forest pest insects – Page 4 – Center for Invasive Species Prevention

Y’all Come! National Plant Board Will Meet in Virginia in July 2026

The National Plant Board (NPB) represents the state officials responsible for preventing the introduction, establishment, and spread of invasive species called “plant pests” – including insects and pathogens that attack our native flora and invasive plants. The NPB has just held its 2025 meeting, on which I report here.

Coming to the Mid-Atlantic: NPB 2026 Annual Meeting

The next annual meeting will be in Alexandria, Virginia at the end of July 2026.I have attended these annual meetings since 2006 and always find them worth my time. They provide a wonderful opportunity to interact with the state and federal officials responsible for managing invasive plants and plant pests, and to assess regulatory issues. Contact me for more information.

The agendas focus on practical topics, such as science and technology tools, changes in APHIS policies or practices, and progress in cooperation among relevant federal agencies (i.e., the U.S. Department of Agriculture and the Department of Homeland Security’s Bureau of Border Protection) and with the states. While agricultural pest issues are stressed, tree-killing pests also get attention. Sometimes invasive plants are also discussed. The Board’s state representatives seek ways to coordinate their efforts both at these meetings and throughout the year.

Issues in the host location are part of the focus. Next year, that will be the Mid-Atlantic. The meeting is being co-hosted by the departments of Agriculture of Virginia, Maryland, Washington, D.C., and Delaware.

I expect that there will be opportunities for presenting concerns of non-governmental organizations – at least through staffed display tables and possibly other activities. I hope the many conservation organizations that have a Washington, D.C., presence will consider participating.

In Honolulu: NPB 2025 Annual Meeting

NPB’s 2025 Annual Meeting in Honolulu focused to some extent on the unique aspects of agriculture and introduced pests on remote Pacific islands. (Guam was co-host.) This blog reports on current efforts by federal and state authorities to counter bioinvasions there and around the country.

I took advantage of the meeting to visit the “Big Island” of Hawai`i to see for myself the impact of rapid ‘ōhi‘a death and enjoy the native flora (for example, the hapu tree fern – below). I posted another blog reporting what I learned there.

native Hawaiian tree ferns & ʻōhiʻa; photo by F.T. Campbell

Federal

In an earlier blog, I outlined the Administration’s proposed cuts to staff of the U.S. Department of Agriculture (USDA) and contradictory actions by Congress in the annual appropriations bills.

As that blog makes clear, the work of USDA’s Animal and Plant Health Inspection Service (APHIS) is viewed much more positively by the Trump Administration than is the USDA Forest Service. While APHIS’ funding is much more secure, staff cuts and reorganization of the USDA still have caused setbacks. APHIS is expected to lose 15% of employees – 1,180 people. Four hundred APHIS employees accepted the Administration’s deferred resignation offer. These included the leadership of many programs – including the previous Deputy Administrator, Mark Davidson. Higher up, no one has been appointed to the position of Deputy Secretary for Marketing and Regulatory Affairs.

In his report to the meeting, APHIS Acting Deputy Administrator for Plant Protection and Quarantine Matthew Rhoads noted that the Administration’s Farm Security Plan, which emphasizes efforts to combat bioterrorism, includes APHIS’ safeguarding role. However, abrupt and incomplete leadership changes hamper efforts to replace those who have left and set agency priorities. While I am cheered by the reported priority for preventing pest introductions, I fear that the focus might be quite narrow, leaving out threats to natural resources such as native forest trees.

Rhoads announced that after years of effort, the Asian longhorned beetle has been declared eradicated on 12.3 square miles of the Massachusetts quarantine zone.

Much of the presentation by Matthew Rhoads and later ones by other APHIS staff updated attendees on progress on technologies important in pest detection and control, and specific projects being carried out jointly by APHIS and NPB members (that is, state regulatory officials chosen to represent the state phytosanitary agencies). I consider the collaborative projects — begun in February 2023 – to be very important. Twenty years ago, relations between APHIS and its state counterparts were characterized by an “us vs. them” attitude.

I will summarize progress on the projects of greatest interest to those of us focused on non-native insects and disease pathogens threatening tree species. Rhodes mentioned improvements in the plant pathogen diagnostic certification program and development of improved molecular diagnostics for 45 insects and plant pathogens, including several Phytophthora species.

Joint APHIS-NPB teams have completed many risk analyses: 18 datasheets, 20 assessments, and four pathway analyses. As usual, insects – especially beetles – are the most numerous taxa detected. Many were surprised that the majority of new detections occurred in the south. When he was asked about this, Rhoads speculated that this reflected the region’s more hospitable climate and Florida’s surveillance efforts. I noted that ports in the southeast – e.g., Savannah and Charleston – are receiving higher import volumes; and that there have been problems with dunnage in the port of Houston.

Large container ship docked at Port of Savannah; photo by F.T. Campbell

Rhoads praised the federal-state strategic alliance’s project targetting illegal importation of plants purchased on-line. His example should concern us: importation of as many as 10,000 black pine seedlings to Georgia. The state stopped sale of these plants and APHIS’ investigatory unit began an investigation. This example illustrates the volume of plants that might be moving in this trade. Several states asked APHIS to offer more help in countering trafficking involving smaller numbers. All agree that no one has yet figured out an effective way to control this pathway.

A second example of successful coordination between APHIS and the states was said to be the decision to not regulate Phytophthora austrocedri, a pathogen detected in several nurseries in Oregon in 2024. Possible hosts in the Pacific Northwest include the already-depleted Port Orford cedar, and here; Juniperus californica, J. grandis, J. occidentalis, and J. maritima. Federal and state plant health officials, in coordination with the nursery industry trade association (AmericanHort), reached this decision after determining that the pathogen has probably been present in Oregon for many years and been spread to other states on the large volumes of host plants shipped. Now it will be up to states and non-governmental conservation organizations to try to detect whether this pathogen has established and devise management strategies.

New Information (as of December 2025): someone has posted on the web a written explanation of this decision by APHIS to the National Plant Board. [Visit cdn.ymaws.com, search for “Phytopthora austro”]. APHIS estimated that delimitation surveys in just one nursery would cost more than $9 million. Because the pathogen cannot be detected by visual symptoms, even tracking spread requires expensive destructive sampling of large numbers of plants. Meanwhile, thousands of possibly infected plants have been shipped from at least two Oregon nurseries in recent years. APHIS concluded that a Federal survey program for P. austrocedri would not contribute to ultimately controlling the spread or eradication of this pathogen. The agency recommended instead that natural resource agencies adopt a “protective-style approach”, focused on actively managing highest-value natural sites.

Are federal, state, and non-governmental managers of the many types of ecosystems inhabited by junipers and cypresses equipped to do this?

Ordinarily, the USFS Forest Health Protection program would be in a position to assist states which want to manage this pest (assuming its establishment). But considering the current uncertainty regarding USFS’ future, blog states cannot count on that help.

Sky Stevens (entomologist on the staff of USFS Forest Health Protection program) reported on the situation at the USFS. She noted that the Congressional appropriations bills continue funding for the agency’s research program and collaboration with non-federal entities managing forests. Still, the USFS lost 5,200 people through “voluntary” resignations and firings.

The program of greatest importance to us, Forest Health, was cut from 18 people to 8. Stevens replaced the long-time national entomologist. The comparable pathologist has retired. Stevens is struggling to make decisions regarding the pathology program, especially since diseases are inherently more difficult. While the USFS is doing lateral exchanges to fill high-need vacancies, FHP has not yet been asked what the program needs.

According to Stevens, in 2024 about 9 million acres were impacted by forest pests. The FHP program treated 1 million acres. As usual, the (European) spongy moth was the largest target based on acreage. Other non-native species targetted were emerald ash borer, goldspotted oak borer, sudden oak death, Asian longhorned beetle, hemlock woolly adelgid, and rapid ‘ōhi‘a death. See summaries of these pests’ impacts and status here.

Continuation of these projects in 2025 often became trapped in the new Administration’s funding freezes; opportune times for effective actions were often missed. On-going projects include several targetting emerald ash borer and its hosts in Oregon and black ash swamps of the Midwest and Northeast; managing sudden oak death in Oregon and California; and delimitation surveys for rapid ‘ōhi‘a death. The SOD program benefits from approximately $3 million earmarked by Congress (out of the total funding for the forest health program of $48 million).

Stevens noted that it is difficult to discuss the program’s future given the uncertainty. Program staff hope to continue issuing products that help people understand forest health in their region – not limited to federal lands.

I learned from the review of the following programs and technical tools that many were funded by the grant program under APHIS’ Plant Pest and Disease Management and Disaster Prevention program (Plant Protection Act Section 7721). Clearly, America’s efforts to prevent and respond to invasions by plant pests (including invasive plants) would be far less robust without this grant program.

boxwood (box tree) garden at Gunston Hall – an 18th Century plantation near Alexandria, Virginia (site of the 2026 NPB meeting); Photo by Roger 4336 via Wikipedia

Wendy Jin, APHIS PPQ Associate Deputy Administrator, urged states to use pest forecast models developed under the SAFARIS program. These models incorporate information on weather; pest biology, environmental needs and impact; hosts; land cover; and relevant human activities. Fifty pests have been evaluated so far, apparently including Asian longhorned beetle, spongy moth, spotted lanternfly, and boxtree moth. (All but the last are described briefly under the “invasive species” tab here.) The goal is to provide managers information about the insect’s life stage at specific times in specific localities so that they can time their surveillance and management actions. However, I am somewhat worried because the models use current and historical weather data – which might not be pertinent as the climate warms. Worse, the modelers lack sufficiently detailed data to develop models for Alaska, Hawai`i, Puerto Rico, or Guam.

Dr. Carrie Harmon (Deputy Director, National Plant Diagnostic Network) described the resources available for states use from two diagnostics tools. Both were developed under grants which are now expiring. Therefore updates and further development will depend on renewal of the grants. The National Plant Diagnostic Network (NPDN) provides accurate data and alerts about appearances of plant diseases. APHIS is said to be collaborating closely to ensure as much data as possible is shared. A separate body, the Diagnostic Assay Validation Network, is validating diagnostic assays.

A few years ago the NPB and APHIS formalized their new level of collaboration as the “Strategic Alliance, Strategic Initiative”. The Plant Board surveyed its members to gauge their feelings about several issues: 1) data-sharing issues that impede decision-making; 2) ways to strengthen coordination when dealing with on-line sales of plants or other vectors of plant pests (see the pine-Georgia example above); and 3) what structures and practices could make resolving these problems easier.

One of the resulting initiatives is an analysis of implementation of the Federal Noxious Weed program in the absence of a line-item appropriation. However, the President’s “Department of Government Efficiency” (DOGE) prompted resignations and firings, including this project’s APHIS liaison. Without a replacement, it is unclear how the analysis can proceed.

Another speaker, representing Bob Baca, Assistant Director of APHIS Plant Protection and Quarantine, warned state officials about new pressure to phase out use of methyl bromide (MB) as a phytosanitary tool. Use of ozone-depleting chemicals – including MB – has been regulated since 1988 under the Montreal Protocol. Americans use more MB for this purpose than any other country. Already manufacturers are ending its production. After mentioning substitutes under development, the speaker urged state departments of Agriculture to meet with growers and develop a nation-wide plan to weather this impending change. She noted that APHIS has no authority to require companies to produce substitutes.

The NPB leadership discussed turnover in the organization (several states are represented by officials new to their jobs); advocacy to APHIS for even better coordination and recognition of states’ need to act quickly; and efforts to expand its collaboration with other entities. A series of presentations tallied lessons learned during specific plant pest crises. These included the role of the public in pest detection; mobilizing initial responses to a new pest; and building higher-ups’ and legislators’ support for funding a “rapid response” capability before arrival of a new damaging pest.

In a separate blog I reviewed topics discussed that pertain particularly to Pacific island plant health issues.

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

https://fadingforests.org

Status of Hawaiian species threatened by bioinvasion

stand of *Miconia* under albizia overstory on Big Island, Hawai`i; photo by F.T. Campbell

As I will describe in another blog, participants in the annual meeting of the National Plant Board link in Honolulu learned the basics about the uniqueness of agriculture and native species on remote Pacific islands. I want to complement this information by reminding you about other Hawaiian and Guamaian species at risk – although did not learn anything new.

As Martin and Andreozzi pointed out, the Pacific islands import nearly all their food and other consumables. Considerable interest in some quarters in Hawai`i to increase agricultural production. However, large swaths of land in the low-elevation area surrounding Pahoa on the Big Island is completely dominated by the albizia (Falcataria Molucca) [see photo above]. J.B. Friday says it is cost-prohibitive to remove these trees in order to restore agriculture in the area. Local people are concerned because in storms the trees fall onto houses and roads, causing considerable damage.

I saw numerous clumps of the notorious invasive plant Miconia calvescens. Dr. Friday told me that conservationists now focus on keeping this plant out of key areas, not trying to eradicate it completely.

area being restored by volunteers; photo by F.T. Campbell

Local people trying to restore disease-damaged forests by planting other native plants and hand-clearing invasive plants. Some of the ohia seedlings infected by Austropuccinia psidii.

ohia seedling with symptoms of ohia rust (*Austropuccinia psdii*); detected by J.B. Friday; photo by F.T. Campbell

Dr. Friday showed me many areas where ʻōhiʻa trees have been killed by rapid ʻōhiʻa death. Since this mortality occurred a decade or more ago, other plants have grown up. Pic In many if not most cases, this jungle includes dense growths of guava Latin the most widespread invasive tree on the islands (Potter). ‘Ōhi‘a trees continue to thrive in Hawai`i Volcanoes National Park – also on the Big Island – because the NPS makes considerable efforts to protect them from wounding by feral pigs. Demonstrates importance of fencing and mammal eradication in efforts to protect this tree species.

healthy ʻōhiʻa tree on cinder cone created by eruption of Kilauea Iki in 1959; photo by F.T. Campbell

I also saw healthy koa (Acacia koa) in the park, especially at sites along the road to the trail climbing Mauna Loa.

Regarding the wiliwili tree, I was told that it remains extremely scarce on Oahu.

wiliwili tree in flower; photo by Forrest Starr

I heard nothing about the status of naio – another shrub native to the Big Island – but on the dry western side of the island.

I rejoice that scientists are making progress in protecting and restoring Hawaii’s endemic bird species. Specifically, they are at the early stages of controlling mosquitoes that transmit fatal diseases. All 17 species of endemic honeycreepers that have persisted through the 250 years since Europeans first landed on the Islands are now listed as endangered or threatened under the federal Endangered Spp Act. The “Birds, not Mosquitoes” project has developed lab-reared male mosquitoes that, when they mate with wild female, the resulting eggs are sterile. (Male mosquitoes don’t bite, so increasing their number does not affect either animals or people.) Over time, the invasive mosquito population will be reduced, giving vulnerable native bird populations the chance to recover. Scientists began releasing these modified mosquitoes in remote forests on Maui and Kaua‘i in November 2023. In spring 2025, they began testing releases using drones. Use of drones instead of helicopters reduces the danger associated with flying close to complicated mountain rides in regions with variable weather. This project should be able to continue; the Senate Appropriations Committee report for FY26 allocates $5,250,000 for this project.

American Bird Conservancy is sponsoring a webinar about this program. It will be Wednesday, August 27, 2025 4:00 PM – 5:00 PM ET. Sign up for the webinar here

thicket of guava on the Big Island, Hawai`i; photo by F.T. Campbell

Finally, scientists are releasing a biocontrol agent targetting strawberry guava, Psidium cattleyanum, the most widespread invasive tree on the Islands (Potter et al. 2023). Distribution involves an interesting process. A stand of guava is cut down to stimulate rapid growth. The leaf-galling insect Tectococcus ovatus reproduces prolifically on the new foliage. Twigs bearing the eggs of these insects are collected and tied into small bundles. The bundles are then dropped from helicopters into the canopies of dense guava stands, where they establish and feed – damaging the unwanted host.

Guam

Guam’s endemic birds have famously been extinguished by the non-native brown tree snake. Dr. Aaron Collins, State Director, Guam and Western Pacific, USDA APHIS Wildlife Services, informed participants at the National Plant Board meeting about the extensive efforts to suppress snake populations in military housing on the island, reduce damage to the electric grid, and prevent snakes from hitchhiking to other environments, especially Hawai`i and the U.S. mainland.

The program began more than 30 years ago, in 1993. The program now employs 80 FTEs and has a budget of $4 million per year. It was initiated because live and dead snakes had been found in shipments and planes that landed in Hawai`i and the U.S. mainland. Avoiding the snake’s establishment on Hawai`i is estimated to save $500 million per year. The program is a coordinated effort by USDA, U.S. Fish and Wildlife Service, and the Department of Defense. Probably this estimate helped advocates reverse a decision by the “Department of Government Efficiency” to defund the program.

The program enjoys some advantages over vertebrate eradication programs on the mainland. For example, since Guam has no native snakes, it can use poison, e.g., in mouse-baited traps that can be dropped from planes. A recent innovation is auto-resetting traps baited with mammals; they can electrocute numerous snakes per night.

SOURCE

Potter, K.M., C. Giardina, R.F. Hughes, S. Cordell, O. Kuegler, A. Koch, E. Yuen. 2023. How invaded are Hawaiian forests? Non‑native understory tree dominance signals potential canopy replacement. Lands. Ecol. https://doi.org/10.1007/s10980-023-01662-6

Posted by Faith Campbell

https://fadingforests.org

FY26 Funding: APHIS doing well; will Congress save the USFS?

effects of emerald ash borer — one of the non-native pests threatening forests across the North American continent; photo by Leslie A. Brice, taken in Maryland

Forest Service: What the Administration Proposed

According to the Washington Post, the Administration’s plans for shrinking the federal government would cut employees of the U.S. Department of Agriculture (USDA) by 35% by 2026 – a loss of ~32,000 employees. Of these, the USDA Forest Service (USFS) was targetted for significant losses. The Administration proposed to end the Research and Development program, firing 1,641 employees. The State, Private, and Tribal program would lose 94% of its staff of 580 people. The National Forest System was to be cut by 30%, or 1,603 people. These and cuts to additional USFS programs would have totaled 39% of the agency’s approximately 30,000 staff.

The Administration issued a plan to reorganize USDA. This plan called for phasing out the USFS’ nine Regional Offices. Apparently only two offices would remain: a reduced state office in Juneau and an eastern service center in Athens, Georgia. Seven of the current stand-alone Research Stations would be consolidated into a single location in Fort Collins. The proposal retains two separate entities: the Fire Sciences and Forest Products Laboratories.

How Congress’ Appropriations Committees Responded

As I reported earlier, the Congress has not accepted these proposed cuts to the USFS. Under normal circumstances provisions in Congressionally-enacted appropriations legislation should prevail over the Administration’s plan, but now, who knows?

beech leaf disease — one of many non-native diseases threatening our forests that need further research; photo by F.T. Campbell

USFS Research and Development Program

The House Appropriations bill provides $301,706,000 for the research account, including $34 million for Forest Inventory and Analysis (FIA). The Senate bill provides more for the overall research program — $308.5 million; but a little less — $32 million – for FIA. I remind you that FIA data inform us about changes in the forest, including damage caused by introduced insects and pathogens. But these data do not identify or disseminate information about how such threats might best be countered.

The Senate bill specifically retains the USFS’ five regional offices and experimental forests. The report accompanying the bill specifies funding for several issues, especially needle blights on loblolly pine and western conifers and poor regeneration of white oak (Quercus alba). The only other topic of research mentioned in the bill is fire research. I fear that might led to decreased attention to non-fire aspects of introduced tree-killing insects and pathogens – which collectively threaten a similarly sized area of America’s forests.

USFS State, Private, and Tribal Forestry program

The House bill provides $281 million for the forest health program. The bill specifies that this funding “includes forest health management, invasive plants, and conducting international programs and trade activities.” This would seem to restore funding for the Forest Health Management program – both the “cooperative lands” and “federal lands” subprograms. However, I found no language specifying funding levels for each subprogram.

The Senate bill provides $38 million more — $319.5 million — for the forest health program. The report specifies that the Cooperative lands forest health management program should be funded at $42 million. However, the Appropriations Committee allocated significant proportions of this total to specific projects. Nearly a quarter of the appropriation targets the spruce budworm outbreak in the eastern U.S. Also, $2 million is earmarked for management of the sudden oak death pathogen in the forests of Oregon and California. Another $3 million funds a pilot program for management of the highly invasive plant cogongrass. Other priorities are programs targetting Western bark beetles and invasive woody plant species – although no funding levels are specified.

dead whitebark pine at Crater Lake National Park; photo by F.T. Campbell

The Senate bill also provides $19.6 million to support Congressionally-directed components of Forest Resource Information and Analysis; I don’t understand whether this is within or separate from the FIA program.

Under the National Forest System, the Senate bill instructs the USFS to spend at least $2 million per year on recovery of species of plants and animals listed under the Endangered Species Act, presumably including whitebark pines.

Animal and Plant Health Inspection Service

The USDA Animal and Plant Health Inspection Service (APHIS) is relatively well-off under the Administration’s plans. This agency is expected to lose 15% of employees – 1,180 people. According to Acting Deputy Administrator for Plant Protection and Quarantine Matthew Rhoads, 400 APHIS employees have accepted the Administration’s deferred resignation offer. Leaving are many program leaders – including the previous Deputy Administrator, Mark Davidson. While APHIS is allowed to hire to refill some positions, the future remains uncertain. I note a positive here: the new Farm Security Plan emphasizes efforts to combat bioterrorism, including APHIS’ safeguarding role. While I welcome that priority, I fear that the focus might be quite narrow, leaving out threats to natural resources such as native forest trees.

The impact of the proposed USDA reorganization on APHIS is unclear. The plan envisions continued reductions of the workforce and moving more than half of the remaining USDA employees away from Washington, D.C. to five regional offices.

APHIS also has done well under the House and Senate appropriations process. The House Appropriations Committee issued a press release touting its work as “Champions of U.S. farmers, agriculture, and rural communities”. The first example of this supportive effort reads: “Continuing critical investments in agricultural research, rural broadband, and animal and plant health programs.” Funding for APHIS is described as supporting the Trump Administration and its mandate from the American people. The Office of Management and Budget is said to have prioritized protecting American agriculture from foreign pests and diseases.

The Senate’s report instead cites traditional justifications for funding APHIS. It said that the appropriated funds will help protect the nation’s animal and plant resources from diseases and pests. (As usual, the examples cited are all animal diseases: chronic wasting disease, new world screwworm, and avian influenza.)

The reports accompanying both bills say agricultural quarantine – preventing pest introduction – is an important responsibility of the federal government. I am cheered by this statement since the Trump Administration puts such emphasis on shedding responsibilities.

Unlike the USFS, funding levels for most APHIS programs are unchanged from this year. (Of course, inflation has reduced the amount of work that can be carried out using the same amount of money.) The following table shows funding for programs of interest during the current year (FY2025) and levels proposed by the House and Senate bills for Fiscal Year 2026 (which begins on October 1).

Figures in millions of dollars (rounded up)

FY2025 enacted FY26 House FY26 Senate

APHIS total $1,148 $1,146 $1,168

Plant health subtotal $387.5 $388.6

Agric. quarantine $35.5 $35.5 $35.5

Field crop and rangeland $12 $11 $11.5

Pest detection $29 $28.5 $29

Methods development $21.5 $21.5 $21.5

Specialty crops $206.5 $216.3 $208.5

Tree and wood pests $59 $59 $58.6

Emergency preparedness and response* $44.5 $44.5 $44.3

* this fund is apparently for both animal and plant emergencies

The Senate and House bills contain identical language authorizing the Secretary “in emergencies which threaten any segment of [US] agricultural production …, [to] transfer from other appropriations or funds available to the agencies or corporations of [USDA] such sums as may be deemed necessary, to be available only in such emergencies for the arrest and eradication of contagious or infectious diseases … in accordance with sections … 431 and 442 of the Plant Protection Act … and any unexpended balances of funds transferred for such emergency purposes in the preceding fiscal year shall be merged with such transferred amounts”. The House report reminds the Administration that this language means that the emergency fund is intended to enhance, not replace, use of funds transferred from the Commodity Credit Corporation when confronting pest or disease outbreak emergencies. I have long sought increased funding for APHIS to respond quickly when a new invasive organisms is detected. Such flexibility is necessary because the regular process for adopting an appropriation stretches over about three years.

Also, both bills support continuation of APHIS’ feral swine management program. However, they prioritize funding projects in areas with the highest pig populations. I think this is backwards from the perspective of efficiency – although it might build political support for the program.

The House report mentions management of Arundo canes, said to be depleting groundwater levels in western states; eastern spruce budworm in the Northeast; spread of the southern pine beetle and spotted lanternfly; and invasions by the non-native shrub glossy buckthorn (Frangula alnus).

The Senate report notes that two strains of the sudden oak death pathogen Phytophthora ramorum and here – the EU1 and NA1 strains – pose major threats to Douglas-fir-tanoak forests in Oregon and California and the associated quarantines restrict exports of logs. Therefore, the report says funding for addressing this threat should be no lower than the FY24 level. (Oregon senator Jeff Merkley is the top Democrat on the Agriculture Appropriations subcommittee.)

I am thrilled to see that the House report requires APHIS to report within a year on recommendations to enhance existing protocols to better protect Hawai`i from bioinvasion. The report is to evaluate the feasibility of APHIS working with the state to improve biosecurity, prevent invasive species establishment, and mitigate damage from those already there. The report is to evaluate the risk of invasive species arriving via movement of people, baggage, cargo, and other items.

Finally, the “Big Beautiful Bill” adopted by the Congress in June, increased funding for APHIS’ Plant Pest and Disease Management and Disaster Prevention (Plant Protection Act Section 7721) from $75 million to $90 million – but only for Fiscal Year 2026. This grant program continues to be crucial to funding vital programs. This year the program has funded more than 300 projects. I wonder – might forest pathologists prepare a proposal for next year that would fund a study to improve America’s phytosanitary program regarding pathogens? Two possible study topics might be 1) evaluating the efficacy of APHIS’ current regulations in preventing introduction of fungal pathogens, oomycetes, bacteria, viruses, and nematodes on imported plants and/or 2) identifying currently unknown microbes resident in regions that are important sources of origin for traded plants, vulnerability of hosts in the U.S., and new technologies for detecting pathogens

Posted by Faith Campbell

https://fadingforests.org

USFS appropriations – Senate actions

The Senate Appropriations Committee has adopted its bill appropriating funding for the USDA Forest Service for Fiscal Year 2026, which begins on 1 October. Once the bill passes the full Senate, negotiators for the Senate and House committees must agree on a compromise.

The Senate bill provides a total of $8.6 billion for the Forest Service. This includes $308,497,000 for the Research and Development program. This is an increase of $8.5 million above funding for the current year. The Senate bill specifically supports retaining the five regional offices and experimental forests. Remember, the Trump Administration had proposed to eliminate the Research program – other than Forest Inventory and Analysis. The Committee’s report link specifies that the USFS should prioritize projects requested by or benefitting the agency’s mission, not requests by external entities. The benefit to the agency and public should be stated before a project is initiated. The report specifies funding for several issues, including

$3 million to continue collaborative research to determine distribution & movement of the pathogens that cause needle blight on loblolly pine.
Funding to maintain Experimental Forests in the Northeast. These are described as important for assessing the long-term response of eastern white pine & northern hardwoods to various forest management prescriptions, controlled burning & natural factors, such as insects, disease, weather events and climate change. While the wording is somewhat confusing, I believe this is funded at $6 million.
$1 million to support Outbreak Timber Salvage Research related to drought & needle tip blight & Ips beetle outbreaks in the West.
$3 million to support Needle Blight Mitigation collaborative research.
Several program areas related to fire, including understanding the risk in the wildland-urban interface.

Finally, the bill would fund Forest Inventory and Analysis at $32 million.

a white oak in Maryland; photo by Bob Gutowski via Flickr

There is particular attention to white oaks (Quercus alba). The report notes that this species occupies 103 million acres in E U.S. The species is critical for wildlife, biodiversity, & forest products. The Committee instructs the USFS to report on its efforts, including monitoring & research, to regenerate white oak on National forests as well as state, tribal, and private lands. The Committee recognizes importance of seed stock & tree nurseries in these efforts.

The bill also restores funding for the State, Private, and Tribal Forestry program. It provides $319.5 million for this, an increase of $16 million above the current level. Again, the Trump Administration had proposed to eliminate funding for the SPT program. The Senate report specifies that the Cooperative lands forest health management program should be funded at $42 million. However, the Committee also allocated significant proportions of this total to specific projects:

$10 million (nearly a quarter of the total) to support mitigation efforts targeting the spruce budworm outbreak in the eastern US.
$3 million for a Cogongrass Management Pilot Program
$2 million for management of the sudden oak death pathogen in the forests of Oregon and California
Prioritizing – but without specifying funding levels – of the Western Bark Beetle Initiative and helping urban areas restore and improve their forests and combat exotic invasive woody plant species.

There is also $19.6 million to support Congressionally-directed components of Forest Resource Information and Analysis – which is apparently separate from the FIA program.

The Senate bill also continues support for the USFS International Programs.

Under the National Forest System, the Committee instructs the USFS to spend at least $2 million per year on recovery of species of plants and animals listed under the Endangered Species Act. This category includes whitebark pines but not other tree species decimated by non-native pests.

whitebark pine with Clarke’s nutcracker; photo by Walter Siegmund

While I am disappointed that the Senate report makes few reference to non-native pests other than the loblolly needle blight, I rejoice that the Committee explicitly endorses the importance of USFS programs to sustain forest health across all landscapes – not just in National forests – and the Research program’s status as the premier such entity around the world.

Reminder: the House Appropriations bill provides $301,706,000 for the research account – almost $7 million less than the Senate. The House’ allocation for the Forest Inventory and Analysis (FIA) program is $34 million. Thus, there is a $9 million difference in funding levels – a significant challenge to reconcile. How will funding for the already-underfunded invasive species programs fare?

The House bill provides $280,960,000 for the State, Private, and Tribal forestry program. This is $38 million less than the Senate bill. The available report did not specify funding levels for the Forest Health Management program – either the “cooperative lands” or “federal lands” subprograms. As I note above, the Senate bill increases funding for the cooperative lands account, but then earmarks all the increase.

Posted by Faith Campbell

https://fadingforests.org

American Forest Congress calls for “urgent” action to counter forest pests

Eastern deciduous forest – Great Smoky Mountains National Park; photo by F.T. Campbell

Organizers of the American Forest Congress claim the meeting has influenced the direction of forest conservation and management in America since 1882. As examples they cite creation of the U.S. Forest Service, the establishment of the eastern National Forests, new community-based and collaborative approaches to forestry, and efforts to advance the leadership of women within the forest community.

During its meeting in Washington, D.C. in July 2025, the Ninth Forest Congress adopted a resolution re: threat from forest pests and pathogens:

Resolved: to recognize and address the urgent risk posed by exotic and native pests and pathogens and invasive species to long-term health, productivity and sustainability of America’s forests.

Provide adequate and sustained resources for a cooperative stewardship program to monitor and address these risks across landscapes and ownerships.

Convene regional partnerships with participation of state, federal and tribal authorities, private landowners, NGOs, universities and other interested stakeholders to identify key forest health risks, develop regional approaches and attract needed resources to implement and sustain them.

Brian Milakovsky, senior forester at the New England Forestry Foundation helped gather an ad hoc group of forest health experts and foresters from across the eastern seaboard to draft the resolution

The Committee now plans to organize a follow-up event sometime in 2025 to discuss what is needed to build a more diverse and robust funding pipeline for pest and pathogen work. Their concern was elevated by the Trump Administration’s proposal to stop funding for the USFS’ State, Private and Tribal Forestry program.

healthy hemlock forest, Cook Forest State Park, Pennsylvania; photo by F.T. Campbell

The New England Forestry Foundation has a direct stake in these programs. The Foundation manages 41,000 acres of land in five New England states and works with diverse landowners in the region to improve forest management. The Foundation hopes to expand both on-the-ground work and advocacy in response to the threats from non-native insects and pathogens. While they are focusing on developing an IPM program on their own lands, they recognize that they must address the pest and pathogen levels of the surrounding landscape – that is, they wish to support the federal and state forest health experts who are trying to address these issues at the largest scale.

In Maine the Foundations is trying to manage destruction by the hemlock woolly adelgid (HWA), beech bark disease, beech leaf disease, winter moth, red pine scale, and browntail moth. The emerald ash borer is arriving – and threatens to decimate green ash forests covering entire hillsides – with repercussions for water supplies, flooding, etc.

This resolution presents a great opportunity to revive discussions about the non-native forest pest issue with federal and state government officials, fellow conservationists, and the foundations that fund conservation work. Let’s work individually and together to put real muscle into these programs.

One of the possible ways is to persuade Congress to adopt the bill under development by Sen. Peter Welch of Vermont. The bill as introduced in the previous session is available here. Please ask your senators to sponsor it in this session – perhaps as a component of the (overdue) 2024 Farm Bill.

Posted by Faith Campbell

https://fadingforests.org

Funding for key USFS programs – reprieve in House

The House Appropriations Committee, Subcommittee on Interior, adopted its version of appropriations for the USDA Forest Service (USFS) for Fiscal Year 2026, which begins October 1^st. The bill restores the basic funding levels for the Research and Development and State, Private, and Tribal Forestry accounts. (The Trump Administration had called for cutting nearly all funding for these accounts.)

The Subcommittee provides $301,706,000 for the research account. I am having difficulty determining the funding level for the current year (FY25) since the Administration and Congress have taken several contradictory actions. I am disappointed that $34 million of the research total is allocated to the Forest Inventory and Analysis (FIA) program. FIA data inform us about changes in the forest, including damage caused by introduced insects and pathogens. But FIA data do not identify or disseminate information about how such threats might best be countered. I had asked Congress to begin increasing the proportion of research funds allocated to studying the invasive forest pests.

Furthermore, the only other topic of research mentioned in the bill is fire research. I fear that might led to decreased attention to non-fire aspects of introduced tree-killing insects and pathogens – the opposite of what I think is appropriate.

one of numerous risk maps for *Phytophthora ramorum*; many aspects of this pathogen still require research – perhaps especially the likelihood that the three strains present in forests in Oregon & California will reproduce sexually

The Subcommittee provides $280,960,000 for the State, Private, and Tribal forestry program. This is apparently a $23 million cut for the overall SPT program. The bill specifies that this funding “includes forest health management, invasive plants, and conducting international programs and trade activities.” This would seem to restore funding for the Forest Health Management program – both the “cooperative lands” and “federal lands” subprograms. I doubt that the funding will reach the level I suggested: $32 million for the cooperative lands subprogram and $16 million for the federal lands subprogram.

Still, it is a great relief that the Congress has – so far – chosen to maintain these programs, which are so critical to countering invasions by non-native organisms. I hope the full House and the Senate will agree. Please contact your senators and remind them how important these programs are.

(Some other important programs have been sacrificed in the appropriations bill – A 23% cut in the budget for the Environmental Protection Agency; reversing some regulations intended to protect various endangered species …)

Posted by Faith Campbell

https://fadingforests.org

Wood packaging pest risk — will we pay for the crazy import rush in early 2025?

The Washington Post has summarized data on the number of container ships travelling from China to U.S. west coast ports for the first half of 2025. It compares those numbers to the same period in 2024.

For the first four months, the trips exceeded 2024 levels, often by considerable amounts, as importers sought to get their goods before President Trump imposed high tariffs. Thus, the number of container ships arriving at Los Angeles, Long Beach, Oakland, Seattle, and Tacoma during each month:

January: 17% increase
February: 32% increase
March: 14% increase
April: 5% increase

In May, landings from China decreased by 33%! Those ships arriving also carried fewer containers.

When measured by the value of imported goods, imports from China fell 20% nationwide when we compare April 2024 to April 2025. This decrease was seen at four of the five west coast ports; the exception was Tacoma.

When President Trump “paused” the 145% increase in tariffs on Chinese goods, the prices shippers charge for transporting containers doubled – from less than $3,000 per container to $6,000. This change probably portends a rebound in import volumes.

I always worry about containers from China (see Haack et al. 2022; full citation at the end of this blog; and this blog). For more than 30 years they have too often been the means by which wood-boring insects are introduced to North American forests. I fret even more when import volumes are rising – especially when importers are in a rush. I suspect that neither exporters nor importers pay much attention to whether the crates and pallets have been treated properly.

ash tree killed by EAB — the risk of woodborers introduced in wood packaging; photo courtesy of John Hieftje, former mayor of Ann Arbor, Michigan

I have asked the Bureau of Customs and Border Protection for comment, but have not yet received a reply.

Please note that these data do not include information about imports from other Asian countries … or shipments destined for U.S. ports in the Gulf or Atlantic (via the expanded Panama Canal) or to Canadian ports.

SOURCE

Haack RA, Hardin JA, Caton BP and Petrice TR (2022) Wood borer detection rates on wood packaging materials entering the United States during different phases of ISPM#15 implementation and regulatory changes. Frontiers in Forests and Global Change 5:1069117. doi: 10.3389/ffgc.2022.1069117

Posted by Faith Campbell

https://fadingforests.org

Tree deaths in a National Park – what I saw

In June I visited Shenandoah National Park (SHNP) (above) for the first time in years. The Park’s forests are mostly mature secondary forests, having recovered over the 90 years since establishment from earlier logging and clearing for small-scale farms and pasture.

While I loved the forest and the vistas, I was aware of which species are missing …

Five years ago I blogged about a study by Anderson-Teixeira et al. (full citation at the end of this blog) that reported on the changes in the forests of SHNP and the neighboring Smithsonian Conservation Biology Institute (SCBI). This is important because, as Fei et al. (2019) (full citation at the end of this blog) documented, nine of the 15 most damaging introduced forest pests grow in eastern forests. In fact, the greatest increase in biomass loss has occurred in Eastern forests. Seven are found specifically in SHNP (Potter et al. 2019; full citation at the end of the blog).

Anderson-Teixeira et al. report that non-native forest pests caused a loss of about a quarter of ecosystem above-ground biomass between 1991 and 2013 across 66 sites. These invasions occurred after the worst impacts of chestnut blight, which entered the country ~120 years ago – before “modern” phytosanitary programs were instituted. Still, total above-ground biomass has largely recovered through germination and growth by trees in other genera. Greatest increases have been by tulip poplar (Liriodendron); oaks (Quercus); ash (Fraxinus) – but see below; birch (Betula); and maples (Acer). And while several taxa were lost from monitoring plots in SHNP and SCBI, a-diversity also remained steady.

So what does that look like on the ground?

American chestnut used to dominate many Eastern forests, composing more than one-third of the pollen assemblage in some stands (Fei et al.) According to Anderson-Teixeira et al., chestnut trees larger than 10 cm DBH disappeared by 1910, killed by chestnut blight. In past decades I frequently saw chestnut root sprouts when hiking. The National Park Service now urges visitors to hike to low elevation sections of the South River Trail to see such sprouts.

In the 1980’s, groves of eastern hemlocks occupied about 9,800 acres in SHNP, primarily in shaded valleys and along streams. Invasion by the hemlock woolly adelgid killed 95% of these hemlocks. Anderson-Teixeira et al. document the species’ disappearance from their study plots by 2007. Park staff treated more than 20,000 hemlocks using injections of imidacloprid. In 2015, the Park began partnering with Virginia Polytechnic Institute and State University in releasing predatory biocontrol beetles (Laricobius spp.) While the beetles have shown promising establishment and spread, it is now recognized that additional biocontrol agents will be needed to suppress the adelgid. The Park plans to allow releases of predatory silver flies (Leucotaraxis spp.) in remaining hemlock sites and will begin to phase out the imidacloprid treatments.

I remember the hemlocks! But this year, at least in the creek valleys where I hiked, I saw almost no remnants – not even fallen logs.

fallen hemlock; all photos by F.T. Campbell in Shenandoah NP in June 2025

And I remember the flowering dogwoods. They are almost gone now from the Appalachian chain, killed by dogwood anthracnose. Their status in SHNP is unclear. Anderson-Teixeira et al. report flowering dogwoods only from the Smithsonian property. There, they declined by almost 90% from the study plots from 2008 to 2019. The Park’s list of tree and shrub species reports that flowering dogwood is still “abundant”; my visit was too late in the season to observe how visible flowering dogwoods still are. Certainly the species survives the disease better in open settings, e.g., meadows and roadsides. I don’t know how the three other native Cornus species were affected.

Dead ash are still visible. Ash trees made up about 5% of the Park’s forest cover. Anderson-Teixeira et al. report that ash aboveground biomass was increasing in SHNP and stable on the SBCI property before arrival of the emerald ash borer (EAB). EAB-caused mortality was first detected in 2016. In just three years — by 2019 – 28% of green, white, and black ash had died; this meant a loss of 30% of ashes’ aboveground biomass. Ninety-five percent of remaining live trees were described as “unhealthy’’. In an effort to retain ash trees for visitor enjoyment, reduce threats to visitors from hazard trees, and to preserve a portion of the park’s ash tree communities until host-specific biological controls become available, SHNP staff – supported by specially trained volunteers and interns, Virginia Department of Forestry and Fairfax County – began treating high-value ash with emamectin benzoate. They began at Loft Mountain Campground, a location (elevation 3,300 feet) where ash trees make up most of the forest. Three hundred forty three trees were treated there — exceeding expectations for what could be accomplished in a single year. The park hopes to treat an additional 200-400 trees. They will target ash trees around campgrounds, picnic areas, overlooks and other areas frequently used by visitors. These efforts were supported by the Shenandoah National Park Trust and here.

I saw many dead oaks – probably the result primarily of repeated attacks by the spongy moth link beginning in 1982. Oak-dominated study plots in SHNP lost on average 25% of individuals and 15% of above-ground biomass. After 1995, when spraying of Bacillus thuringiensis var. curstaki improved control efforts (at the expense of native moths), oak aboveground biomass increased gradually, driven by individual tree growth rather than recruitment. Oak abundance continues to decline due to oak decline and absence of management actions to promote regeneration (Anderson-Teixeira et al.). These authors do not mention oak wilt although a decade-old map shows the disease to be present just to the west of the Blue Ridge (visible here).

Fortunately Shenandoah National Park has relatively few American beech, so it will be less affected by beech leaf disease (BLD). The Blue Ridge is also far from large waterbodies — which promote the disease. However, I did see some beech sprouting in creek valleys – probably in gaps opened when the hemlocks died. These valleys with higher humidity are the type of ecosystem most conducive to the disease! Anderson-Teixeira et al. note that they did not analyze the impact of beech bark disease – which was the disease of concern before arrival of BLD and continues to be present.

They also did not evaluate the impacts of balsam woolly adelgid, described as having decimated high-elevation populations of firs (Abies balsamea); white pine blister rust on eastern white pine; or EAB on fringetree (Chionanthus virginicus) in SCBI. Nor did they document the impact of thousand cankers disease (TCD) on walnuts or butternuts. This concerns me because they report that the disease “appears to be affecting Juglans spp. in our plots.” Furthermore, butternut (J. cinera) had been ‘‘common’’ in 1939, but had disappeared from SHNP by 1987. On the Smithsonian property, the four individuals found originally had declined by half – to two living individuals. Butternut has suffered high levels of mortality throughout its range from butternut canker.

The understory tree redbud (Cercis canadensis) also declined precipitously – by almost76% from 1995 to 2018 in SCBI plots. While Anderson-Teixeira et al. do not speculate why, a few years ago a wider decline was reported.

Of course, Shenandoah also has been invaded by non-native plants! So I saw some plants that should not be there. At least the mid- and high-elevations that I visited appear to be much less abundant in the Park than in coastal and piedmont regions of Virgina. Ailanthus is listed as “common” in the Park. I didn’t see Japanese stiltgrass but it is clearly present at lower elevations. I was particularly disturbed to see oriental bittersweet along trails located in all three sections of the Park.

The Blue Ridge PRISM is targeting 12 species: autumn olive, garlic mustard, Japanese honeysuckle, Japanese stiltgrass, kudzu, mile-a-minute, multiflora rose, oriental bittersweet, porcelainberry, privet, tree of heaven, and wavyleaf grass.

SOURCES

Anderson-Teixeira, K.J., V. Herrmann, W.B. Cass, A.B. Williams, S.J. Paull, E.B. Gonzalez-Akre, R. Helcoski, A.J. Tepley, N.A. Bourg, C.T. Cosma, A.E. Ferson, C. Kittle, V. Meakem, I.R. McGregor, M. N. Prestipino, M.K. Scott, A.R. Terrell, A. Alonso, F. Dallmeier, & W.J. McShea. 2021. Long-Term Impacts of Invasive Insects & Pathogens on Composition, Biomass, & Diversity of Forests in Virginia’s Blue Ridge Mountains. Ecosystems

Fei, S., R.S. Morin, C.M. Oswalt, & A.M. Liebhold. 2019. Biomass losses resulting from insect & disease invasions in United States forests. Proceedings of the National academy of Sciences.

Potter, K.M., M.E. Escanferla, R.M. Jetton, G. Man, & B.S. Crane. 2019. Prioritizing the conservation needs of United States tree spp: Evaluating vulnerability to forest insect & disease threats. Global Ecology & Conservation.

Posted by Faith Campbell

https://fadingforests.org

Call for new approach to biological conservation – integrating bioinvasion

whitebark pine in Glacier National Park killed by white pine blister rust

The Kunming-Montreal Global Biodiversity Framework (KMGBF) is a major global policy driver around the world for more effective action to preserve biodiversity from current and future threats. (However, the United States has not joined the underlying treaty, the Convention on Biological Diversity (CBD). So its importance is probably less in the United States than in countries that take part.) This relatively new Framework was adopted at the 15^th Conference of the Parties (COP) of the CBD in December 2022 after four years of negotiations. However, cynics note that the 196 countries that are parties to the CBD have rarely met previous ambitious goals set at earlier COP.

Hulme et al. have just published a paper [full reference at the end of this blog] addressing how invasive species and this Framework’s target may interact. They note that conserving biodiversity costs money. Many of the countries hosting diverse and relatively intact ecosystems lack sufficient resources, capability, or robust governance structures for this conservation.

The Kunming-Montreal Global Biodiversity Framework sets out ambitious global targets to reduce biodiversity loss by 2030 so as to maintain the integrity of ecosystems and their constituent species. Of the 23 targets, one – Target 6 – addresses bioinvasion. Countries endorsing the CBD have committed to eliminating, minimizing, reducing and/or mitigating invasive species’ impacts on biodiversity and ecosystem services. This is to be accomplished by identifying and managing introduction pathways; preventing introduction and establishment of priority invasive species; reducing rates of introduction and establishment of known or potential invasive species by at least 50% by 2030; and eradicating or controlling invasive species, especially in priority sites.

I rejoice that the CBD parties have recognized invasive species as a major driver of biodiversity loss in terrestrial and marine ecosystems. I wish conservation organizations’ and funders’ activities clearly reflect this finding.

This is the challenge raised by Hulme et al.: countries must integrate efforts to counter bioinvasions into overall conservation programs. Success in curbing bioinvasion depends upon achieving almost all other KMGBF targets. And this is a two-way street: the more holistic approach offers greater likelihood of successful biodiversity conservation.

The same authors point out that some of the 22 other targets address rapidly evolving introductory pathways e.g.,

Target 15 – increasing international and domestic tourism;
Target 12 – encroachment of urban areas near protected areas;
Target 10 – development of intensive agriculture or aquaculture systems near protected areas;
Target 7 – species rafting on plastic marine pollutants; and
Target 8 – growing risk from species shifting ranges in response to climate change.

pallet graveyard behind camp store & snack bar art Lake MacDonald, Glacier National Park; photo by F.T. Campbell

Other targets relate to management of established invasive species, e.g.,

Target 1 – planning and priority-setting for allocation of limited resources among the various threats to biodiversity;
Identifying factors that pose risks to highly-valued species, e.g., threatened species (Target 4) and species that provide important ecosystem services (Target 11);
Target 19—obtaining necessary financial resources.

A final group of targets are intended to guide all conservation efforts. These goals include integrating biodiversity concerns in decision-making at every level (Target 14); reducing harmful economic incentives and promoting positive incentives (Target 18); and several targets addressing issues of equity, benefit sharing, and access to information. Hulme et al. assert that the threat posed by bioinvasions must be incorporated into policies, regulations, planning and development processes and environmental impact assessments across all levels of government.

Hulme et al. decry an imbalance as to which KMGBF targets have been the focus of attention from governments, conservation organizations, and media. These stakeholders have concentrated on

Target 3, which calls for extending legal protection to 30% of lands and waters by 2030;
Target 4, which promotes maintaining genetic diversity within and among populations of all species;
Target 7, which encourages reducing harmful pollution;
Target 15, which urges businesses to decrease biodiversity risks arising from their operations; and
Target 21, which advocates ensuring equitable and effective biodiversity decision-making.

Even when stakeholders have looked at Target 6, they have focused primarily on how to quantify the numbers of species being introduced to novel ecosystems. Hulme et al. argue that conservationists should instead concentrate on the challenge of achieving the target. They note that bioinvasion is worsening despite implementation of many long-term management programs. As they note, numbers of introduced species globally have increased, these species are occupying larger geographic areas, and the species’ measured impacts have risen to astounding levels (see my previous blog about new cost estimates). This same point was made two years ago by Fenn-Moltu et al. (2023) [full citation at the end of this blog]; they found that the number of invasive species-related legislation and treaties to which a country adheres did not relate to either the number of insect species detected at that country’s border or the number of insect species that had established in that country’s ecosystems.

As conservationists, Hulme et al. remind us that not all damages are monetary: invasive species threaten more than half of all UNESCO World Heritage Sites.

Hulme et al. say achieving Target 6 presents several scientific challenges – most of which have been discussed by numerous other authors. Introduction pathways are changing rapidly. There is great uncertainty regarding current and especially future propagule pressures associated with various pathways. Information about particular species’ impacts and where they are most likely to be introduced is insufficient. Management costs are routinely underestimated. Perhaps most challenging is the need to judge programs’ effectiveness based not simply on outputs (e.g., number of acres cleared of weeds) but on outcomes in relation to reducing the subsequent impact on biodiversity and ecosystem services.

I note that several environmental organizations endorsed a “platform” that discussed this last point a decade ago. [I have rescued the NECIS document from a non-secure website; if you wish to obtain a copy, contact me directly through the “comment” option or my email.] Unfortunately, the coalition that prepared this document no longer exists. Even when conservation organizations have invasive species efforts, they are no longer attempting to coordinate their work.

I greatly regret that Hulme et al. continue a long-standing misrepresentation of international border biosecurity controls as consisting primarily of inspections — of imported commodities, travellers, and associated transport conveyances. I have argued for decades that inspections are not effective in preventing introductions. See Fading Forests II Chapter 3 (published in 2003); Fading Forests III Chapter 5 (published in 2014); “briefs” describing pathways of introduction prepared for the Continental Dialogue on Non-Native Forest Insects and Diseases – in 2014 and in 2018.

The weaknesses of visual inspection are especially glaring when trying to prevent introductions via wood packaging material and living plants — also here.

Hulme et al. propose a politically astute approach to finding the resources to strengthen countries’ efforts to curtail invasive species’ spread within their borders. Recognizing that no country has unlimited resources to allocate to managing invasive species, they suggest concentrating slow-the-spread efforts on preventing damage to legally protected areas. Furthermore, authorities should avoid designating as new “protected areas” places that are already heavily invaded – or at risk of soon becoming so. As they note, programs aimed at protecting these areas often engage conservation stakeholders, decision-makers, even potential non-governmental donors. In other words, there is a foundation on which to build.

To buttress their argument, Hulme et al. cite evidence that bioinvasions threaten these areas’ integrity. For example, Cadotte et al. (2024) found that bioinvasion is one of most frequently identified threats identified in a survey of 230 World Heritage sites; and that they pose a greater degree of concern than other threats to biodiversity. They reiterate that managing invasive species is one of the most effective interventions aimed at protecting biodiversity.

The task remains complex. Hulme et al. note that accurate information about pressure caused by invasive species is not easily quantified using remote sensing. It requires expensive on-the-ground data collection. Even current methods for ranking invasive species have crucial gaps regarding species’ potential impact and the feasibility of their control. Choosing management strategies also requires assessing potential unintended effects on biodiversity and other GBF Targets, e.g., pollution from pesticides (Target 7).

Still, the context remains: successful management of bioinvasions to support the integrity of protected areas depends on the integrative approach described above.

Hulme et al. note a contradiction within the Kunming-Montreal Global Biodiversity Framework: Target 10 calls for the agriculture, aquaculture, and forestry industries to adopt sustainable practices, but doesn’t raise the issue of these sectors’ role in the introduction and spread of invasive species. They say guidelines have been developed for sustainable forestry production. These guidelines recommend that commercial plantation forests not plant non-native tree species within 10 km of a protected area. Hulme et al. also suggest applying a “polluter pays” fine or bond to forestry businesses that use invasive species without sufficient safeguards to prevent escape. These funds could be accessed to support invasive species management in protected areas, particularly surveillance. (Target 19 mandates obtaining more funds for this purpose). They add that these aquaculture, agriculture, horticulture and forestry sectors should take action to prevent the local feralization of alien crops and livestock.

Target 8 calls for minimizing the impacts of climate change on biodiversity. Hulme et al. note numerous scientific challenges here, including understanding how specific ecosystems’ and native species’ are vulnerable to altered climates, along with how specific invasive species’ are responding to an altered climate regime.

These same authors provide specific recommendations to the global conservation community to put in place a more holistic perspective. Some recommendations deal with data integration. Others call for major undertakings: i.e., developing a protected area management toolkit at a global scale. This action will require significant investment in capacity-building of protected area managers plus international cooperation and technology transfer (Target 20). Hulme et al. suggest funding this effort should be a priority for any resources leveraged from international finance (Target 19).

Hulme et al. also propose changes in the conservation approaches advocated by the CBD and IUCN. Specifically, they call for more explicit consideration of current and future impacts of bioinvasions and their management — on protected areas. The needed activities fall into six areas:

(1) reduce risks associated with various pathways;

(2) plan for range-shifting invasive species;

(3) mitigate invasive species’ impacts on biodiversity and (4) on ecosystem services;

(5) ensure new protected areas (including urban green spaces and infrastructure corridors) are largely free of established (“legacy”) invasive species; and

(6) provide managers sufficient resources to take effective action.

SOURCES

Fenn-Moltu, G., S. Ollier, O.K. Bates, A.M. Liebhold, H.F. Nahrung, D.S. Pureswaran, T. Yamanaka, C. Bertelsmeier. 2023. Global flows of insect transport & establishment: The role of biogeography, trade & regulations. Diversity & Distributions DOI: 10.1111/ddi.13772

Hulme, P.E., Lieurance, D., Richardson, D.M., Robinson, T.B. 2025 Multiple targets of Global Biodiversity Framework must be addressed to manage invasive species in protected areas. NeoBiota 99: 149–170. https://doi.org/10.3897/neobiota.99.152680

Posted by Faith Campbell

https://fadingforests.org

Invasive shot hole borers – global travellers

*Erythrina caffra* (native tree in South Africa) infested by PSHB; photo by J. Paap

A complex of closely related ambrosia beetles continues to be introduced to new places and cause increasing damage. The most widespread is the polyphagous shot hole borer (PSHB) Euwallacea fornicatus ss. Other members of the complex include the Kuroshio shot hole borer (KSHB) E. kuroshio and a third species, E. interjectus. Each beetle harbors its own plant-pathogenic fungus – all in the Fusarium genus.

Places invaded and impacts

The PSHB is established in the U.S. (southern and central California), Israel, South Africa, & Australia. The outbreak in South Africa covers the largest geographic area; the PSHB-Fusarium disease has been found in eight of the country’s nine provinces (every province except Limpopo) (Bierman et al. 2022). The South Africa outbreak is the most extensive geographically of all of them (Mudede et al. 2025).

The KSHB is established in southern California, from where it has spread to neighboring Mexico. E. interjectus is established in Santa Cruz County in California.

A fourth member of the species complex, E. perbrevis, has been established for decades on several Hawaiian islands and for at least 20 years in Florida. E. perbrevis has also been detected in nurseries in the Netherlands, but authorities reported it has been eradicated. E. perbrevis has long been known to be present in northern Queensland; this region might be part of its native range.

South America

In 2023 PSHB had been detected in Argentina – reported as E. fornicatus. A few weeks ago it was reported in neighboring Uruguay (PestLens for June 26, 2025). The beetle in South America is a different haplotype (genetic strain) than that introduced in South Africa, Israel, and California. It is more similar to specimens found in European greenhouses (Ceriani-Nakamurakare & others) As of 2022, scientists had identified 43 haplotypes (genetic variants) of E. fornicatus s.s. identified around the world; the greatest diversity is in several Asian countries (P. Rugman-Jones, pers. comm). The other species also comprise several haplotypes.

In South America the beetle has been observed attacking several new hosts. The most frequently attacked hosts are are Acer japonicum (Japanese maple) and a Ficus sp. Other hosts that support the full life cycle of the beetle and its associated fungus are Bauhinia forficata (cow’s foot), Ceiba speciosa (floss silk tree), Diospyros inconstans (jacuiba), Ficus aspera (mosaic fig), Fraxinus excelsior (European ash), Gardenia thunbergia (white gardenia), Geoffroea decorticans (chañar), Myrsine laetevirens, and Neltuma (Prosopis) caldenia (caldén) plants (PestLens June 26, 2025).

South Africa

The beetle and disease have been present since 2012 or earlier although it was not detected until 2017 (Winzer et al.). (This delay in detection is typical; in California PSHB was present for probably nine years before it was detected.) Winzer et al. decry the communication failure that resulted in the delayed official detection in South Africa and propose a system to correct the breakdown.

The haplotype (genetic strain) is the same as that found in Vietnam and introduced in California and other sites (Mudede et al.).

The South Africa outbreak is the most extensive geographically of all the outbreaks globally; within five years of its official detection, the PSHB-Fusarium disease was confirmed to be present in eight of the country’s nine provinces (every province except Limpopo) (Bierman et al. 2022).

More than 100 tree species – native and exotic – have been confirmed as hosts. Sources differ on the specific number: Mudede et al. report 130 species; Townsend et al. 2025 report 162. Both figures include both hosts that support reproduction of the insect and those that do not.

Mudebe et al. cite other studies that project the Fusarium disease will cause a decline in tree populations over a 10-year period of between 3.5% and 15.5%. They estimate the cost of removing urban trees killed by the disease will be $USD18.45 billion.

The impact in South Africa might differ from other invaded areas. Mudebe et al. report that over the five years of the study none of the Platanus species or A. buergerianum was dying despite being heavily infested. They say this suggests that trees can survive for more than 5 years.

Townsend et al. present a more disturbing picture. Their study examined PSHB impacts in plots in native forests in two provinces — KNZ (where PSHB first detected) and Western Cape. Over five years, PSHB invaded seven forest types; the only forest type not invaded was mangroves. PSHB colonization was detected on 43 native tree species. Eighteen species were recorded as competent hosts (able to support PSHB reproduction), eight as kill-competent hosts (can be killed by PSHB).

Over the five years 11 individual trees belonging to seven species died as a result of PSHB infestations. Some died very rapidly (within 2–5 years of first infestation); some died after apparently minor levels of infestation.

Each year of the study trees had a 7.5% increased chance of PSHB infestations; the number of entrance holes rose by over 10%. This means – no surprise – that the longer PSHB is active in the enviro the more trees it will infest, the higher its impact will be on hosts, & the higher the # of dispersing individuals produced. This will substantially increase the chances & rates of additional areas becoming infested, especially in areas close to infestation borders. Townsend et al. state that PSHB populations might be increasing exponentially – as occurred in California and Israel.

Townsend et al. discuss factors that might explain differing levels of infestation. Currently, a higher proportion of trees in the study plots in KwaZulu-Natal were infested than in the plots in Western Cape. The most likely explanation is that PSHB established there first – before 2012 compared to possibly five years later in the Western Cape. Other factors might be that source populations in the Western Cape were often found in alien tree species in urban areas distant from the study plots, while in KwaZulu-Natal, the beetles were frequently found in indigenous trees within monitoring plots. Forests in KZN are also fragmented, unlike the nearly contiguous woodlands in the Western Cape, and closer to urban areas with high PSHB infestation levels.

Although the PSHB’s spread into natural forests seems to be slow, Townsend et al. warn that they expect an increase in the rate of infestations as progressively more competent host individuals are infested. They fear severe ecological effects from rapid mortality of some key tree species, especially those sensitive to comparatively few attacks. They mention the native Erythrina caffra (coral tree), which is an important component of coastal forest ecosystems, especially in KwaZulu-Natal.

Other native trees at particular risk of PSHB infestations are Diospyros glabra, Ficus, Sparmannia africana, Trichelia emetic, and Vepris lanceolata. Townsend et al. remind us that each native tree species has a specific role in normal ecosystem functioning and supports a unique suite of species. Even if attacked trees do not die, Fusarium infection might weaken them, thereby increasing their susceptibility to other pathogens and pests, decreasing their longevity, or reducing their ability to produce fruits and flowers which can have long-term direct & indirect effects on normal ecosystem functioning & resilience.

Remember, South Africa is a biodiversity hotspot, home to its own Floral Kingdom!

The South Africans are trying to find more efficient methods for tracking spread of PSHB. Mudede et al. 2025 tested whether Google street view (GSV) images can be used to monitor its spread in urban forests. The test took place in Johannesburg. The test demonstrated that GSV images can be useful for mapping and monitoring PSHB-FD infestation on Platanus trees – but not on trees with rougher bark, e.g., Acer. While there were no false positives for any host species, most of the maple trees were misclassified as non-infested (false negatives).

Vietnam

Even in its native range, PSHB is a threat – in this case, to plantations utilizing non-native or exotic tree species. Thu et al. describe a growing number of pests threatening reforestation efforts in Vietnam. Surveys over the period 2011 to 2020 revealed outbreaks by 14 new insect species and 2 pathogens. Only two of the trouble-causing species are themselves non-native to Vietnam. One of these is PSHB. Thu et al. report the species’ range has spread rapidly in the country.

Thu et al. inform us that Vietnam has a high diversity of forest trees – and that almost nothing is known about pests that attack these trees.

*Neolamarkia cadamba* – native tree in Vietnam that might be resistant to PSHB; via Flickr

I welcome their call for higher investment in selection and breeding of hosts resistant to the various pests. The limited effort so far has identified provences of Neolamarckia cadamba and Nauclea orientalis that display some resistance to PSHB. Thu et al. advocate breeding programs to address the main biotic threats. They also recommend several actions to improve biosecurity, including enhanced hygiene in tree nurseries; improved silvicultural practices to minimize damage to trees; diversification of tree species being grown; and strengthening biosecurity and quarantine programs. They note that early detection of pest outbreaks is critical, so the country should develop forest health monitoring protocols for extensive forest reserves – sentinel plantings and remote sensing to detect trees under stress.

On a personal level, I found it interesting that Mudede et al. report that Google street view imagery determined that the invasive tree Ailanthus altissima dominates the street tree population in Istanbul – despite not having been intentionally planted. I visited Istanbul in April – and saw evidence of invasive vines and possibly the North American tree Cercis canadensis.

SOURCES

Ceriani-Nakamurakare, E., A.J. Johnson, D.F. Gomez. 2023. Uncharted Territories: First report of Euwallacea fornicates (Eichhoff) in South America with new reproductive host records. Zootaxa, 5325 (2), 289-297. https://doi.org/10.11646/zootaxa.5325.10

Mudede, M.F., S.W. Newete, K. Abutaleb, M.J. Byrn. 2025 Monitoring a polyphagous shot hole borer infestation in an urban forest using Google street view in the City of Johannasburg, South Africa Biol Invasions (2025) 27:144 https://doi.org/10.1007/s10530-025-03595-4

Thu, P.Q., D.N. Quang, N.M. Chi, T.X. Hung, L.V. Binh, B. Dell. 2021. New and Emerging Insect Pest and Disease Threats to Forest Plantations in Vietnam. Forests 2021, 12, 1301. https://doi.org/10.3390/f12101301

Townsend, G., M. Hill, B.P. Hurley, and F. Roets. 2025 Escalating threat: increasing impact of the polyphagous shot hole borer beetle, Euwallacea fornicatus, in nearly all major South African forest types. Biol Invasions (2025) 27:88 https://doi.org/10.1007/s10530-025-03551-2

Winzer, L.F, K.T. Faulkner, T. Paap, and J.R.U. Wilson. Preprint. From detection to action—a proposed workflow to ensure first reports of alien spp from molecular analyses are acted upon DOI: https://doi.org/10.3897/arphapreprints.e162421

Pest-lens link: https://pestlens.info/

Posted by Faith Campbell

https://fadingforests.org