanation for the $10 million increase for methods development.

The Committee Report specifies increases for several pests under Specialty Crops, e.g., citrus and grapes. The report also specifies that $18.3 million should be spent to control spotted lanternfly, which is a pest of both agriculture (especially grapes) and forests. The Committee asks APHIS to keep it informed about progress tackling this pest. (Rep. Andy Harris, ranking Republican on the Agriculture Appropriations subcommittee, has an active SLF infestation in his district.)

The report also instructs APHIS to maintain funding for Asian longhorned beetle at previous levels – within the Tree & Wood Pest account. This means that any savings arising from APHIS’ declaration that parts of the Ohio infestation have eradicated must still be spent on this pest. There are several outbreaks where such funds might be spent, including in New York, Massachusetts, remaining areas in Ohio, and South Carolina.

As in past years, the House Report reiterates members’ expectation that the USDA Secretary will use the authority provided in this bill to transfer funds from the USDA Commodity Credit Corporation to obtain funds to address animal and plant pest emergencies that threaten American agriculture. The Committee has appropriated additional money which is intended to enhance, not replace, use of CCC funds. [The Office of Management and Budget has severely curtailed APHIS access to emergency funds.]

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The House Committee has asked that USFS develop a research program that reflects priorities on, inter alia, invasive species. This falls short of my request for earmarking a specific (small) percentage of research funding for invasive species, but it does show Congressional interest in this problem.

one of the diseases needing USFS research: beech leaf disease (photo by Dr. Chagas de Freitas)

In the part of the budget that funds actual management work, Forest Health Management, apparently the $52 million appropriation reflects only a modest increase of funding for managing invasive species everywhere – on federal lands, i.e. National forests and non-federal lands, i.e., “coop” lands. I appreciate the attention to invasive species, especially emerald ash borer; but worry about allocating most funding to managing the impacts rather than pro-actively addressing introduction and spread to new areas.

USFS funding in $ millions

Program	FY 2021	FY 2022 enacted	FY 2023 Pres’ request	My ask	House bill
R&D		$296.6	$317.8	$317.8	$360.4
[FIA]					$37.7 ($15 M increase)
S&P FHM	$46,232	same?	$59.232	$82	$52.232

Research & Development – The Committee Report noted members’ interest in funding specific laboratories, programs, & projects, including several listed areas. The Committee expects USFS to develop a research program that reflects members’ priorities & other priorities critical to forest health, particularly with respect to climate change adaptation, preventing spread of insects and diseases, and watershed improvement

The report states several times that the USFS should assist in control of the emerald ash borer and other invasive pests, especially in areas where ash tree mortality has been high. Such statements are under State and Private Forestry, under both the Forest Health Management and Urban and Community Forests programs. The Committee earmarks $4 million under UCF for management & reforestation – including tree planting & removals — in communities most severely impacted by EAB and other pests. The efforts should prioritize regional, multi-organization collaborations in urban communities most severely impacted by invasive pests like EAB. The committee asks for a report from USFS on major invasive species and progress of remediation and replanting programs.

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Key Members of the Senate Appropriations Committee

STATE	MEMBER	APHIS APPROP	USFS APPROP
AK	Lisa Murkowski		X
Calif	Diane Feinstein	X	X
FL	Marco Rubio		X
HI	Brian Schatz	X
IN	Mike Braun	X
KS	Jerry Moran	X
KY	Mitch McConnell	X	X
MD	Chris Van Hollen		X
ME	Susan Collins	X
MS	Cindy Hyde-Smith	X	X
MO	Roy Blunt	X	X
MT	Jon Tester	X	X
ND	John Hoeven	X
NM	Martin Heinrich	X	X
OR	Jeff Merkley	X	X
RI	Jack Reed		X
TN	Bill Hagerty		X
VT	Patrick Leahy	X	X
WV	Shelly Moore Capito		X
WI	Tammy Baldwin	X

Posted by Faith Campbell

www.fadingforests.org

Updates on 1) hemlocks 2) shot hole borers/Fusarium & 3) beech leaf disease

symptoms of beech leaf disease; photo by Dr. Chagas de Freitas

Three webinars during April and May provided updates on efforts to address three non-native, tree-killing pests: hemlock woolly adelgid (HWA), link invasive shot hole borers (ISHB), link and beech leaf disease (BLD) link. I attended each and summarize here.

Hemlock conservation in North Carolina – the NC Hemlock Restoration Initiative (HRI) see SaveHemlocksNC.org

The webinar was recorded at Hope for the Hemlocks: HWA Management Approaches on Public and Private Lands in North Carolina. You probably need to be a member of the Natural Areas Association to watch the archived version.

I was pleased to learn about the major effort under way in North Carolina, where eastern and Carolina hemlocks are extremely important components of multiple ecosystems. In 2013, the Commissioner of Agriculture decided to make protecting hemlocks a signature project. He wanted to ensure that three state agencies – the Forest Service, Wildlife Department, and State Parks – worked together to improve the efficacy of treating trees. (Treatments available at the time were expensive and time-consuming.)

HRI treatment at Conestee Falls; HRI photo

Thom Green described the result: North Carolina’s Hemlock Restoration Initiative (HRI). The initiative is administered by the Western North Carolina Communities – a non-governmental organization with strong connections to rural communities and a history of successful collaborative projects that support agriculture and forestry. It engages state agencies, local and county governments, local NGOs, and federal agencies and works on both public and private lands with the goal of ensuring that hemlocks can survive to maturity.

HRI staff work with local partners to identify priority hemlock conservation areas (HCAs). It then sends a “strike team” to guide the partners in treating as many trees as possible. (North Carolina allows non-licensed volunteers to apply pesticides under supervision; also, landowners can treat trees on their own property.) These collaborative projects can treat up to 1,000 trees per day.

The chemicals used are imidacloprid and, where poor tree health justifies emergency treatment, dinotefuran. These are usually applied as a soil drench because it is easier for people to transport the equipment into the woods. Bark spray is used in sensitive areas. They have found that imidacloprid provides five to seven years of protection. A new product, CoreTech, is even easier to transport and works much faster than imidacloprid, however, it costs more.

The HRI believes it is minimizing non-target impacts of the neonictenoid imidacloprid because:

hemlocks are pollinated by wind, not insects
- hemlocks don’t exude resins that attract insects
- pesticide applications are tightly targetted at the base of trunk, with 10-foot setbacks from water
- long intervals between treatments (5 – 7 years) allow soil invertebrates to recover

The program has treated 100,000 trees between 2016 and 2021 on state and private lands. Now they are starting the second round of treatments for trees treated at the beginning of the program.

Treatment priorities are based primarily on the extent to which the trees are able to take up the chemical, evaluated by the percentage of the crown that is alive and the density of foliage. Since imidacloprid can take a year to reach the canopy of a mature tree, it is used only on trees with greater than half the crown rated as healthy. When trees have a lower status, dinotefuran is added (because it can reach the canopy within weeks). Trees with less than 30% live crown are not treated.

The Initiative also supports biocontrol programs. It has assisted releases of Laricobius nigrinis (a beetle in the family Derodontidae) and helps volunteers monitor releases and survival. Dr. Green reports that L. nigrinis has spread almost throughout western North Carolina but that questions remain regarding its impact on tree health. He thinks biocontrol is not yet reliable as stand-alone tool; success will require a suite of predatory insects.

Forest Restoration Alliance potting hemlock seedlings; HRI photo

The HRI measures the success of various treatments (Hurray!). “Impact plots” are established at the start of treatment. Staff or volunteers return every three years to monitor all aspects of the health of a few designated trees – including untreated ones. So far, they have seen encouraging responses in crown density and new growth.

Invasive Shot Hole Borers (ISHB) in California

See www.ishb.org and video recordings of the meeting at:

https://youtu.be/RyqJYyLkshk (Day 1); and https://youtu.be/kWmtcbjTczw (Day 2)

A host of scientists from California spent two full days describing research and management projects funded by specific state legislation – Assembly Bill (AB)-2470 on two invasive shot hole borers.

Adoption of this legislation resulted largely from lobbying by John Kabashima. Additional funding was provided by CalFire (the state’s forestry agency). The agency responsible for managing invasive species – California Department of Food and Agriculture (CDFA) had designated these organisms as not a threat to agriculture. So it did not fund many necessary activities.

The Problem and Where It Is

“Fusarium dieback” is the disease caused by this insect-pathogen complex. The insects involved are two ambrosia beetles in the Euwallacea genus – the polyphagous (E. whitfordiodendrus) and Kuroshio (E. Kuroshio) shot hole borers. link to DMFAccording to Dr. Bea Nabua-Behermann, Urban Forestry and Natural Resources Advisor with University of California Cooperative Extension (UCCE), other fungi are present on both beetle species but its matching Fusarium sp. is the principal associated fungus and is required for the beetle’s reproduction. These are Fusarium euwallaceae and F. kuroshium.

As of spring 2022, the beetle/fungus complex has spread as far north as Santa Barbara /Santa Clarita; and inland to San Bernardino and Riverside (see the map here). They are very widespread in Orange and San Diego counties. At least 65 tree species in southern California are reproductive hosts (globally, it is 77 species; see full list here). The preferred and most succeptible hosts are several species in the Acer, Parkinsonia, Platanus, Quercus, and Salix genera. Box elder (A. negundo) is so susceptible that it is considered a sentinel tree.

Because the beetles spend most of their life inside trees, their life cycle leaves few opportunities to combat them. Females (only) fly but tend to bore galleries on their natal tree. Several speakers on the webinar said management should focus on heavily infested “amplifier trees”. Much spread is human assisted since the beetles can survive in dead wood for months if it is damp enough for the fungus. Possible vectors are green waste, firewood, and even large wood chips or mulch.

Management – from Trapping to Rapid Response to Restoration

Akiv Eskalen of University of California Davis discussed trapping and monitoring techniques to confirm presence of the insect and pathogen. Also, he talked about setting priorities for treating trees based on the presence of reproductive hosts, host value, infestation level, and whether the trees pose a safety hazard. The disease causes too little damage to some hosts to warrant management. He emphasized the importance of preventing spread. This requires close monitoring of infested trees to see whether beetles move to neighbors. Dr. Eskalen described a major and intensive monitoring and treatment program at Disneyland. The 600 acres of parks, hotels, and parking lots have ~16,000 trees belonging to 681 species.

Several speakers described on-going efforts in Orange County. Danny Hirchag (IPM manager for Orange County Parks) described how his agency is managing 60,000 acres of variable woodlands containing 42,000 trees, of which 55% are hosts of ISHB and their associated fungi. Of greatest concern are California sycamore and coast live oak in areas of heavy public use. The highest priority is protecting public safety; next is protecting historic trees (which can’t be replaced); third is minimizing impacts to ecosystem services. Orange County Parks is currently removing fewer than 50 trees each year. Hirchag noted the importance of collaborating in the research trials conducted by the University of California Cooperative Extension.

infested California sycamore; photo by Bea Nabua-Behermann

Maximiliano Regis and Rachel Burnap, of County of Los Angeles Department of Agricultural Commissioner/Weights and Measures, described Los Angeles County’s efforts more broadly. The challenge is clear: LA County has more than 160 parks. In 2021, they placed nearly 2,500 traps, mapped infected trees, carried out on-ground surveys to find amplifier trees, removed both amplifier and hazard trees (using funds provided by CalFire), and educated the public. Their efforts were guided by an early detection-rapid response (ED/RR) Plan (2019) developed by Rosi Dagit (see below). While London plane trees (Platanus x hispanica) and California sycamores (Platanus racemose) were initially most affected, now black locusts (Robinia pseudoacacia) and box elders (Acer negundo) are succumbing. [Note: both are widespread across North America.] The researchers are trying to determine why some areas are largely untouched, despite the presence of the same tree species. Regis and Burnap noted the increasing difficulty getting confirmation of the pathogen’s presence because laboratories are overwhelmed. They continue looking for funding sources.

Rosi Dagit, Senior Conservation Biologist, Resource Conservation District of the Santa Monica Mountains, described the creation of that ED/RR system for Los Angeles County as a whole, without regard for property lines. Participants established random study plots across the entire Santa Monica Mountains Natural Recreation Area (NRA), based on proximity to areas of particularly sensitive ecological concerns. The fact that the NRA’s forests are aging and that the risk of infestations is especially high in riparian forests helped persuade policy-makers to fund the effort. The accompanying rapid response plan informs everyone about what to do, who should do it, and who pays. This information incorporates agencies’ rules about what and where to plant. It also provides measures to evaluate whether the action was effective. It did take more than two years for the county to set staffing needs etc.

John Kabashima link discussed his criteria for replanting and ecosystem restoration following tree removal in the southern California region. He recommends prompt removal of amplifier trees – especially box elder and California sycamore. He relies on replanting guidance developed by UC-Irvine (which is on the website) – especially avoiding monocultures. Kabashima reiterated the importance of close monitoring to track beetle populations and responding quickly if they build up.

Economics of Urban Forests and Cities Most at Risk

Karen Jetter (an economist at the UC Agriculture Issues Center) has developed a model to compare the costs of an early detection program to the environmental and monetary costs of infestation by Fusarium disease. She noted that early detection and monitoring programs are often hard to justify because — when they are successful — nothing changes! She found that averted or delayed costs (including tree removals, lost ecosystem services, lost landscape asset value [replanting value] and the cost to replant) always far exceeded the cost of monitoring programs. Unfortunately, a written report about this effort (Jetter, K., A. Hollander, B.E. Nobua-Behrmann, N. Love, S. Lynch, E. Teach, N. Van Dorne, J. Kabashima, and J. Thorne. 2022. Bioeconomic Modeling of Invasive Species Management in Urban Forests; Final Report) appears to be available only through the University of California “collaborative tools” website dedicated to practitioners and stakeholders engaged on ISHB issues. If you are not a member of the list, contact me using the comment button and ask that I send it to you. Include your email address (the comment process makes determining emails difficult if not impossible.)

Shannon Lynch (UC Davis) developed a model to estimate vulnerability of urban areas based on phylogenetic structure (relationship between tree species), host abundance, and number of beetle generations/year (linked to temperature). She found that areas with less favorable host communities can become vulnerable if the climate becomes favorable. Where the host community is already favorable, climate not important.

She evaluated 170 California cities based on their tree inventories. The cities at highest risk were San Diego, Los Angeles, the San Francisco Bay area, and the Central Valley – e.g., Sacramento. For areas lacking tree inventories, she based her risk determination on the estimated number of generations of beetles per year – based on climate. This analysis posited a very high risk in the eastern half of southern California and the Central Valley. Participants all recognized the need to apply this model to cities in Arizona and Nevada.

Possible Management Strategies

Shannon Lynch (UC Davis) studied whether endophytes might be used to kill the Fusarium fungi. She reported finding 771 fungal strains and 657 bacterial strains in tree microbiomes. Some of the fungal isolates impeded growth of the Fusarium fungi in a petri dish. She began testing whether these fungi can be used to inoculate cuttings that are to be used for restoration. She also planned to test more endophytes, and more native plant species to explore creation of a multi-fungus cocktail.

Richard Stouthamer of UC Riverside is exploring possible biocontrol agents. Of three he has evaluated, the most promising is Phasmastichus sp., which is new to science. He is still trying to establish laboratory cultures so he can test its host specificity.

Beech Leaf Disease (BLD) – Ongoing Research by the BLD Research Group

See bldresearch@lists.osu.edu

At this meeting, scientists described research aimed at improving basic understanding of beech leaf disease’s causal agents, its mechanisms of spread, etc. Their findings are mostly preliminary.

These findings are of greatest importance now:

presence of the nematodes varies considerably across leaf surface – if one collects samples from the wrong site on leaf, one won’t detect nematode (Paulo Vieria, Agriculture Research Service)
- developing predictive risk maps that combines temperature, humidity, elevation, soils (Ersan Selvi, Ohio State). So far, he has found that BLD is greater in humid areas – including under closed forest canopies. The USFS is funding studies aimed at incorporating disease severity in detection apps.
- determining extent of nematode presence. Sharon Reed of Ontario has found nematode DNA in trap fluids throughout the Province. It is much more common at known disease sites. Reed is also studying the presence of arthropods on beech leaves and buds.

Longer term findings and questions

possible vectors:
- nematode DNA has been detected from birds – although it is not clear whether the DNA came from bird feces, feathers, or dust (DK Martin)
- a few live nematodes have been extracted from the excrement of caterpillars that fed on infected leaves (Mihail Kantor, ARS)
- nematode damage to leaves:
  - presence of the nematode in leaf buds before they open (Vieria and Joe Mowery, both ARS). The nematode can create considerable damage in leaf buds before they open. Nematodes are present as early as October of the preceding year.
  - damage to leaves by nematode (Mowery, ARS) Leaf epidermal cells are distorted, stomata blocked, chlorobasts are larger than normal, irregular shape
- possible management tools
  - are there parasites that might attack the nematode? (Paulo Vieria, ARS)
  - experimental treatment of infested trees using phosphite (Kandor, ARS)
- ecology: how do root microbiomes compare on infested and healthy trees? (Caleb Kime, Ohio State; and David Burke, Vice President for Science at Holden Arboretum)

infested European beech in Rhode Island; photo by Dr. Nathanial A. Mitkowski

Posted by Faith Campbell

www.fadingforests.org

Invasions cost protected areas more than $22 billion in 35 years

Burmese python in Everglades National Park; photo by Bob Reed, US FWS

Scientists continue to apply data collected in an international database (InvaCost; see “methods” section of Cuthbert et al.; full citation at end of this blog) to estimate the economic costs associated with invasive alien species (IAS). These sources reported $22.24 billion in economic costs of bioinvasion in protected areas over the 35-year period 1975 – 2020. Because the data has significant gaps, no doubt invasions really cost much more.

Moodley et al. 2022 (full citation at end of this blog) attempt to apply these data to analyze economic costs in protected areas. As they note, protected areas are a pillar of global biodiversity conservation. So it is important to understand the extent to which bioinvasion threatens this purpose.

Unfortunately, the data are still too scant to support any conclusions. Such distortions are acknowledged by Moodley et al. I will discuss the data gaps below a summary of the study’s findings.

The Details

Of the estimated $22.24 billion, only 4% were observed costs; 96% were “potential” costs (= extrapolated or predicted based on models). Both had generally increased in more recent years, especially “potential” costs after 1995. As is true in other analyses of InvaCost data, the great majority (73%) of observed costs covered management efforts rather than losses due to impacts. The 24% of total costs ascribed to losses, or damage, exceeded the authors’ expectation. They had thought that the minimal presence of human infrastructure inside protected areas would result in low records of “economic” damages.

The great majority (83%) of reported management costs were reactive, that is, undertaken after the invasion had occurred. In terrestrial environments, there were significantly higher bioinvasion costs inside protected areas than outside (although this varied by continent). However, when considering predicted or modelled costs, the importance was reversed: expected management costs represented only 5% while these “potential” damages were 94%.

Higher expenditures were reported in more developed countries – which have more resources to allocate and are better able to carry out research documenting both damage and effort.

More than 80% of management costs were shouldered by governmental services and/or official organizations (e.g. conservation agencies, forest services, or associations). The “agriculture” and “public and social welfare” sectors sustained 60% of observed “damage” and 89% of “mixed damage and management” costs respectively. The “environmental” and “public and social welfare” sectors together accounted for 94% of all the “potential” costs (predicted based on models) generated by invasive species in protected areas; 99% of damage costs. With the partial exception of the agricultural sector, the economic sectors that contribute the most to movement to invasive species are spared from carrying the resulting costs.

Lord Howe Island, Australia; threatened by myrtle rust; photo by Robert Whyte, *via* Flickr

Invasive plants dominated by numbers of published reports – 64% of reports of observed costs, 79% of reports of “potential”. However, both actual and “potential” costs allotted to plant invasions were much lower than for vertebrates and invertebrates. Mammals and insects dominated observed animal costs.

It is often asserted that protected areas are less vulnerable to bioinvasion because of the relative absence of human activity. Moodley et al. suggest the contrary: that protected areas might be more vulnerable to bioinvasion because they often host a larger proportion of native, endemic and threatened species less adapted to anthropogenic disturbances. Of course, no place on Earth is free of anthropogenic influences; this was true even before climate change became an overriding threat. Plenty of U.S. National parks and wilderness areas have suffered invasion by species that are causing significant change (see, for example, here, here, and here).

Despite Best Efforts, Data are Scant and Skewed

Economic data on invasive species in protected areas were available for only a tiny proportion of these sites — 55 out of 266,561 protected areas.

As Moodley et al. state, their study was hampered by several data gaps:

Taxonomic bias – plants are both more frequently studied and managed in protected areas, but their reported observed costs are substantially lower than those of either mammals or insects.
The data relate to economic rather than ecological effects. The costliest species economically might not cause the greatest ecological harm.
Geographical bias – studies are more plentiful in the Americas and Pacific Islands. However, studies from Europe, Africa and South America more often report observed costs. The South African attention to invasive species (see blogs here, here, and here), and economic importance of tourism to the Galápagos Islands exacerbate these data biases.
Methodological bias – although reporting bioinvasion costs has steadily increased, it is still erratic and dominated by “potential” costs = predictions, models or simulations.

I note that, in addition, individual examples of high-cost invasive species are not representative. The highest costs reported pertained to one agricultural pest (mango beetle) and one human health threat (mosquitoes).

Great Smokey Mountains National Park; threatened by mammals (pigs), forest pests, worms, invasive plants … Photo by Domenico Convertini *via* Flickr

As these weaknesses demonstrate, a significant need remains for increased attention to the economic aspects of bioinvasion – especially since political leaders pay so much greater attention to economics than to other metrics. However, the reported costs – $22.24 billion over 35 years, and growing! – are sufficient in the view of Moodley et al. to support advocating investment of more resources in invasive species management in protected areas, including – or especially – it is not quite clear — preventative measures.

SOURCES

Cuthbert, R.N., C Diagne, E.J. Hudgins, A. Turbelin, D.A. Ahmed, C. Albert, T.W. Bodey, E. Briski, F. Essl, P.J. Haubrock, R.E. Gozlan, N. Kirichenko, M. Kourantidou, A.M. Kramer, F. Courchamp. 2022. Bioinvasion cost reveals insufficient proactive management worldwide. Science of The Total Environment Volume 819, 1 May, 2022, 153404

Moodley, D., E. Angulo, R.N. Cuthbert, B. Leung, A. Turbelin, A. Novoa, M. Kourantidou, G. Heringer, P.J. Haubrock, D. Renault, M. Robuchon, J. Fantle-Lepczyk, F. Courchamp, C. Diagne. 2022. Surprisingly high economic costs of bioinvasions in protected areas. Biol Invasions. https://doi.org/10.1007/s10530-022-02732-7

Posted by Faith Campbell

or www.fadingforests.org

Comment to APHIS on its Strategic Plan

APHIS is seeking stakeholder input to its new strategic plan to guide the agency’s work over the next 5 years.

The strategic plan framework is a summary of the draft plan; it provides highlights including the mission and vision statements, core values, strategic goals and objectives, and trends or signals of change we expect to influence the agency’s work in the future. APHIS is seeking input on the following questions:

Are your interests represented in the plan?
Are there opportunities for APHIS to partner with others to achieve the goals and objectives?
Are there other trends for which the agency should be preparing?
Are there additional items APHIS should consider for the plan?

range of American beech – should APHIS be doing more to protect it from 3 non-native pests?

The strategic plan framework is available at https://www.regulations.gov/document/APHIS-2022-0035-0001

To comment, please visit: https://www.regulations.gov/docket/APHIS-2022-0035

Comments must be received by July 1, 2022, 11:59pm (EST).

Posted by Faith Campbell

or www.fadingforests.org

Help Ensure Best Pest-Countering Programs Possible!

This blog asks YOU!!! to support funding for key USDA programs. Each is essential for protecting the resilience of the Nation’s forests in the face of invasive pests. Please help by contacting your members of the House and Senate Appropriations Committees. I provide a list of members – by state – at the end of this blog.

While the two key federal programs overlap, they are separately managed: USDA’s Animal and Plant Health Inspection Service (APHIS) and USDA’s Forest Service (USFS). These two agencies are funded by different subcommittees of the House and Senate’s Appropriations committees. APHIS is funded by the Subcommittees on Agriculture and Related Agencies. USFS is funded by the Subcommittees on Interior.

Your letter or email need be no more than a couple paragraphs. To make the case for greater funding, feel free to pick-and-choose from the information that follows. Your greatest impact comes from speaking specifically about what you know and where you live.

These are the specific dollar things we’d like you to ask for. The rationale for each is below.

Appropriations for APHIS programs (in $millions)

Program	FY 2021	FY 2022 CR	FY 2023 Pres’ request	Please ask
Tree & Wood Pest	$60.456	$61.217	$63	$70
Specialty Crops	$196.553	$209.553	$219	$219
Pest Detection	$27.733	$28.218	$29	$30
Methods Development	$20.844	$21.217	$22	$23

Appropriations for USFS programs (in $millions)

Program	FY 2021	FY 2022 CR	FY 2023 Pres’ request	Please ask
Forest Health Protection Coop Lands	$30.747	$30.747	$36,747	$51
FHP Federal Lands	$15.485	$15.485	$22.485	$32
Research & Development	$258.760	$258.760	$317.773	$317.733
% for forest invaders	~1%?	?	0	$16 M

Background on the Threat

I’m sure you are familiar with the many ecosystem services provided by America’s forests and woodlands – wildland, rural, and urban. (Besides – maybe you just love trees!) I assume you also know that these forests are under threat from a growing number of non-native insects and pathogens.

For a quick review, see earlier blogs re: 1) an estimate that 41% of forest biomass in the “lower 48” states is at risk to mortality caused by the most damaging 15 species; black ash swamps of the upper Midwest; unique forest ecosystems of Hawai`i; riparian forests in the far West; stream canyons of the Appalachian range and; high-elevation forests of the West; and unique forests of Southwest Oregon. Also, see the thorough discussion of these pests’ impacts in Invasive Species in Forests and Grasslands of the United States: A Comprehensive Science Synthesis for the United States Forest Sector – blog; link available here]

Meanwhile, newly-discovered pests continue to appear and require research and management. The most troubling current example is beech leaf disease. It’s killing beech trees from Ohio to Maine and south to Virginia.

These introduced pests usually first appear in cities or suburbs because they arrive on imported goods shipped to population centers. The immediate result is enormous damage to urban forests. A recently published article (“Hotspots of pest-induced US urban tree death, 2020–2050”), projects that, by 2050, 1.4 million street trees in urban areas and communities will be killed by introduced insect pests. Removing and replacing these trees is projected to cost cities $30 million per year. Additional urban trees – in parks, other plantings, on homeowners’ properties, and in urban woodlands – are also expected to die.

As we know, newly-arrived pests don’t stay in those cities. Some spread on their own. Others are carried far and wide on firewood, plants, patio furniture, even storage pods. And so they proliferate in rural and wildland forests, including US National Forests.

As we know too well, many pests—especially the highly damaging wood-borers—arrive in inadequately treated crates, pallets, and other forms of packaging made of wood. Other pests—e.g., spotted lanternfly —take shelter, or lay their eggs, in or on virtually any exposed hard surface, such as steel or decorative stone.

Imports from Asia have historically transported the most damaging pests. Unfortunately, imports from Asia have reached unprecedented volume – currently they’re running at a rate of 20 million shipping containers per year. Research findings lead to an estimate that at least 7,500 of these containers are carrying a tree-killing pest. The “Hotspots” authors found that if a new woodborer that attacks maples or oaks is introduced, it could kill 6.1 million trees and cost American cities $4.9 billion over 30 years. The risk would be highest if this pest were introduced to the South – and southern ports are receiving more direct shipments from Asia!

Some types of pests—especially plant diseases and sap sucking insects —come on imported plants. A principle example is sudden oak death (SOD; and which attacks more than 100 species of trees and shrubs). Other examples are the rapid ʻōhiʻa death pathogen that threatens Hawai`i’s most widespread tree, ʻōhiʻa lehua; and beech leaf disease, a newly discovered threat that is killing beech trees in a band stretching from Ohio to Maine.

Background on Specific USDA Funding Requests

APHIS

To reduce the risk of new pest introductions and strengthen response to many important pests, please ask your member of Congress and Senators to support appropriations that support key APHIS programs in the table above. (I assume you know that APHIS is responsible for preventing introduction and spread of invasive pests. While most port inspections are carried out by the Department of Homeland Security’s Bureau of Customs and Border Protection, APHIS sets the policy guidance. APHIS also inspects imports of living plants.)

Thank your member for the incremental increases in funding for these programs in FY22 but suggest that a more substantial investment is warranted.

The Tree and Wood Pests account supports eradication and control efforts targeting principally the Asian longhorned beetle (ALB) and spongy (formerly gypsy) moth. Eradicating the ALB normally receives about two-thirds of the funds. The programs in Massachusetts, New York, Ohio, and South Carolina must continue until eradication succeeds.

The Tree and Wood Pests account formerly also funded APHIS’ emerald ash borer (EAB) regulatory program. APHIS terminated this program in January 2021. The probable result is that EAB will spread more rapidly to the mountain and Pacific Coast states. Indeed, the “Hotspots” article identified Seattle and Takoma as likely to lose thousands of ash trees in coming decades. This result shows what happens when APHIS programs are inadequately funded.

Re: the plant diseases and sap sucking insects that enter the country on imported plants, APHIS’ management is through its Specialty Crops program. Repeatedly, SOD-infected plants and have been shipped from nurseries in the Pacific Coast states to vulnerable states across the East and South. Clearly this program needs re-assessment and – perhaps – additional funding.

The Specialty Crops program also is home to APHIS’ efforts to counter the spotted lanternfly, which has spread from Pennsylvania to Maryland, Delaware, New Jersey, Virginia, West Virginia, Ohio, even Indiana. This pest threatens both native trees and agricultural crops – including hops, grapes, apples, and more. California has adopted a state quarantine in hopes of preventing its introduction to that state. Still, APHIS has not established a quarantine.

Please ask the Congress to support the Administration’s request for $219 million for the Specialty Crops program. However, urge them to adopt report language to ensure that APHIS allots adequate funding under this budget line to management of both sudden oak death and spotted lanternfly.

Two additional APHIS programs are the foundation for effective pest prevention. First, the Pest Detection program is key to the prompt detection of newly introduced pests that is critical to successful pest eradication or containment. Please ask the Congress to fund Pest Detection at $30 million. Second, the “Methods Development” program enables APHIS to improve development of essential detection and eradication tools. Please ask the Congress to fund Methods Development at $23 million.

Please ask your member of Congress to support the Administration’s request for a $50.794 million fund for management of emergencies threatening America’s agricultural and natural resources. This program includes a $6 million increase for work with the Climate Conservation Corps specifically targetting invasive species. Although the details are not yet clear, the program’s focus will be to improve surveillance and mitigation methods.

US Forest Service

The USFS has two programs critical to managing non-native tree-killing pests – Forest Health Management (or Protection; FHP) and Research and Development (R&D). FHP provides technical and financial assistance to USFS units (e.g., National forests and regions), other federal agencies, states, municipalities, and other partners to detect and manage introduced pests – including several that APHIS regulates and dozens that it does not. R&D funds efforts to understand non-native insects, diseases, and plants – which are usually scientific mysteries when they first are detected. Of course, this knowledge is crucial to effective programs to prevent, suppress, and eradicate the bioinvader. See the table at the beginning of the blog for specific funding requests for each program.

The Forest Health Management Program (FHP) has two funding streams: Federal Lands and Cooperative Lands (all forests under non-federal management, e.g., state and private forests, urban forests). Both subprograms must be funded in order to ensure continuity of protection efforts – which is the only way they can be effective. Some members of Congress prefer to focus federal funding on National forests. However, allowing pests to proliferate until they reach a federal forest border will only expose those forests to exacerbated threats. Examples of tree-killing pests that have spread from urban areas to National forests include the hemlock woolly adelgid, emerald ash borer, polyphagous and Kuroshio shot hole borers, sudden oak death, and laurel wilt disease. [All profiled here]

Adequate funding for FHP is vital to realizing the Administration’s goals of ensuring healthy forests and functional landscapes; supporting rural economies and underserved communities; enhancing climate change adaptation and resilience; and protecting biological diversity.

Please ask your Member of Congress and Senators to provide $51 million for work on non-federal cooperative lands. This level would partially restore capacity lost over the last decade. Since Fiscal Year (FY) 2010, spending to combat 11 specified non-native insects and pathogens fell by about 50%. Meanwhile, the pests have spread. Also, please ask your Member and Senators to support a $32 million appropriation for the Federal Lands subprogram for FY23 which is allocated to pests threatening our National forests directly.

A vital component of the FHP program is its leadership on breeding pest-resistant trees to restore forests decimated by pests. FHP’s Dorena Genetic Resource Center, in Oregon, has developed Port-Orford cedar seedlings resistant to the fatal root-rot disease. and blog. These seedlings are now being planted by National forests, the Bureau of Land Management, and others. In addition, pines with some resistance to white pine blister rust are also under development. The Dorena Center offers expert advice to various partners engaged in resistance-breeding for Oregon’s ash trees and two tree species in Hawai`i, koa and ʻōhiʻa. and blog.

The USFS research program is well funded at $317 million. Unfortunately, only a tiny percentage of this research budget has been allocated to improving managers’ understanding of specific invasive species and, more generally, of the factors contributing to bioinvasions. Funding for research conducted by USFS Research stations on ten non-native pests decreased from $10 million in Fiscal Year 2010 to just $2.5 million in Fiscal Year 2020 – less than 1% of the total research budget. This cut of more than 70% has crippled the USFS’ ability to develop effective tools to manage the growing number of pests.

To ensure the future health of America’s forests, please ask your Member of Congress and Senators to request the Subcommittee to include in its report instructions that USFS increase the funding for this vital research area to 5% of the total research budget. The $16 million would fund research necessary to improving managers’ understanding of invasive forest insects’ and pathogens’ invasion pathways and impacts, as well as to developing effective management strategies. Addressing these threats is vital to supporting the Administration’s priorities of increasing adaptation and resilience to climate change and implementing nature-based solutions.

The USFS Research and Development program should expand its contribution to efforts to breed trees resistant to non-native pests; programs deserving additional funding include hemlocks resistant to hemlock woolly adelgid; ashes resistant to emerald ash borer; beech resistant to both beech bark disease and beech leaf disease; link to DMF and elms resistant to Dutch elm disease. The Research program also continues studies to understand the epidemiology of laurel wilt disease, which has spread to sassafras trees in Kentucky and Virginia.

Members of House Appropriations Committee

STATE	MEMBER	APHIS APPROP	USFS APPROP
AL	Robert Aderholt	X
Calif	Barbara Lee David Valadao Josh Harder	X X	X
FL	Debbie Wasserman Scultz	X
GA	Sanford Bishop	X
ID	Mike Simpson		X
IL	Lauren Underwood	X
MD	Andy Harris	X
ME	Chellie Pingree	X	X
MI	John Moolenaar	X
MN	Betty McCollum	X	X
NV	Susie Lee Mark Amodei		X X
NY	Grace Meng	X
OH	Marcy Kaptur David Joyce		X X
PA	Matt Cartwright		X
TX	Henry Cuellar	X
UT	Chris Stewart		X
WA	Dan Newhouse Derek Kilmer	X	X
WI	Mark Pocan	X

Members of Senate Appropriations Committee

STATE	MEMBER	APHIS APPROP	USFS APPROP
AK	Lisa Murkowski		X
Calif	Diane Feinstein	X	X
FL	Marco Rubio		X
HI	Brian Schatz	X
IN	Mike Braun	X
KS	Jerry Moran	X
KY	Mitch McConnell	X	X
MD	Chris Van Hollen		X
ME	Susan Collins	X
MS	Cindy Hyde-Smith	X	X
MO	Roy Blunt	X	X
MT	Jon Tester	X	X
ND	John Hoeven	X
NM	Martin Heinrich	X	X
OR	Jeff Merkley	X	X
RI	Jack Reed		X
TN	Bill Hagerty		X
VT	Patrick Leahy	X	X
WV	Shelly Moore Capito		X
WI	Tammy Baldwin	X

Posted by Faith Campbell

SOD – Frightening Genetics

tanoak killed by SOD; photo by Joseph O’Brien, via Bugwood

I am belatedly catching up with developments regarding sudden oak death (SOD; Phytophthora ramorum). The situation is worsening, with three of the four existing strains now established in U.S. forests. Nursery outbreaks remain disturbingly frequent.

This information comes primarily from the California Oak Mortality Task Force’s (COMTF) newsletters posted since October; dates of specific newsletters are shown in brackets.

Alarming presence of variants & hybridization

The long-feared risk of hybridization among strains has occurred. Canadian authorities carrying out inspections of a British Columbia nursery found a hybrid of European (EU1) and North American (NA2) clonal lineages. These hybrids are viable, can infect plants and produce spores for not only long-term survival but also propagation. So far the hybrid has been found in a single nursery; it has not spread to natural forests. The pathogen is considered eradicated in that nursery, so it is hoped it cannot reproduce further. [December 2021 newsletter, summarizing research by R. Hamelin et al.]

Noted British forest pathologist Clive Brasier warned in 2008 about the risk of hybrids evolving in nurseries which harbor multiple strains of related pathogens. (See full citation at end of the blog.)

The threat is clear: three of the four known variants are already established in forests of the Pacific Northwest – NA1, NA2, and EU1. (For an explanation of P. ramorum strains and mating types, go here.)

In Oregon, the EU1 strain was detected in a dying tanoak (Notholithocarpus densiflorus) tree in the forests of Curry County in 2015. Genetic analysis revealed that the forest EU1 isolates were nearly identical to EU1 isolates collected in 2012 from a nearby nursery during routine monitoring. This detection was considered to be evidence that multiple distinct P. ramorum introductions had occurred. The scientists expressed concern that the presence of this strain – which is of the A1 mating type while the widely established NA1 population of the pathogen in the forest is of the A2 mating type — makes the potential for sexual recombination more likely. Therefore, the state prioritized eradication of the EU1 forest infestation [Grünwald et al. 2016]. (For an explanation of P. ramorum strains and mating types, go here.)

The NA2 strain was detected in 2021, 33 km north of the closest known P. ramorum infestation. Because Oregonians genotype all detections on the leading front of the infection, they completed Koch’s postulates and found this surprising result [February 2022]. NA2 is thought to be more aggressive than the NA1 lineage [February 2022]. Surveys and sampling quickly determined that the outbreak is well established — 154 positive detections [February 2022] across more than 500 acres [October 2021]. Oregon Department of Forestry immediately began treatments; the goal is to prevent overlap with existing NA1 and EU1 populations. [April 2022; summarizing research by Peterson et al.] Given the number of infected trees and the new variant, Oregon pathologists believe this to be a separate introduction to Oregon forests that has been spreading in the area for at least four years [February 2022].

Scientists [April 2022; summarizing research by Peterson et al.] again note evidence of repeated introductions of novel lineages into the western US native plant communities; this region is highly vulnerable to Phytophthora establishment, justifying continued monitoring for P. ramorum not only in nurseries but also in forests.

SOD in Oregon; photo by Oregon Department of Forestry

The EU1 strain is also present in northern California, specifically in Del Norte County. It was detected there in 2020. Despite removal of infected and nearby host trees (tanoaks) and treatment with herbicide to prevent resprouting, the EU1 strain was again detected on tanoaks in 2021. The detected strain is genetically consistent with the EU1 outbreak in Oregon forests. Oddly, the usual strain found in North American forests, the NA1 strain, was not detected in Del Norte Co. in 2021 [February 2022].

One encouraging research finding [April 2022; summarizing research by Daniels, Navarro, and LeBoldus] is that established treatment measures have had significant impact on both the NA1 & EU1 lineages. They found on average 33% fewer positive samples at treated sites where NA1 is established; 43% reduction in P. ramorum prevalence at EU1 sites. Prevalence of P. ramorum in soil was not affected by treatment.

SOD Spread in Forests

In California, the incidence of new Phytophthora ramorum infections fell in 2021 to a historic low – estimated 97,000 dead trees across 16,000 acres, compared to ~885,000 dead trees across 92,000 acres in 2019 [April 2022]. It is agreed that the reason is the wave of mortality sparked by the very wet 2016-2017 winter has subsided and has been followed by several years of drought [February 2022].

data showing decline in new SOD detections in California in 2021 (no data collected in 2020)

In Oregon, however, SOD continues to spread. In 2010, the OR SOD Program had conceded that eradication was no longer feasible. Instead, authorities created a Generally Infested Area (GIA) where removal of infested tanoaks was now optional (not mandated) on private and state-owned lands. Since then, SOD has continued to spread and intensify within the designated zone. The GIA has been expanded eight times since its establishment in 2012; it now it covers 123 sq. mi. There has also been an immediate increase in tanoak mortality [December 2021].

In 2021, two new infestations were detected outside the GIA. One outbreak is on the Rogue River-Siskiyou National Forest along the Rogue River, 6 miles north of any previously known infestation. The second is just outside Port Orford [February 2022], 33 km north of the closest known infestation. This second infestation is composed of the NA2 variant [see above]. The Oregon Department of Agriculture (ODA) established emergency quarantines at these sites and began eradication efforts at both sites. The Oregon legislature appropriated $1.7 million to Oregon Department of Forestry to carry out an integrated pest management program to slow spread of the disease [February 2022].

Scientific research indicates that this situation might get worse. While it has long been recognized that California bay laurel (= Oregon myrtle) (Umbellularia californica) and tanoak are the principal hosts supporting sporulation and spread, it has now been determined that many other native species in the forest can support sporulation. Chlamydospore production was highest on bigleaf maple (Acer macrophyllum)and hairyCeanothus (Ceanothus oliganthus). All the other hosts produced significantly fewer spores than tanoak and myrtle [October 2021; summarizing research by Rosenthal, Fajardo, and Rizzo]

Furthermore, studies that aggregate observations of disease on all hosts, not paying attention to their varying levels of susceptibility, might lead scientists to misinterpret whether the botanic diversity slows spread of the pathogen [October 2021 summarizing research by Rosenthal, Simler-Williamson, and Rizzo].

Monitoring to detect any possible spread to the East

SOD risk map based on climate & presence of host species; USFS

The USDA Forest Service continues its Cooperative Sudden Oak Death Early Detection Stream Survey in the East. In 2021, 12 states participated – Alabama, Florida, Georgia, Illinois, Maryland, Mississippi, North Carolina, Pennsylvania, South Carolina, Texas, West Virginia, and Wisconsin. Samples were collected from 79 streams in the spring. Two streams were positive, both in Alabama. Both are associated with nurseries that were positive for P. ramorum more than a decade ago [October 2021].

Continued infestations in the nurseries

USDA Animal and Plant Health Inspection Service (APHIS) reported that in 2021, the agency supported compliance activities, diagnostics, and surveys in nurseries in 22 states. P. ramorum was detected at 17 establishments. Eight were new; nine had been positive previously. These included seven nurseries that ship intrastate – all had been positive previously. Six were already under compliance agreements. Also positive were three big box stores – none previously infected; and six nurseries that sell only within one state – five new. Infections at the big box outlets and half the intrastate nurseries were detected as a result of trace-forwards from other nurseries.

P. ramorum was detected in 300 samples in 2021 – 144 from plants in the genus Viburnum; 106 from Rhodendron (including azalea); and much lower numbers from other genera.

APHIS funds states for annual nursery surveys, compliance activities, and diagnostics through the: Plant Protection Act Section 7721 and the Cooperative Agricultural Pest Survey (CAPS) program. Table 4 lists states receiving survey funds. APHIS also supported compliance and diagnostic activities in California, Louisiana, Oklahoma, Oregon, Pennsylvania, Washington, and several states through Florida.

APHIS’ report – which provides few additional details about the nursery detections – can be found here.

California:

The California Department of Food and Agriculture (CDFA) reported that three of the eight nurseries regulated under either the federal or state sudden oak death program tested positive in 2021. This was down from five positive nurseries in 2020 [February 2022]. (In the past, numbers of nurseries testing positive have declined during droughts, risen during wet years.) At one interstate-shipping nursery 145 positive Viburnum tinus plants were detected by regulators in December 2021. Apparently the detection efforts were prompted by a trace-back from a nursery in an (unnamed) other state [April 2022].

Oregon:

Oregon continues to struggle with the presence of Phytopththora ramorum in the state’s nurseries. Early in 2021 the situation looked good. Three of eight interstate shippers and two intrastate shippers “passed” their sixth consecutive inspection with no P. ramorum detected so they were released from state and federal program inspection requirements. A fourth interstate-shipping nursery had ceased operating. By the end of the year, however, circumstances had deteriorated. One of the four interstate shippers still under regulatory scrutiny appeared to be badly infested. After routine autumn monitoring detected an infected plant, subsequent delimitation samplings detected 30 additional positive foliar samples and a large number (24) of samples were inconclusive. By spring 2022 six nurseries had to be inspected following trace-forwards from out-of-state nurseries. No P. ramorum was detected in five of these nurseries; the sixth had one positive foliar sample, so it is now under more stringent regulatory supervision [April 2022].

Washington:

Washington has only one interstate shipping nursery that is regulated under APHIS’ program; it tested negative in autumn 2021 [December 2021]. Meanwhile, USDA & Washington Department of Agriculture (WSDA) decided to deregulate the Kitsap County Botanical Garden where P. ramorum had been detected in 2015. Since then, more than 5,000 samples have been collected; 99.1% have tested negative. The last positive plant sample was collected in February 2016. Under a compliance agreement, the botanical garden will continue the best management practices deemed successful in eradicating the pathogen [December 2021]. However, water at the site continues to test positive [February 2022]. These water detections – in Washington and Alabama (above) – raise troubling questions.

Meanwhile, in late winter [April 2022], WSDA had to conduct two trace-forward investigations on plants that shipped from (unnamed) out-of-state nurseries. As of the April newsletter, 13 samples from four locations were all negative.

A stubborn problem has been the persistence of SOD infections in nurseries after the Confirmed Nursery Protocol has been carried out. Research indicates the reason might be that the pathogen is still there in the form of soilborne inoculum in buried, infested leaf debris [December 2021 newsletter; summarizing research by Peterson, Grünwald, and Parke].

Another native tree identified as host

Dieback on golden chinquapin, Chrysolepis chrysophylla, a slow growing, evergreen tree native to the U.S. west coast has been confirmed as caused by Phytophthora ramorum. The detection was in a part of Marin County, California heavily infested by P. ramorum since early in the epidemic. Affected trees were large overstory trees. Unlike other hosts in the Fagaceae, there were no external bole cankers [April 2022 newsletter; summarizing research by Rooney-Latham, Blomquist, Soriano, and Pastalka].

SOURCES

Brasier, C.M. 2008. The biosecurity threat to the UK and global environment from international trade in plants. Plant Pathology (2008) 57, 792-808

Grunwald, N.J., M.M. Larsen, Z.N. Kamvar, P.W. Reeser, A. Kanaskie, J. Laine and R. Wiese. 2016. First Report of the EU1 Clonal Lineage of Phytophthora ramorum on Tanoak in an Oregon Forest. Disease Notes. May 2016, Vol. 100, No. 5, p. 1024

Posted by Faith Campbell

What Do Invasive Species Cost?

brown tree snake *Boiga irregularis*; via Wikimedia; one of the species on which the most money is spent on preventive efforts

In recent years a group of scientists have attempted to determine how much invasive species are costing worldwide. See Daigne et al. 2020 here.

Some of these scientists have now gone further in evaluating these data. Cuthbert et al. (2022) [full citation at end of blog] see management of steadily increasing numbers of invasive, alien species as a major societal challenge for the 21st Century. They undertook their study of invasive species-related costs and expenditures because rising numbers and impacts of bioinvasions are placing growing pressure on the management of ecological and economic systems and they expect this burden to continue to rise (citing Seebens et al., 2021; full citation at end of blog).

They relied on a database of economic costs (InvaCost; see “methods” section of Cuthbert et al.) It is the best there is but Cuthbert et al. note several gaps:

Only 83 countries reported management costs; of those, only 24 reported costs specifically associated with pre-invasion (prevention) efforts.
Data comparing regional costs do not incorporate consideration of varying purchasing power of the reporting countries’ currencies.
Data available are patchy so global management costs are probably substantially underestimated. For example, forest insects and pathogens account for less than 1% of the records in the InvaCost database, but constitute 25% of total annual costs ($43.4 billion) (Williams et al., in prep.) .

Still, their findings fit widespread expectations.

These data point to a total cost associated with invasive species – including both realized damage and management costs – of about $1.5 trillion since 1960. North America and Oceania spent by far the greatest amount of all global money countering bioinvasions. North America spent 54% of the total expenditure of $95.3 billion; Oceania spent 30%. The remaining regions each spent less than $5 billion.

Cuthbert et al. set out to compare management expenditures to losses/damage; to compare management expenditures pre-invasion (prevention) to post-invasion (control); and to determine potential savings if management had been more timely.

Economic Data Show Global Efforts Could Be – But Aren’t — Cost-Effective

The authors conclude that countries are making insufficient investments in invasive species management — particularly preventive management. This failure is demonstrated by the fact thatreported management expenditures ($95.3 billion) are only 8% of total damage costs from invasions ($1.13 trillion). While both cost or losses and management expenditures have risen over time, even in recent decades, losses were more than ten times larger than reported management expenditures. This discrepancy was true across all regions except the Antarctic-Subantarctic. The discrepancy was especially noteworthy in Asia, where damages were 77-times higher than management expenditures.

Furthermore, only a tiny fraction of overall management spending goes to prevention. Of the $95.3 billion in total spending on management, only $2.8 billion – less than 3% – has been spent on pre-invasion management. Again, this pattern is true for all geographic regions except the Antarctic-Subantarctic. The divergence is greatest in Africa, where post-introduction control is funded at more than 1400 times preventive efforts. It is also significant for Asia and South America.

Even in North America – where preventative actions were most generously funded – post-introduction management is funded at 16 times that of prevention.

Cuthbert et al. worry particularly about the low level of funding for prevention in the Global South. They note that these conservation managers operate under severe budgetary constraints. At least some of the bioinvasion-caused losses suffered by resources under their stewardship could have been avoided if the invaders’ introduction and establishment had been successfully prevented.

While in the body of the article Cuthbert et al. seem uncertain about why funding for preventive actions is so low, in their conclusions they offer a convincing (to me) explanation. They note that people are intrinsically inclined to react when impact becomes apparent. It is therefore difficult to motivate proactive investment when impacts are seemingly absent in the short-term, incurred by other sectors, or in different regions, and when other demands on limited funds may seem more pressing. Plus efficient proactive management will prevent any impact, paradoxically undermining evidence of the value of this action!

*Aedes aegypti* mosquito; one of the species on which the most money is spent for post-introduction control; photo by James Gathany; via Flickr

Delay Costs Money

The reports contained in the InvaCost database indicate that management is delayed an average of 11 years after damage was first been reported. Cuthbert et al. estimate that these delays have caused an additional cost of about $1.2 trillion worldwide. Each $1 of management was estimated to reduce damage by $53.5 in this study. This finding, they argue, supports the value of timely invasive species management.

They point out that the Supplementary Materials contain many examples of bioinvasions that entail large and sustained late-stage expenditures that would have been avoided had management interventions begun earlier.

Although Cuthbert et al. are not as clear as I would wish, they seem to recognize also that stakeholders’ varying perceptions of whether an introduced species is causing a detrimental “impact” might also complicate reporting – not just whether any management action is taken

Cuthbert et al. are encouraged by two recent trends: growing investments in preventative actions and research, and shrinking delays in initiating management. However, these hopeful trends are unequal among the geographic regions.

Which Taxonomic Groups Get the Most Money?

About 42% of management costs ($39.9 billion) were spent on diverse or unspecified taxonomic groups. Of the costs that were taxonomically defined, 58% ($32.1 billion) was spent on invertebrates [see above re: forest pests]; 27% ($14.8 billion) on plants; 12% ($6.7 billion) on vertebrates; and 3% ($1.8 billion) on “other” taxa, i.e. fungi, chromists, and pathogens. For all of these defined taxonomic groups, post-invasion management dominated over pre-invasion management.

When considering the invaded habitats, 69% of overall management spending was on terrestrial species ($66.1 billion); 7% on semi-aquatic species ($6.7 billion); 2% on aquatic species ($2.0 billion); the remainder was “diverse/unspecified”. For pre-invasion management (prevention programs), terrestrial species were still highest ($840.4 million). However, a relatively large share of investments was allocated to aquatic invaders ($624.2 million).

Considering costs attributed to individual species, the top 10 targetted for preventive efforts were four insects, three mammals, two reptiles, and one alga. Top expenditures for post-invasion investments went to eight insects [including Asian longhorned beetle], one mammal, and one bird.

Asian longhorned beetle

Just two of the costliest species were in both categories: insects red imported fire ant(Solenopsis invicta) and Mediterranean fruitfly (Ceratitis capitate). None of the species with the highest pre-invasion investment was among the top 10 costliest invaders in terms of damages. However, note the lack of data on fungi, chromists, and pathogens. (I wrote about this problem in an earlier blog.)

Discussion and Recommendations

Cuthbert et al. conclude that damage costs and post-invasion spending are probably growing substantially faster than pre-invasion investment. Therefore, they call for a stronger commitment to enhancing biosecurity and for more reliance on regional efforts rather than ones by individual countries. Their examples of opportunities come from Europe.

Drawing parallels to climate action, the authors also call for greater emphasis on during decision-making to act collectively and proactively to solve a growing global and inter-generational problem.

Cuthbert et al. focus many of their recommendations on improving reporting. One point I found particularly interesting: given the uneven and rapidly changing nature of invasive species data, they think it likely that future invasions could involve a new suite of geographic origins, pathways or vectors, taxonomic groups, and habitats. These could require different management approaches than those in use today.

As regards data and reporting, Cuthbert et al. recommend:

1) reducing bias in cost data by increasing funding for reporting of underreported taxa and regions;

2) addressing ambiguities in data by adopting a harmonized framework for reporting expenditures. For example, agriculture and public health officials refer to “pest species” without differentiating introduced from native species. (An earlier blog also discussed the challenge arising from these fields’ different purposes and cultures.)

3) urging colleagues to try harder to collect and integrate cost information, especially across sectors;

4) urging countries to report separately costs and expenditures associated with different categories, i.e., prevention separately from post-invasion management; damage separately from management efforts; and.

5) creating a formal repository for information about the efficacy of management expenditures.

While the InvaCost database is incomplete (a result of poor accounting by the countries, not lack of effort by the compilers!), analysis of these data points to some obvious ways to improve global efforts to contain bioinvasion. I hope countries will adjust their efforts based on these findings.

SOURCE

Cuthbert, R.N., C. Diagne, E.J. Hudgins, A. Turbelin, D.A. Ahmed, C. Albert, T.W. Bodey, E. Briski, F. Essl, P. J. Haubrock, R.E. Gozlan, N. Kirichenko, M. Kourantidou, A.M. Kramer, F. Courchamp. 2022. Bioinvasion costs reveal insufficient proactive management worldwide. Science of The Total Environment Volume 819, 1 May 2022, 153404

Seebens, H. S. Bacher, T.M. Blackburn, C. Capinha, W. Dawson, S. Dullinger, P. Genovesi, P.E. Hulme, M.van Kleunen, I. Kühn, J.M. Jeschke, B. Lenzner, A.M. Liebhold, Z. Pattison, J. Perg, P. Pyšek, M. Winter, F. Essl. 2021. Projecting the continental accumulation of alien species through to 2050. Glob Change Biol. 2021;27:970-982.

Williams, G.M., M.D. Ginzel, Z. Ma, D.C. Adams, F.T. Campbell, G.M. Lovett, M. Belén Pildain, K.F. Raffa, K.J.K. Gandhi, A. Santini, R.A. Sniezko, M.J. Wingfield, and P. Bonello 2022. The Global Forest Health Crisis: A Public Good Social Dilemma in Need of International Collective Action. submitted

Posted by Faith Campbell

Reminder: ask your MC & Senators to sponsor tree-restoration bill!

The Invasive Species Prevention and Forest Restoration Act (H.R. 1389) is before Congress. It is co-sponsored by Reps. Peter Welch [VT], Ann Kuster and Chris Pappas [NH], Chellie Pingree [ME], Elise Stefanik and Antonio Delgado [NY], Brian Fitzpatrick [PA], Mike Thompson [CA], Deborah Ross [NC].

Ask your Member of Congress/Representative to co-sponsor this bill. Ask your Senators to sponsor a companion bill.

In summary, this bill will:

Expand USDA APHIS’ access to emergency funds to eradicate or contain newly detected pest outbreaks.
Establish a pair of grant programs to support strategies aimed at restoring tree species decimated by non-native plant pests or noxious weeds. Such strategies include biological control of pests and enhancement of a tree host’s pest resistance.
1. One grant program supports research to explore and develop these strategies.
2. The second program support application of resistance breeding and other measures to restore forest tree species. Funded programs must incorporate a majority of the following components: collection and conservation of native tree genetic material; production of sufficient numbers of propagules; preparation of planting sites in the species’ former habitat; planting and post-planting maintenance.
Mandate a study to identify actions to overcome the shortfall of mission, leadership, and prioritization; identify agencies’ expertise and resources; improve coordination among agencies and with partners; and develop national strategies for saving tree species.

Organizations eligible for these grants include federal agencies; state cooperative institutions; colleges or universities offering a degree in the study of food, forestry, and agricultural sciences; and nonprofit entities with non-profit status per §501(c)(3) of the Internal Revenue Code.

Endorsements: Vermont Woodlands Association, American Forest Foundation, The Association of Consulting Foresters (ACF), Audubon Vermont, Center for Invasive Species Prevention, Ecological Society of America, Entomological Society of America, Maine Woodland Owners Association, Massachusetts Forest Alliance, National Association of State Foresters (NASF), National Woodland Owners Association (NWOA), The Nature Conservancy (TNC) Vermont, New Hampshire Timberland Owners Association, North American Invasive Species Management Association (NAISMA), Pennsylvania Forestry Association, Reduce Risk from Invasive Species Coalition, The Society of American Foresters (SAF), and a broad group of university professors and scientists.

Legislative Point of Contact: Alex Piper, Legislative Assistant, office of Rep. Welch. Contact me – providing your email! – if you wish me to send you Alex’ contact information. [The “contact” form does not provide your email and I will not reply in a public way.]

Posted by Faith Campbell

Interactions of 2 (of 3) Threats to Beech

American beech (Fagus grandifolia) is a widespread and beautiful tree of the eastern deciduous forest. Its range reaches from Nova Scotia to eastern Wisconsin, then south to Mississippi and Louisiana and east to mid-Georgia. It is an important food source for 40 wildlife species, particularly in the northern parts of its range where few other species produce hard mast. (See Lovett et al. 2006.)

Threats

Unfortunately American beech is under threat from three non-native organisms or complexes: 1) beech bark disease, 2) beech leaf disease, and 3) beech leaf mining weevil. A fourth pest, a previously unknown – and still unnamed bark beetle in the genus Agrilus – has been detected in New York City on European beech trees. It is not yet known whether it will attack American beech and, if so, whether it will also cause serious damage (Michael Bohne, USFS, pers. comm.)

symptoms of beech bark disease; photo by Linda Haugen, USFS; via Bugwood

Beech bark disease (BBD) results from the interaction of the introduced European beech scale insect (Cryptococcus fagisuga) and several fungi in the Neonectria genus – some of which are also introduced. The resulting disease has been killing American beech trees since the beginning of the 20^th Century. It has spread from Nova Scotia to much of the tree’s range. It has dramatically altered the composition and structure of stands containing beech.

symptoms of beech leaf disease; photo provided by Jennifer Koch, USFS

Beech leaf disease (BLD) was initially detected in 2012, near Cleveland. As of December, 2021, it has spread due east across New York, Pennsylvania, and New Jersey to the Atlantic, then up the coast through Connecticut and eastern Massachusetts, with a separate outbreak in central Maine. The disease is apparently associated with a nematode, Litylenchus crenatae ssp. mccanni, although additional pathogens, like bacteria, might also play a role. The origin of the North American population of the nematode is unknown; it is a related but separate subspecies from a Japanese nematode (Reed et al. 2022).

American beech defoliated by leaf mining weevil; photo courtesy of Jon Sweeney, CFS

Beech leaf mining weevil (Orchestes fagi) is, so far, limited to Nova Scotia. However, it is expected that the weevil will continue spreading throughout the range of American beech through both natural dispersal and human-assisted movement. Repeated defoliation by the weevil might increases mortality rates in forests that are surviving in the “aftermath” stage of BBD (Sweeney et al. 2020).

A new study (Reed et al. 2022) concludes that, despite being detected only 10 years ago, BLD has already become pervasive in forests surrounding Lake Erie in the U.S. and Ontario. While somewhat more prevalent in U.S. states on the eastern side of the Great Lakes (on 54% of trees) than in Ontario (on 46% of trees), BLD is spreading rapidly and affecting every canopy layer. Mortality is highest in seedlings and saplings; understory saplings die within 2 – 5 years. The occasional mortality of overstory trees occurs within seven years of [observed] infection. Defoliation and mortality of saplings allow more light to pass through to the understory; this is expected to alter plant communities on the forest floor.

Beech scale is more widespread in Ontario (found on 60% of trees) than in the U.S. (38% of trees). This is not surprising since the scale was detected in Ontario in 1960, 24 years before it was detected in portions of Ohio, New York and Pennsylvania included in the study (in 1984). Throughout this region, beech scale is disproportionately affecting overstory trees.

Only 4% of trees throughout the study area are infected with Neonectria cankers. In other words, full-scale beech bark disease is not yet widespread and is spreading surprisingly slowly. Scientists do not understand this phenomenon.

These findings are based on a network of monitoring plots a network of monitoring plots set up in 2019 set up in areas surrounding the Great Lakes. They comprise 34 plots at 17 locations in southwest Ontario and 30 plots at 25 locations in Ohio, Pennsylvania, and New York. In total the plots hold 646 live American beech trees — 412 saplings; 85 in the intermediate/suppressed (subcanopy) category; and 149 in the dominant/codominant (canopy) class.

Forest composition is similar throughout the study area. The most common species in association with American beech are sugar and red maples (Acer spp.), and white and green ash (Fraxinus spp.). Other tree species present include eastern hemlock (Tsuga canadensis), white pine (Pinus strobus), oaks (Quercus spp.), and birches (Betula spp.). Study plots had few invasive plants – although the invasive species present are well-documented to invade forests.

Ontario disease assessment

In Ontario, BLD was identified in 25 of the 34 plots. It was present on 171 saplings, 53 intermediate trees, and 70 dominant trees. Both prevalence and severity were greatest on intermediate trees. Beech scale was present at all 34 plots. While scales were found on trees of all sizes, they were almost two times more prevalent and were more severe on mature trees than saplings. Neonectria cankers were detected at 34 plots. Neonectria was rare but most severe on dominant trees. Fewer than one third of saplings and one-sixth of mature trees were pest free.

U.S. disease assessment

BLD was present in 17 of the 30 plots. It was found on 75 saplings, 30 intermediate trees, and 38 dominant trees. Saplings and dominant trees had similar levels of disease; intermediate trees had significantly less. However, BLD severity was twice as high on saplings compared to mature trees. BLD was present on more than half of the seedlings assessed – 46 out of 82. Beech scale was present in 20 of the 30 plots. It was significantly less common and severe on saplings than on mature trees. Neonectria cankers were present in only 4 of 30 plots. Canker prevalence and severity did not differ significantly among size classes.

Distribution and Effects of Beech Scale and BBD

While beech scale attack facilitates invasion by the Neonectria fungi, the disease – BBD complex – had the most limited distribution of the three pests in this study. It was found on only ~4% of beech trees throughout the study area. The disease was first reported there in the early 2000s. Although no one knows why, it has spread more slowly there than in areas to the east (Reed et al. 2022).

As is the case with beech scale, BBD disproportionately affects large diameter trees. Typically, BBD kills more than half of mature beech within 10 years of its arrival. Dying trees produce prolific root sprouts resulting in dense beech sapling understories that impede regeneration of less shade-tolerant tree species. The persistence of thickets of disease-vulnerable small beech perpetuates the disease. BBD is the only forest disease in North America that can inadvertently intensify itself by increasing densities of its host while suppressing other species.

Beech Forest Community Change in Response to Combined Impacts of BBD and BLD

It is unclear how forests will change as beech die. Some expect saplings of species already present — red maple, white ash, and, especially sugar maple — to exploit the canopy gaps. Of course, white and green ash are under attack by the emerald ash borer; DMF their ability to reach the canopy will depend on the success of biocontrol agents.

However, if BBD or BLD resistant beech survive or if BLD fails to persist, future forests might instead consist of beech thickets that would prevent all but the most shade tolerant species from establishing. Heavy deer predation on maple seedlings and saplings might also play a role. A third possibility is that morbidity from BBD and BLD might lead to uneven-aged conditions that allow younger trees — perhaps even shade intolerant species e.g., oaks — to establish.

Invasive plants also have the potential to fill gaps left by declining beech. While maple-beech forests often have sparse understories due to low understory light levels, pest-caused canopy gaps are expected to increase the abundance of invaders, especially in small woodlots and forests near urban areas. Several shade-tolerant invasive shrubs are already present in low numbers: Japanese barberry (Berberis thunbergii), tatarian honeysuckle (Lonicera tatarica), multiflora rose (Rosa multiflora), and buckthorn (Frangula sp.). Reed et al. (2022) note that these species, plus privet and autumn olive, can take advantage of small canopy gaps, especially when soils are disturbed, e.g., by active intervention to counteract the loss of beech.

Precautionary Research and Management

Reed et al. (2022) call for enhanced monitoring of beech forests focused on

the timing of BLD presence relative to tree age and size – which might affect competitiveness of sprouting beech in the understory; and
compositional and structural change in forests with BLD or to which it is likely to spread

They also recommend abandoning the management approach for BBD currently recommended by foresters. It calls for removing scale-susceptible beech so that resistant genotypes increase in prevalence. In forests with both BBD and BLD, they conclude, management of natural regeneration is unlikely to succeed because BLD will kill sprouts and saplings that might be resistant to scale. They recommend instead active management of the forest to promote mast-producing, shade intolerant species, such as oaks and hickories.

They also recommend increased support for resistance-breeding programs. Such programs already target BBD, based on the estimated 1% of American beech that show some resistance. Now those programs need to incorporate BLD resistance. (Reed et al. note that small numbers of beech show few or no BLD symptoms so might possess resistance or tolerance.)

grafted beech for resistance breeding; photo by Rachel Kappler, then USFS (now Great Lakes Basin Initiative & Holden Arboretum)

Unfortunately, the Canadian beech breeding program’s future funding is highly uncertain. To counter this threat, in part, Reed et al. (2022) suggest cryopreserving beech embryos from Canada to develop a beech conservation collection that would be available for a more robust, future Canadian breeding program. The USFS is trying to develop methods to screen trees for resistance to BLD, specifically to the nematode (J. Koch, USFS, pers. comm.)

Another approach would actively manage beech stands in which potentially BLD-resistant beech grow to help these trees reach the canopy and reproduce. In the absence of management, any BLD-resistant beech seedlings might be overtopped by faster growing, shade-intolerant species – especially if the gaps promote soil drying or sun scald.

Finally, breeding programs need to factor in the beech leaf mining weevil, DMF which — as I noted in the beginning — is spreading across Nova Scotia and could spread to the rest of the native range of beech (Sweeney et al., 2020).

The Department of Agriculture has created a website on the Department’s plant-breeding efforts. It includes a subwebsite on USFS efforts. However, I did not find much useful information there.

SOURCES

Lovett, G.M., C.D. Canham, M.A. Arthur, K.C. Weathers, and R.D. Fitzhugh. 2006. Forest Ecosystem Responses to Exotic Pests and Pathogens in Eastern North America. BioScience Vol. 56 No. 5 May 2006)

Reed, S.F., D. Volk, D.K.H. Martin, C.E. Hausman, T. Macy, T. Tomon, S. Cousins. 2022. The distribution of beech leaf disease and the causal agents of beech bark disease (Cryptoccocus fagisuga, Neonectria faginata, N. ditissima) in forests surrounding Lake Erie and future implications Forest Ecology and Management 503 (2022) 119753

Sweeney J.D., Hughes, C., Zhang, H., Hillier, N.K., Morrison, A. and Johns R. (2020) Impact of the Invasive Beech Leaf-Mining Weevil, Orchestes fagi, on American Beech in Nova Scotia, Canada. Frontiers in Forests and Global Change | www.frontiersin.org 1 April 2020 | Volume 3 | Article 46

Posted by Faith Campbell