Eradicate ALB – of course! But what about the other pests?

The Asian longhorned beetle (ALB) is the target of most of APHIS’ spending on non-native, tree-killing insects and pathogens. I have been on the record for 18 years – representing a sequence of three organizations – supporting ALB eradication efforts. But other damaging pests do not get adequate attention. Much of the explanation is probably money – APHIS is inadequately funded. But why have the other tree-killers slipped from the attention of politically important constituencies? How do we reverse this situation so that needed actions are taken?

The ALB Eradication Effort

After consulting several sources — Haack 2009, periodic news releases by APHIS and the Ohio Department of Agriculture – I conclude that in the 20 years since ALB was detected in Brooklyn in 1996, US and Canadian authorities have removed at least 188,000 trees. Data on the numbers of high-risk trees treated with systemic pesticides are much less complete. However, it appears from these same sources that U.S. and state authorities have treated more than 800,000 trees. Easily available data do not reveal how many of the treated trees were later found to be infested and therefore had to be cut down. I do hope agency and academic scientists are tracking that information – it is crucial to evaluating the efficacy of programs that allow treatment of “high risk” trees instead of removing them. A related issue is how many trees at early stages of infestation are missed by surveyors.

In carrying out the eradication program over 20 years, APHIS has spent about $600 million (Santos pers. comm.;  US Department of the Interior 2016). Canada has spent far less – something more than $35 million Canadian (Marcotte pers. comm.).

In FY15 APHIS allocated $41.6 million to eradication of the Asian longhorned beetle [US DoI 2016]. This represented 77% of all funds in the agency’s “Tree and Wood Pests” account. The President’s FY17 budget calls for cutting funding for this account from its current level of $54 million to $46 million. If Congress accepts President’s proposed cut and funding for ALB eradication remains at the FY15 level, the proportion allocated to this one pest would rise to 90% of the total account. Perhaps APHIS anticipates spending less on the ALB program. APHIS has announced (USDA news release) that it will  no longer apply systemic pesticides to “high-risk” trees in order to prevent beetle infestation. Instead, the program will focus on identifying and removing infested trees. I worry that with ALB outbreaks still present in Massachusetts, New York, and Ohio, any reduction in the program would be risky. (Official USDA budget documents don’t provide an explicit funding level for the ALB program, so we can’t be sure whether cuts are planned.)

Certainly, ALB eradication deserves continued priority. The beetle kills trees in 15 botanical families – especially maples and birches, which constitute much of the hardwood forest reaching from Maine to Minnesota, as well as urban trees worth an estimated $600 billion. Furthermore, adequately funded eradication efforts have proven to be a successful tactic.

pshb_1PSHB damage to coast live oak;

photo by Akif Eskalen, UCRiverside

Other tree-killing insects are being ignored

However, other species need to be addressed, too. If these efforts are to succeed, they need more than the leftovers from funding ALB work.

Some funds are available through the Farm Bill Section 10007 “Plant Pest and Disease Management and Disaster Prevention Program” grant program. Still …

The Asian gypsy moth demands constant attention from APHIS. That effort is ramping up in response to moth detections in the Pacific Northwest. Apparently most of the funds for this program are from the Farm Bill Section 10007 program – but how long can this funding source be sustained? (See my blog posted earlier in March.)

Efforts to eradicate the spotted lanternfly (Lycorma delicatula) from Pennsylvania continue. The lanternfly attacks 25 or more plant species that grow in the Mid-Atlantic states.  Concern focuses on grapes and fruit trees including apples and stone fruits. (The lanternfly prefers tree of heaven (Ailanthus) (PA DoA) but the insect’s host range is too wide to use it as a biocontrol agent for this widespread invasive plant. The spotted lanternfly entered country as egg masses attached to imported slate. It has been detected in four counties in southeastern Pennsylvania ]

What is – or should be – done about the 20 species of non-native wood-boring and bark insects that have been detected for the first time in the United States over just the past decade? While some appear not to be causing major damage, that impression could be wrong. The polyphagous shot hole borer was first detected in California in 2003 ]. It has taken over 10 years to determine that the PSHB and very similar Kuroshio shot hole borer transport fungi that threaten over 300 plant species, including trees that make up the majority of trees in riparian areas and half of the trees planted in urban areas across southern California.

Tree species in other warm regions of the country such as the Gulf Coast are also at risk if the shot hole borers’ spread is not curtailed. Examples include native boxelder and American sweetgum; as well as such widely planted ornamentals as camellia, mimosa, and Japanese maple. The insects and the Fusarium pathogen that they transport might also attack other species in the oak, maple, sycamore, holly, and willow genera which grow in the Southeast.

Other funding needs

APHIS needs to continue efforts to slow the spread of and reduce impacts on forests from the emerald ash borer, including by continuing to support programs aimed at curtailing movement of firewood. While the emerald ash borer has spread to 25 states, significant areas of natural and urban ash forests remain pest-free, especially in the deep South, Great Plains, and Pacific Coast. APHIS might also continue funding research aimed at improving both biological control and breeding of ash trees resistant to the emerald ash borer.  See my blog about resistance breeding posted in February.

APHIS must also have sufficient resources to respond when additional insect introduction are detected – which seems likely since an estimated 35 shipping containers entering the country each day carry wood packaging infested by damaging pests. [see my blogs about wood packaging posted in July and August 2015 and the SWPM fact sheets.

And – as the AGM and spotted lanternfly examples demonstrate – the risk of introduction of tree-killing insects goes far beyond imports of “agricultural” commodities – even when those commodities are widely interpreted to include wooden crates and pallets.

Please re-visit my blogs of 22 February to learn the details of funding issues and then contact your Representative and Senators to support increased funding for APHIS.


Posted by Faith Campbell



Haack, R.A., F. Herard, J. Sun, J.J. Turgeon. 2009. Managing Invasive Populations of Asian Longhorned Beetle and Citrus Longhorned Beetle: A Worldwide Perspective. Annu. Rev. Entomol. 2010. 55:521-46.

Marcotte, M. Canadian Food Inspection Agency. Email to F.T. Campbell 29 April, 2013.

Pennsylvania Department of Agriculture: Agriculture Secretary Urges Consumers to Help Keep Foreign Insect from Spreading through Pennsylvania, United States ​News for Immediate Release Nov. 3, 2014

Santos, R. USDA Animal and Plant Health Inspection Service. Email to F.T. Campbell, April 12, 2013.


Contact: Rhonda Santos, (508) 852-8044,

Suzanne Bond, (301) 851-4070,

U.S. Department of the Interior. 2016. Safeguarding America’s lands and waters from invasive species: A national framework for early detection and rapid response, Washington D.C., 55p.


Asian gypsy moth – the risk is still too high

The Asian gypsy moth would be more damaging than the European gypsy moth because it feeds on a wider range of plants – including conifers – and the female flies – speeding up its spread.

lymdi18Asian gypsy moth; John H. Ghent;

The United States and Canada have a joint program – under the auspices of the North American Plant Protection Organization (see RSPM #33 here) aimed at preventing introduction of species of gypsy moths native to Asia. The principal risk arises from moths attaching their egg masses to ships (and containers on deck) when the ships visit ports in Far Eastern Russia, China, Korea, and Japan.  The NAPPO standard originally went into force in March 2012.  Under its terms, ships leaving ports in those countries during gypsy moth flight season must be inspected and cleaned before starting their voyage.


Gypsy moth populations rise and fall periodically; thus, it is much more likely that egg masses will be attached to ships during years of high moth population densities.


These variations are seen in U.S. and Canadian detection reports.

AGM Interceptions by year

United States                            Canada

2010                 4

2011                21

2012                44                                32

2013                42                                33

2014                76                                39

2015                  7                                15


(U.S. data from Kevin Harriger, Bureau of Customs and Border Protection, at the 2015 meeting of the Continental Dialogue on Non-Native Forest Insects and Diseases [] ; Canadian data from Wendy Asbil, National Manager, Invasive Alien Species and Domestic Plant Health Programs Section, Plant Health and Biosecurity Directorate, Canadian Food Inspection Agency


While most AGM detections are at West Coast ports, the risk is not limited to that region. In 2013, Asian gypsy moths were detected at Baltimore, MD; Charleston, SC; Savanna and Brunswick, GA; Jacksonville, FL; New Orleans, LA; Houston and Corpus Christi, TX; and McAlester, OK.

Well aware of the risk associated with ships, U.S. and Canadian customs officials are vigilant in conducting inspections; if egg masses are found, the ships are required to return to international waters and clean off the egg masses.  The ships are inspected again before they are allowed back into port.  The process delays deliveries that are often on tight schedules and costs hundreds of thousands of dollars.

However, the risk is not limited to the ships themselves.  In 2014, more than 500 Asian gypsy moth egg masses were found on four shipments of imported steel slabs arriving at ports on the Columbia River. Efforts were made to clean the more than 5,000 steel slabs, but some egg masses were still present after the cleaning.  The steel was then sent to a furnace for final processing; the furnace heated the steel to  more than 2,000oF – sufficient to kill any remaining eggs! Still … (report by APHIS: Asian Gypsy Moth interceptions and mitigation of risk at Columbia River Ports of Entry, 2014. 18 February 2015)


Some question whether a global company with annual earnings close to $2 billion can be persuaded to take the necessary steps to ensure that its imports are free of gypsy moth eggs.  The cleanup costs charged  by APHIS would be minimal.


Besides, cleaning large steel plates is apparently difficult and probably requires fumigation with methyl bromide – which must be administered in a closed facility with appropriate safety measures.

Implementing the NAPPO standard that presents a unified front to Asian exporters – they must clean ships headed to North America – clearly has reduced the risk of introduction of Asian gypsy moths.  But the smaller risk remains.  Indeed, Oregon and Washington occasionally catch small numbers of Asian gypsy moths in their traps.  In 2015, ten Asian gypsy moths were trapped in Washington State (Report of the Technical Working Group for the Response to Asian Gypsy Moth Captures Washington-Oregon  2015 October 30, 2015).

Oregon caught two Asian gypsy moths in the Portland area (15,000 traps had been placed statewide; the state also trapped 12 European gypsy moths). Previous detections of Asian gypsy moth in Oregon were one each in 1991, 2000, and 2006. Two of these moths were trapped near the location of the 2015 detections.  A vessel that called at Tacoma in January 2013 had 275 egg masses.

The Asian gypsy moths were caught in traps across a broad area, including eight captures around  southern Puget Sound and three in the Portland, OR/Vancouver, WA area.  For these and other reasons, experts concluded that it is likely that females moths are also present in one or more of these areas (Report of the Technical Working Group for the Response to Asian Gypsy Moth Captures Washington-Oregon  2015 October 30, 2015).

The expert group recommended enhanced trapping plus eradication at the four sites where captures were clustered. The group discussed the pros and cons of various approaches, including spraying with Btk, Diflubenzuron (“Dimilin”), or Tebufenozide (“Mimic”); or with Gypchek (gypsy moth nuclear polyhedrosis virus); and  augmentation of spray programs by releasing sterile males.

Both Washington and Oregon plan gypsy moth eradication measures in 2016.  Washington plans to treat 10,500 acres at seven locations in Pierce and Thurston counties (both at the southern end of Puget Sound).   Oregon will spray in several places in northern and northwest Portland.


Posted by Faith Campbell



Invasive Plants: a major threat to forests of the East

Go anywhere in the woods of the East, you are likely to see Japanese or shrub honeysuckles, multiflora rose, privets, Japanese stiltgrass, garlic mustard, Chinese tallowtree, … .

BW2308104 (Bargeron)

Japanese honeysuckle; Chuck Bargeron;


A new study confirms how widespread these invasive plants are.

Christopher Oswalt and colleagues (2016) have studied the data from the national Forest Inventory and Analysis (FIA) program of the United States Forest Service. They found that almost 40% of forests in the United States are invaded by alien plant species. Furthermore, forests in the eastern United States have been invaded by more invasive plant species than those in the West.

Large numbers of invasive plants are established in the United States. As I noted in this blog in January, nearly 10,000 non-native plant species are present, although not all are invasive. (See Rod Randall’s report here ).
The USDA Forest Service develops region-specific lists in consultation with invasive plant experts. Then the authors normalized the data by calculating the proportion of forested subplots in each county with at least one invasive species present. Oswalt and colleagues then used this percentage to define invasion intensity for those plots that contain any invasive plants on the region or state-specific monitoring lists. They mapped the subcontinental spatial distribution of invasive plants based on this measure of “invasion intensity”.
Nationwide, 39% of forested plots sampled contained at least one invasive species. There are significant regional differences. To no-one’s surprise, Hawai`i had the highest invasion intensity – 70%. Second highest density is in the eastern forests – 46%. Forests in the West ranked third, with 11% of plots containing at least one of the monitored invasive plant species. Finally, forests in Alaska and the Intermountain regions both had 6% of plots invaded. This finding might surprise some because of the level of political attention given to plant invaders on grazing lands in the West.
The authors attributed clusters of more highly invaded counties to disturbance, e.g., fragmentation in the North Central region and major travel corridors in the Piedmont of the Southeast.
I would rephrase the principal cause as “propagule pressure”. While forests of the East are certainly small and surrounded by other land uses – that is, fragmented – these are also areas where invasive plants have been extensively planted – some for nearly a century. Some – e.g., honeysuckles, multiflora rose, and lespedeza – were intentionally planted in woodlots as food or cover for wildlife.
Another factor is the great diversity of invasive plant species present in the East and thus available to spread into the forest by such mechanisms as transport of seed by birds and other wildlife. The Southeast Exotic Pest Plant Council maintains a list of approximately 400 invasive species.  The Mid-Atlantic Invasive Plant Council has a list of 285 invasive plants. Many of the invaders in both lists are herbs, shrubs, or trees which can invade shaded environments.
The top five most frequently detected invasive plants in the Southeast were Japanese honeysuckle, privets, roses, lespedeza, and microstigium. The first four have been deliberately planted either directly in “natural” areas or in yards and gardens throughout the region. The top five species for the Northeast and Midwest are multiflora rose, reed canary grass, garlic mustard, Japanese honeysuckle, and common buckthorn. Again, four of these have been widely planted deliberately. Note that few of these species’ seeds are spread by wind.

In contrast, the top five species in the Intermountain West are less frequently planted intentionally: cheat grass, Canada thistle, spotted knapweed, houndstongue, and musk thistle. Invasive plants in forests of the Pacific states fall between these poles, as they include planted species, such as Armenian blackberry, and unplanted ones, such as cheat grass and medusahead.

Clearly the threat from invasive plants is great and growing (see my blogs from January for discussions of other aspects of the problem). What should we do to counter it?
• Those who sell plants for any use – ornamental horticulture, ground cover, livestock forage, soil amelioration, wildlife habitat management, biofuels – should commit to avoiding species that are known or suspected to be invasive in the region.
• Voluntary efforts to limit sales of invasive plants have fallen by the wayside. The various Invasive Plant Councils should work with industry groups and others to renew this effort. Also, the Councils should propose a joint list of additional plants for APHIS regulation under NAPPRA (see below).
• Those who buy plants for these various uses should make a similar commitment – especially large, institutional buyers like state highway departments.
• Concerned citizens should lobby their state governments and the Congress to fund ongoing “noxious weed” programs and to ensure that these programs include plant species that threaten natural areas, not just weeds of agriculture.
• Concerned citizens should lobby the Congress to increase funding for federal agencies’ invasive plant control programs, especially those addressing natural areas, and especially in Hawai’i and the eastern United States. Also, the U.S. Department of Agriculture needs to adopt procedures that enable APHIS to act more quickly to curtail introduction and human-assisted spread of invasive plants. Most urgently, APHIS should finalize the May 2013 proposal to restrict importation of 22 species under the NAPPRA program (see my blog “Invasive plants – huge numbers! Continuing spread …” from January and the description of the NAPPRA program here).
Christopher M. Oswalt, Songlin Fei, Qinfeng Guo, Basil V. Iannone III, Sonja N. Oswalt, Bryan C. Pijanowski, Kevin M. Potter 2916. A subcontinental view of forest plant invasions. NeoBiota. 24: 49-54

Posted by Faith Campbell

Feral Hogs: numbers climbing, threats to soils & ecosystems increasing, no control in sight

Introduced wild hogs (Sus scrofa) threaten ecosystems across the continent and on islands ranging from Hawai`i to the Caribbean.

large_hog_damage (MO)  feral hogs in Missouri

Pigs are the ultimate survivors – highly adaptable and prolific. Most of the damage is done by their rooting for plant parts and invertebrates in the soil, and by wallowing to cool themselves and fend of biting insects. Depending on soil type (density, moisture level, compaction), pigs may root to depths of three feet below the surface (USDA APHIS EIS).

Feral hogs consume primarily plant matter. They prefer hard mast – e.g., acorns, beechnuts, chestnuts, or hickory nuts. Pigs can be formidable competitors with native wildlife for this nutritious food. Feral hogs also eat algae, fungi, invertebrates such as insects, worms, crustaceans, and bird and reptile eggs. In addition, they feed on small animals, including reptiles, fish, amphibians, ground-nesting birds, and young of wild game and domestic livestock. They even feed on larger animals – although it is not clear whether they kill such animals or only scavenge their carcasses (USDA APHIS EIS).

Since pigs lack sweat glands, they wallow in water and mud to cool off. Some wallow sites are used for years. Adjacent areas are usually denuded of vegetation and the soils are compacted. Wallows are commonly located in or adjacent to riparian or bottomland habitats (USDA APHIS EIS).

Despite the apparent damage, only a few studies address the feral hogs’ impacts on soil structure, chemistry, bulk density and nutrient cycling. The conclusions of those studies are mixed (USDA APHIS EIS).

In Great Smoky Mountains National Park, feral pigs are reported to “plow up” areas in search of bulbs, tubers and wildflowers and to consume small mammals, snakes, mushrooms, bird eggs, and salamanders. (The Smokies are a center of endemism for salamanders.) Wallows are said to contribute significantly to stream sedimentation, thereby harming aquatic life.
Furthermore, feral hogs contribute to both human and animal disease. Their feces contaminate water and soil with coliform bacteria and Giardia which are both a threat to human health. Some of the wild pigs also carry Pseudorabies, a disease that is almost always fatal to mammals, including such important wildlife species as black bear, bobcat, elk, white tailed deer, red fox, grey fox, coyote, mink, and raccoon. Pseudorabies from wild boar can survive in humid air or water for up to seven hours and in plants, soil, and feces for up to 2 days.

Unfortunately, the United States’ population of introduced wild pigs has dramatically increased since 1990. People are to blame. map

States with feral hog populations; provided by John Mayer, US Department of Energy, Savannah River National Laboratory

According to John J. Mayer, the number of states with established wild boar populations has risen from 19 in the 1990s to 37. The total number of feral hogs has risen from an estimated 1 to 2 million animals to a range of 4.4 to 11.3 million (Mayer).

The overwhelming majority of the feral hogs is found in only 10 states –AL, AR, CA, FL, GA, LA, MS, OK, SC, TX. Texas has the largest numbers, 30 to 41% of the U.S. total, depending on whether one is counting the states’ animals by mean, maximum, or minimum estimates.

Why have people transported feral pigs to so many new places over the last 20 years? Largely because hunters wanted an exciting game animal to pursue (USDA APHIS EIS; Mayer). In Tennessee, populations of feral swine (probably released by farmers to forage for themselves) were relatively stable and confined to only a few counties from the 1950s through the 1980s. However, since a statewide, year-round, no bag-limits hunting program was instituted in 1999, pig populations have expanded rapidly. In 2011, nearly 70% of counties had pockets of feral swine (USDA APHIS EIS).

But hunting is not an effective means of controlling the animals’ populations and damage. Mayer reports that sport hunters remove about 23% of a wild pig population annually. Models demonstrate that 50 – 75% of a wild pig population must be removed annually, year after year, in order to reduce or eradicate that population (J.J. Mayer pers. comm]

Mayer says there are currently no effective management tools or options to reduce or control feral hog populations in most situations. I note that the Hawaii Volcanoes and Haleakala National parks have been able to eradicate feral pigs through determined efforts.

Missouri is one state that is tackling feral hogs aggressively. In January, the Missouri Conservation Commission approved changes to the Wildlife Code of Missouri  that would prohibit the hunting of feral hogs on lands owned, leased, or managed by the Missouri Department of Conservation. A public comment period on the proposed regulation change will run from April 2 through May 1. After considering the citizen input and staff recommendations, the Commission will reach a decision whether to finalize the new regulation – probably in September. (Missouri has quite extensive material on feral hogs posted here
Meanwhile, the Missouri Department of Conservation has reached out to several partners to strengthen its increase the number of feral hog traps it can place and enhance communication to the public. These partners include such agricultural organizations as the Missouri Farm Bureau and Missouri Pork Producers; and such conservation organizations as the National Wild Turkey Federation and two quail associations.

New York has gone farther; it has adopted a policy of eradicating Eurasian wild boar from the state. To achieve this goal, the state in October 2013prohibited importing, breeding, or releasing Eurasian boars. As of September 2015, it has been illegal to possess, sell, distribute, trade or transport Eurasian boars in New York. Hunting or trapping of Eurasian boars is illegal except for law enforcement officers, farmers, and landowners authorized by the Department of Environmental Conservation (DEC). The hunting ban was adopted in order to minimize breakup of sounders so as to facilitate eradication trapping by trained conservation officers. For more information, visit the DEC website.

Mayer, J.J. 2014. Estimation of the Number of Wild Pigs Found in the Unted States. August 2014 SRNL-STI-2014-00292, Revision 0.

U.S. Department of Agriculture Animal and Plant Health Inspection Service
Final Environmental Impact Statement. Feral Swine Damage Management: a National Approach May 27, 2015
Posted by Faith Campbell