Recent information raises several troubling/worrisome issues:
1. The overall collapse in trade and travel has severely cut into the collection of user fees. These fees pay for Agriculture Quarantine Inspectors, putting jobs at risk. Their inspections provide important incentives for importers to follow U.S. and international rules to limit pests.
2. The list of imports from China in 2020 includes $1 billion worth of nursery stock. This is down about 7% from 2019. However, from the perspective of preventing plant diseases and pests, these imports continue to be high risk and still not adequately addressed by U.S. policy.
3. Other Asian regions are gaining in import share. Thus we can expect to see more pests arriving from countries other than China, like Vietnam.
Loss of User Fees Could Mean Loss of Inspectors
The collapse of trade and travel has a more troubling result: severe reductions in user fees collected from travelers and importers to fund DHS/Customs and Border Protection Agriculture Quarantine Inspectors. In a recent opinion piece, several former administrators of APHIS warn that current user fee collections are insufficient to sustain inspectors’ employment. A reserve fund will also be depleted this month. APHIS estimates that it will require an appropriation of $630 million to fund these agricultural inspections through the next fiscal year (October 2020 – September 2021).
Agricultural inspectors focus on plant and animal imports – including horticultural stock, seeds, fruits, and vegetables – both in commercial shipments and in passengers’ baggage. They are also called in when CBP inspectors suspect pests are present in wood packaging.
I do not consider inspection to be the most effective strategy to prevent introductions. That is, I think inspections are less effective than regulations requiring treatments and pre-shipment pest-mitigation measures. However, losing inspectors – even temporarily – will undermine detection and enforcement as an incentive for importers to comply with U.S. and international rules. This funding crisis is therefore a serious concern. Please ask your senators and member of Congress to support increasing the appropriation for DHS CBP by $650 million to keep these inspectors on the job.
Imports from Asia Skyrocket
New data show that containerized US import volumes from Asia rocketed 91% between March and August. During the same five-month period a year ago, import volumes rose only 36% — so the 2020 increase is more than double the earlier pace. Numbers of incoming containers from Asia nearly doubled at the ports New York/New Jersey; Los Angeles/Long Beach, California; and Savannah, Georgia. The California ports are reported to be working nearly at capacity. This has resulted in higher handling costs and delays in trucking imports out of the port to their destinations.
Import volumes from Vietnam and India continue outpace the market generally.
Update: Imports from China Continue to Decline Relative to Other Source Regions
In August I posted a blog reporting a significant reduction in imports from China recently – first as a result of new tariffs in 2019, and second, as a result of the global economic crash associated with the Covid-19 virus.
Imports from China decreased by 16% in 2019 compared to 2018, then rose slightly in the first months of 2020. My focus then – and now – is on declining imports of heavy goods — the types of imports most likely to be packaged in wooden crates or on wooden pallets that can transport pests.
Import volumes from China rose later in the year, as the U.S. economy began to rebound. Official data from the U.S. Bureau of the Census shows US imports from China had more than doubled (by value) since March — from $19.8 billion in March to $40.7 billion in July. Still, imports of heavy items and most consumer items – other than computers – have decreased in 2020 compared to 2019.
Included in this list of imports is $1 billion worth of nursery stock – down about 7% from 2019. Nursery stock imports are rarely included in Census reports, so I value this information. Of course, these imports – even ‘though declining – still represent a series plant pest risks. One study showed that imported plants carry a pest risk 12 times higher than wood packaging material (Liebhold et al. 2012; see full reference at end of blog).
rhododendron infected by sudden oak death – photo courtesy of Jennifer Parke
Important Shifts in Sources of U.S. Imports
Data show a broad and years-long decline in the share of U.S. imports that come from China. This decline is best seen in declining volumes of imports arriving at the ports of Los Angeles, Long Beach, Northwest Sea Alliance and another port in the region. Imports arriving at these ports declined 5.3% in May 2019 compared to May 2018. At that time, this decline was blamed on importers having stocked up in advance of threatened US tariffs on goods from China. Bureau of the Census data show a 2% reduction in loaded twenty-foot-long containers (TEUs) entering Long Beach in calendar year to date 2019 compared to calendar year to date 2020 (through August).
Commercial data sources indicate even larger declines. According to the Journal of Commerce, the twin ports of Los Angeles and Long Beach handled 37.7% of the loaded TEUs entering the United States in 2018. This fell to 33.5% in July 2020 — a drop of 4.2 percentage points in just 18 months. The author of this article said the reason was a fall in imports from East Asia (including China, Hong Kong, Japan, South Korea, and Taiwan) compared to Southeast Asia, Europe, then South America and, finally, South Asia (primarily India). The article provides a table quantifying shifting sources of U.S. imports:
Total US Market Share Imports by Source Region
SOURCE 2018 2019 2020YTD 2018-2020 change
East Asia 61.6% 58% 54.5% -7.1%
Europe 14.9% 15.8% 16.9% +1.9%
Southeast Asia 8.3% 10.5% 11.9% +3.6%
South America 8.2% 10.5% 11.9% +3.6%
South Asia 2.7% 3.1% 3.1% +0.5%
Other source regions – e.g., the Caribbean, Middle East, Pacific, Africa, and Atlantic – were all below 2% of total numbers of TEU in all three years, and changed not at all or minimally over this period.
As I noted in the earlier blog, the pest risk persists. First, imports from China continue, and the most recent data (for the period 2011-2016) indicate significant numbers of shipments continue to be in violation of requirements for wood packaging (APHIS database / pers. comm). Remember, USDA passed up an opportunity to raise the issue of non-compliant wood packaging with Chinese phytosanitary officials.
Plus other regions also are the source of pests. I wrote about the risk from Mexico in the previous blog. The region of Southeast Asia has already been the source of highly damaging pests, e.g., redbay ambrosia beetle and polyphagous shot hole borer.
distribution of laurel wilt, carried by redbay ambrosia beetle
Scientists have also detected numerous known and previously unknown species of the brown alga genus Phytophthora in Vietnam and Taiwan. Of course, this is the genus that includes the pathogens that cause sudden oak death, black ink disease, potato blight, and numerous other plant diseases. APHIS has not accepted my urging to undertake rapid assessments of the vulnerability of North American trees to these newly discovered microbes.
SOURCE
Liebhold, A.M., E.G. Brockerhoff, L.J. Garrett, J.L. Parke, and K.O. Britton. 2012. Live Plant Imports: the Major Pathway for Forest Insect and Pathogen Invasions of the US. www.frontiersinecology.org
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
Reminder: Friday is the deadline for commenting on APHIS’ draft environmental assessment for the Asian longhorned beetle eradication program in South Carolina. Comments should be submitted at https://beta.regulations.gov/commenton/APHIS-2020-0086-0001
The Center for Invasive Species Prevention submitted comments that supported the eradication effort because of the well-documented threat that the ALB poses to the forests of North America. We also supported the preferred alternative in the EA.
However, we found the environmental assessment (EA) to be deficient in several ways:
the EA does not identify the host species present in the program area – not even of the 5,800 trees inspected by the program as of mid-August.
the EA provides no estimate of the proportion of deciduous trees and shrubs in the area that are host species. Conifers dominate the area. This means that any fauna dependent on deciduous trees and shrubs for food and shelter already contend with limited resources. Consequently, while we concur with the EA that any impacts will be localized, they might be exacerbated by the relative rarity of hardwood species in the local area. It is particularly important that the EA address this question since the Programmatic EIS was written under the assumption that forests at risk to the ALB are like those in the Northeast and Midwest, where hardwoods dominate.
Without knowing the proportion of deciduous flora comprised of host species, no one can evaluate the amount of wildlife food that could be removed or treated by pesticides. Some wildlife species are potentially vulnerable, including those that feed on pollen and nectar (i.e., bees and other pollinators) and those that feed on insects and other invertebrates. The latter include two species listed federally as threatened species: the frosted flatwood salamander (Ambystoma cingulatum) and northern long-eared bat (Myotis septentrionalis). Also vulnerable are birds, 96% of which feed their young on insects and other invertebrates. I worry about sublethal effects and possible bioaccumulation. Aquatic organisms, especially invertebrates, might also be affected.
The information gaps in the EA highlight weaknesses in the Programmatic EIS, on which it relies. The most important gap is the dearth of pesticide dose/mortality data for terrestrial amphibians. Apparently, EPA has not required such studies before approving pesticides.
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
APHIS has apparently passed up an opportunity to pressure China to clean up its wood packaging – although China ranks among the countries that most often violates ISPM#15 and sends wood packaging infested by quarantine pests. (See the blogs under the category “wood packaging” on this site.)
In May, a large delegation of APHIS employees met (virtually) with an equally large delegation of its Chinese counterpart to negotiate “technical protocols” linked to the Phase 1 trade agreement with China. The focus of the negotiations was on Chinese phytosanitary barriers that block exports of US products to China.
The two countries have now signed technical protocols to allow the United States to export to China a wide range of commodities estimated to be worth between $700 million and $760 million annually when the agreement is fully implemented. These commodities include barley for processing, hay, some fruits (blueberries, avocados, nectarines), almond meal, and chipping potatoes.
Some of the agreements cap years of effort. The example cited is chipping potatoes. Negotiations continue on some other U.S. exports to China, including logs.
An article in APHIS’ online newsletter reports that “On the import side, we are working on the requirements for China’s requested commodities….” Presumably these would be exports to the U.S. The examples listed were all fruits.
US & Chinese delegations (APHIS photo)
I inquired whether wood packaging was part of the negotiation.
Andrea B. Simao, Assistant Deputy Administrator and Director of PPQ’s Phytosanitary Issues Management unit, replied that SWPM was not raised “since there has [sic] not been significant issues.” Instead, she detailed efforts in the ongoing negotiations to persuade China that U.S. phytosanitary treatments are sufficient to control various pathogens in logs: oak wilt, phosphine on conifers, pinewood nematode.
Apparently the focus was fully on US exports and nobody raised US concerns about the risks of imports from China. This approach fits the Administration’s emphasis on exporting agricultural commodities to China. However, this is not reality. Over the past five years, I have frequently cited USDA’s own data – which demonstrate the likelihood that wood packaging will transport tree-killing pests from China to the U.S.
APHIS PPQ Deputy Administrator Osama El-Lissy & Chinese counterpart Li Jainwei sign agreement (APHIS photo)
Please inform your Member of Congress and Senators (or candidates for House or Senate) about how you feel about this failure of USDA to protect America’s natural resources. We must raise the political heat in order to pressure USDA into placing as high a priority on protecting US natural resources as it does on supporting agricultural exports.
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
Ash forest in Michigan killed by emerald ash borer photo by Nate Siegert
As I reported in December, the USDA Forest Service Forest Health Management program has been issuing reports on the status of pest invasions, based on annual national Insect and Disease Surveys (IDS). This survey is carried out by low-level aerial surveys of statistically valid geographic units. (For a discussion of quadrat establishment, see the Introduction to the 2019 report here.
Here I compare the pest situation as it appeared in two recent years, based on these surveys: 2017 and 2018.
Of course, two years is too short a time to see trends. The second report provides USFS scientists attempt to provide context by analyzing 20 years of data (Chapter 6 of the 2019 report).
These reports are important sources of data on the status of non-native pests in our forests, but I raise several caveats that necessitate our continuing to rely on additional sources, some of which I have cited in previous blogs. I will address these in greater detail below. But in brief, these caveats are:
1) Major pests – both in extent and damage caused – are not adequately included (see below).
2) The survey technique resulted in delays in detecting mortality. It cannot be used as an early detection tool.
3) There is little analysis of the statistics cited.
Why Stakeholders Cannot Rely on These Two Survey Reports Alone
I hope stakeholders, analysts, and decision-makers will utilize the full range of reports and other data to evaluate the presence and impacts of various invasive pests and pathogens. Even the reports’ authors advise decision-makers to use other forest health indicators in addition to this report. It is not the “fault” of the authors that these reports cannot serve all needs. However, we all need to be aware this caveat.
1. Important Pests Not Adequately Included.
Many of the most damaging non-native pests caused extensive damage before these surveys were initiated. These include white pine blister rust, chestnut blight, Dutch elm disease, butternut canker, Port-Orford cedar root disease, European gypsy moth, and balsam woolly adelgid on Fraser fir. [For further discussion, see pest write-ups here and my earlier blogs reviewing 30 years of engagement and survey data from Shenandoah National Park.]
2. Major Damaging Pests Are Poorly Captured by the Survey Method.Morin found that non-native pests had caused a five percent increase in mortality nation-wide – as measured by tree volume. Three of the species suffering the highest rates of this “exacerbated mortality” are redbay, ash, and hemlock. The current studies’ authors concede all three are poorly detected by the survey methods. The aerial survey techniques are ill-suited to detect mortality of tree species that grow scattered throughout a diverse forest. Other seriously damaging pests that are poorly detected by aerial surveys are Dutch elm disease, white pine blister rust, and thousand cankers disease. Again, see the species write-ups here to be reminded about how great the pest’s impact are. Also review my earlier blog reviewing 30 years of my engagement with the issue and survey data from Shenandoah National Park.
dead redbay in woods photo by F.T. Campbell
Given these caveats above, what do these studies show us?
Areas surveyed.
Since 1999, the annual Insect and Disease Survey (IDS) has covered on average 266,655,000 ha, although the area varied from a maximum of 320,712,000 ha (in 2007) to a minimum of 202,170,000 ha (in 2017), then increased to 211,34,000 ha in 2018. For reasons not clear to me, the proportion of forested area in the lower 48 states surveyed actually declined from 2017 to 2018 – from 55.1% to 46.6%. In Alaska, the 2017 surveys covered about 7.3% of the total forested area but 12.7% of the forested area in 2018. In Hawai`i, the survey covered about 80.1% of the forested area in 2017, but only 69.4% of the State’s total tree canopy area in 2018.
Tree-Killing Insects and Pathogens Found.
The 2017 survey identified 63 mortality-causing agents and complexes that cumulatively affected 3.27 million ha in the lower 48 states – about 1.3% of the total 252 million ha of forested land in these states. Of these agents of tree mortality, 23 were detected killing trees on areas totaling larger than 5,000 ha each.
The 2018 survey identified seven fewer mortality-causing agents – only 56. These agents were detected on about 2.13 million ha across the lower 48 (slightly less than the combined land area of New Jersey and Rhode Island), or about 0.8% of the total forested area. Of the total, 22 agents were detected killing trees on areas totaling larger than 5,000 ha each.
The more recent report does not discuss these declines from the 2017 findings or whether they might be related to the smaller percentages of forested areas covered by the aerial survey in 2018.
In both 2017 and 2018, as well as in the 20-year trend analysis (Chapter 6 of the report published in 2020), overall mortality is greatest in the West due to the impact of several native western bark beetles. Overall mortality rates in other regions was considered low, despite severe impacts of some non-native species.
The 2017 survey found that the emerald ash borer (EAB) was the most widespread single agent, causing measurable tree mortality on 1.42 million ha. In 2018, the area of EAB damage was reduced by 76% — to just 338,000 ha. (Still, the latter figure represented 15.8% of the total area displaying mortality). These figures were probably underestimates – especially in areas outside North Central Region – because EAB is one of the pests poorly detected by the aerial survey technique – at least when ash are growing scattered in a diverse forest ecosystem. Although the USFS report doesn’t say so, this decline probably reflected the collapse of dead ash trees and reduction in numbers of still-alive but vulnerable ash trees as the EAB invasion wave matured.
The reports document a huge increase in mortality attributed to the sudden oak death pathogen between 2017 and 2018. (SOD is the only widespread non-native agent of mortality on the West coast.) The area affected increased nearly seven-fold – from 6,335 ha in the 2017 survey to 42,771 ha in the 2018 survey. This equated to causing mortality on 3.9% of the total Regional mortality area. This finding parallels finding reported by the California Oak Mortality Task Force. Note that SOD-related mortality was not detected by the aerial surveys until 2008 – 13 year or more after scientists working on the ground detected the presence of the then-unknown pathogen in the forests of California.
tanoak killed by Phytophthora ramorum on Big Sur peninsula photo by Matteo Garbelotto
Another alarming increase detected in 2018 was that of balsam woolly adelgid (BWA) in the Interior West. BWA-caused mortality was evident on 44,000 ha – 8.4% of the total area with mortality. BWA impacts were especially severe in central Idaho. There are several native pests in the same area. (See BWA write-up here.) BWA was first detected in Idaho in 1983 – 35 years earlier.
Geographic Hot Spots
The EAB caused the principal hot spots in the East. In the USFS North Central Region, 91% of the area suffering tree mortality in 2017 was attributed to the EAB. The EAB was also causing mortality across 10,346 ha (16% of the total areas suffering mortality) in the Northeast (especially Connecticut) and more than 5,000 ha in the South (especially Kentucky). (See my December blog for a discussion of the puzzling situation in several Great Plains ecoregions, where mortality was attributed largely to drought rather than either EAB or Dutch elm disease.)
Another mortality agent in the Northeastern Region was the European gypsy moth. In 2018, it was responsible for tree death on 31% of the total 70,000 ha affected area.
Another hot spot was in Hawai`i. In 2017, about 37,000 ha of mortality was detected. By 2018, the dead zone had increased to 46,000 ha – despite a 12% decrease in the area surveyed. In both years, the data collectors officially called the cause unknown. The reports’ authors stated that the probable cause was they rapid ‘ōhi‘a death fungi. (I ask why the surveyors did not state the cause since rapid ‘ōhi‘a death was identified on the Big Island in 2014.)
rapid ‘ōhi‘a death photo by J.B. Friday
Other non-native pests that affected more than 5,000 ha in the lower 48 states in 2017 were the BWA outbreak in the Northeast (20,758 ha, primarily in Maine); beech bark disease (12,222 ha, primarily in the North Central Region), and oak wilt (9,573 ha, primarily in the North Central Region and Texas).
In the Southern Region, mortality agents were detected on 1% or less of the forested area in 2017. In 2018, EAB-caused mortality was detected on 9.7% of the total 13,000 ha area experiencing mortality. An earlier gypsy moth outbreak had apparently calmed. I remind you that the report authors have conceded that laurel wilt and hemlock woolly adelgid are poorly detected by the survey technique.
eastern hemlock in Shenandoah National Park (Virgina)
DEFOLIATORS
The 2017 survey detected defoliation caused by 50 agents and complexes across the lower 48. These impacted 2.3 million ha. The 2018 survey identified six more defoliation agents and complexes (56), but they affected a much smaller area – about 1.72 million ha.
Unsurprisingly, the most widespread was the European gypsy moth. The data demonstrated the gypsy moth’s boom/bust cycle. In 2017, gypsy moth impacts were detected on 39% of the total forested area of the lower 48 states (913,000 ha) in 2017. By 2018, the total area affected by the gyspy moth had fallen to 156,000 ha.
In both years, gypsy moth defoliation was particularly severe in the Northeast Region. In 2018, a second non-native species, browntail moth (Euproctis chrysorrhoea) was also causing severe defoliation in the region, primarily in Maine.
In the South, the European gypsy moth affected only 5.8% of the total area of defoliation; native defoliators predominated.
The report does not discuss the relationship between gypsy-moth caused defoliation and mortality. True, there must be repeated defoliations to cause tree mortality.
Other non-native defoliation agents affecting more than 5,000 ha in the lower 48 in 2017 were the larch casebearer (25,891 ha in the North Central Region and another 7,400 ha in the West Coast Region); and winter moth (12,760 ha in the Northeast Region). Is the decline of winter moth in 2018 data related to introduction of a biocontrol agent?
In 2018, the Larch casebearer (Coleophora laricella) continued to be a significant defoliator, affected 3.1% of the North Central Region’s total defoliated area. A new agent, the balsam woolly adelgid (BWA), was detected defoliating firs in the West Coast Region. The affected area was 15,000 ha – 5% of the total affected area Again, there was no discussion of as to whether defoliation precedes mortality. Admittedly, the progression of BWA damage in firs is extremely complicated.
Alaskan forests suffered widespread defoliation, mostly by native species. The survey detected an unknown canker on quaking aspen (Populus tremuloides).
Twenty Years of Data: Trends
In addition to reporting on the 2018 survey, the more recent report contains an analysis (in Chapter 6) of data over 20 years. The analysis is intended to be used in analyses required under the Resource Protection Act (RPA). The RPA analysis uses the same set of Insect and Disease Survey data, although it groups them in four rather than five regions.
The authors grouped the annual data into four five-year windows (1996-2001; 2002-2006; 2007–2011; 2012-2016).
An overview comprising all mortality agents across the nation found a major “spurt” in area exposed to mortality-causing agents in 2002-2006. The 14.2 million ha was 4.5 times greater than the 3.1 million ha affected in the preceding 1997-2001 period. This was attributed, in part, to a sampling change. The mortality footprint fell slowly in later periods – to 9.9 million ha in 2007-2011 and 6.9 million ha in 2012-2016. Other than during the 2002-2006 period, mortality was relatively low in the Northern Region – despite EAB – especially when compared to high mortality in the Rocky Mountain and Pacific Coast Regions attributed to bark beetles.
The mortality area attributed to pathogens was also highest in 2002-2006. This was due to three pests: a root diseases-bark beetle complex killing subalpine fir, oak wilt, and beech bark disease.
Very little disease mortality was reported in the South during any of the five-year periods – an alarming failure given damage to redbay by laurel wilt. The lapse is more confusing because past IDS reports have listed redbay as heavily damaged (see USDA FS FHTET 2014).
The Pacific states saw a modest increase over time. The sudden oak death infestation was first detected by the IDS survey in 2008 – approximately 13years after it was detected on the ground.
Over the 20 years, non-native species caused mortality on an average of 500,000 ha in each five-year period except 2002-2006 (described above). The proportion of the total mortality footprint associated with non-native species was14.8% in 1997-2001, 34.4% in 2002-2006, 3.6% in 2007-2011 & 7.4% in 2012-2016.
Only in the Northern Region was a large proportion of the mortality footprint consistently attributed to non-native species – 35.1% in 1997-2011 to 98.5% in 2002-2006. The suite of species changed over time. In the first period (1997-2001), the principal species were beech bark disease, European gypsy moth, oak wilt, and hemlock woolly adelgid. During two periods – 2002-2006 and 2007-2011 – those present earlier were joined by BWA, EAB, and Dutch elm disease. By the final period – 2012-2016 – the principal agents were EAB and red pine scale.
beech bark disease Photo by Linda Haugen courtesy of Bugwood
Non-native mortality agents detected in the South included hemlock woolly agelgid and oak wilt. HWA affected 71.8% of the affected area in 2006 – 2012, 21.9% in 2012-2016. EAB was first detected by the aerial survey in 2016.
In the two western regions, non-native agents had low footprints. The highest impacts were associated with BWA and white pine blister rust in the Rocky Mountain Region, Port-Orford cedar root disease and SOD in the Pacific Region, with the addition of BWA in some years and ROD in 2015 and 2016.
Generally, woodborers have caused the highest mortality levels, seconded by pathogens. Only in the 2002-2006 period did another insect feeding guild exceed 10% of total mortality area – when BWA (a sap feeder) reached 18.7% of detected mortality – on balsam fir in Maine.
In the Western regions, the disease white pine blister rust was second to the subalpine fir mortality complex. Even this ranking fails to reflect widespread mortality of lower-elevation five-needle pines in previous decades.
In the Northern Region, a disease – beech bark disease – was most important in the first five-year period. It was replaced by a wood-boring beetle – EAB. I have noted the importance of the BWA (a sap-feeder) infestation during 2002-2006.
In the Southern Region, native bark beetles usually predominated. There were outbreaks of the foliage-feeding European gypsy moth in2007-2011 and hemlock woolly adelgid (sap-feeder) in 2012-2016.
The authors of the report note that the South might be underrepresented for several reasons – but without mentioning the severe impacts on the understory trees redbay and more recently sassafras.
SOURCES
Bailey, R.G.. 1995. Descriptions of the ecoregions of the United States. 2d ed. Miscellaneous Publication No. 1391. Washington, D.C.: U.S. Department of Agriculture Forest Service. 108 p.
Fei, S., R.S. Morin, C.M. Oswalt, and A.M. 2019. Biomass losses resulting from insect and disease invasions in United States forests
Guo, Q., S. Feib, K.M. Potter, A.M. Liebhold, and J. Wenf. 2019. Tree diversity regulates forest pest invasion. PNAS. www.pnas.org/cgi/doi/10.1073/pnas.1821039116
Morin, R.S., K.W. Gottschalk, M.E. Ostry, A.M. Liebhold. 2018. Regional patterns of declining butternut (Juglans cinerea L.) suggest site characteristics for restoration. Ecology and Evolution.2018;8:546-559
Morin, R. A. Liebhold, S. Pugh, and S. Fie. 2019. Current Status of Hosts and Future Risk of EAB Across the Range of Ash: Online Tools for Broad-Scale Impact Assessment. Presentation at the 81st Northeastern Forest Pest Council, West Chester, PA, March 14, 2019
Potter, K.M., B.S. Crane, W.W. Hargrove. 2017. A US national prioritization framework for tree species vulnerability to climate change. New Forests (2017) 48:275–300 DOI 10.1007/s11056-017-9569-5
Potter, K.M., M.E. Escanferla, R.M. Jetton, and G. Man. 2019a. Important Insect and Disease Threats to United States Tree Species and Geographic Patterns of Their Potential Impacts. Forests. 2019 10 304.
Potter, K.M., M.E. Escanferla, R.M. Jetton, G. Man, and B.S. Crane. 2019b. Prioritizing the conservation needs of United States tree species: Evaluating vulnerability to forest insect and disease threats. Global Ecology and Conservation. (2019)
USDA Forest Service. Forest Health Monitoring: National Status, Trends, and Analysis 2018. General Technical Report SRS-239. June 2019. Editors Kevin M. Potter Barbara L. Conkling
USDA Forest Service. Forest Health Technology Enterprise Team. 2014. 2013-2027 National Insect and Disease Forest Risk Assessment. FHTET-14-01
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
We know that people moving firewood long distances is cause for great concern because of the likelihood that tree-killing pests will be transported to new and previously uninfested locations. This concern has been heightened by the USDA APHIS proposal to deregulate the emerald ash borer (EAB). As the principal federal “quarantine pest” transported by firewood, the EAB provides the legal foundation for most federal and state firewood regulations. (Of course, the EAB regulations also govern other articles that could transport wood-boring pests). (See earlier blogs here and here.)
Most forest pest professionals agree that the greatest risks are associated with individuals who transport firewood for recreational camping or summer homes. These people have proven to be the most difficult to regulate and the most likely to not see – or to ignore – messages intended to discourage them from moving firewood. The Nature Conservancy manages the “Don’t Move Firewood” program. It has done polling on messages and impact and concludes that the percentage of U.S. voters who have heard a “don’t move firewood” message remains steady and that those who have heard that message are less likely to transport firewood, especially over distances greater than 50 miles. More details are here
A recently published study by several academics and one forest service scientist reinforces The Conservancy’s earlier conclusion about the importance of outreach efforts as an essential component of programs intended to manage wood-boring pests. On the other hand, the new study points to additional nuances in crafting messages that will be effective in changing people’s behavior.
Findings
Daigle et al. 2018 (see full citation at the end of the blog) surveyed 272 people who were camping in public (state) or private campgrounds in three New England states in 2013 – four years after each of those states adopted regulations prohibiting out-of-state firewood and began their outreach efforts. Some campers apparently feel a strong connection to the place they are visiting, as shown by the fact that 84% of the 79 campers at private campgrounds had spent two or more nights camping in the same state in the previous year. That emotional connection might provide a motivation that could be activated to persuade those campers to stop transporting firewood (see below).
The authors found that slightly more than 25% of the 272 respondents reported that they often or always brought firewood from home for camping. More discouraging is that they found that people might not comply even when informed about the risks. Instead, compliance depended largely on the individual’s motivation and commitment level rather than knowledge. Worse yet, campers categorized as “highly involved” in the forest pest issue were just as likely to transport firewood from home as were others. Apparently, these non-compliant campers did not fully “connect the dots” between their concerns about forest health and their own actions. See below for Daigle et al.’s suggestions for ways to help people make those connections.
To understand the role of motivation, Daigle et al. tried to assess the strength of each camper’s beliefs about the relationship between tree-killing pests and the transport of firewood by recreational campers.
Overall, 25% of respondents were very highly involved with tree pest issues; another 22% were highly involved. Respondents’ perception of the relationship between damaging tree pests and transport of firewood differed significantly based on their levels of involvement. Respondents with a low level of involvement were less likely to agree with three statements (listed below) that firewood-associated pests pose a serious threat. Campers with very high levels of involvement strongly disagreed with three other statements that either downplayed the threat or portrayed the respondent’s compliance as “useless” as long as others continue to transport firewood.
Perception questions against which respondents’ agreement or disagreement was measured:
“There is not much one individual can do about invasive pests brought in by firewood”
“I don’t think invasive pests brought in by firewood are very important.”
“The threat of invasive pests brought in by firewood is serious.”
“As long as other people continue to bring firewood from home, my efforts to prevent invasive pests are useless.”
“The invasive forest pest risk from firewood is exaggerated.”
“In the long run, things will balance out with invasive pests.”
Rationale
Respondents’ most frequent explanations for why they take firewood from home when they go camping were cost, quality, and convenience. The most frequently cited reason for not transporting firewood was that the respondent knew that it was not allowed.
Level of pest awareness:
While nearly all respondents (92%) had heard something about non-native pests killing trees, but 57% could not recall the name of a specific pest in the absence of a prompt. When asked about the emerald ash borer and Asian longhorned beetle, more respondents had heard about the ALB (77% v. 52%). Most said the principal source of information was a state agency.
Suggested Actions
Daigle et al. conclude that authorities need to increase citizens’ exposure to outreach materials in order to activate concern and bring about desired actions to curtail risk of pests in firewood.
One clear need is to counter many campers’ belief that their wood is safe so it is okay to transport it regardless of the regulations. Often they based that belief on the fact that their home is not in a designated quarantine zone. Daigle et al. suggested that educational material should try to counter this belief by emphasizing the time lag between a pest’s establishment and its detection.
To help “connect the dots” between campers’ concerns about forest health and the implications of their actions (transporting firewood), survey respondents suggested using more visuals showing the destruction caused by the invasive forest pests, especially in areas they care about – close to home or favorite recreation areas. Daigle et al. thought such pictures would “help the campers with high involvement to trigger activation of attitudes with the association of forest pests and firewood transport.”
Other suggestions for strengthening outreach were to ensure that the message
Is novel – that it does not simply reiterate a camper’s initial belief system.
Produces agreement by the recipient without generating counterarguments.
Is relevant to the audience’s concerns.
They also suggested that campgrounds (public and private) help motivate campers to leave firewood at home by coordinating with local firewood vendors to provide competitively priced firewood at the campground or by including the cost of providing some firewood in the camping fee.
Daigle et al. made two other suggestions that call for stronger actions.
First, they suggested that outreach programs incorporate incentives or rewards to engage people who don’t have a high level of involvement in forest health issues.
Second, they suggested that authorities reinforce the educational message by using “more direct” actions, such as
confiscating illegally transported firewood at check stations,
issuing warnings about such actions, or
administering fines for moving non-compliant firewood.
The authors suggest that state agencies should consider taking these actions – but I see no reason why federal agencies should not also.
EAB; David Cappaert
Conclusions re APHIS’ Proposal to Deregulate EAB
Daigle et al. conclude that outreach efforts aimed at curtailing movement of firewood need to be continued. They are a critical component of overall management programs targetting non-native tree-killing pests – programs developed through decades of research and trials. The motive is clear: more effectively delaying these pests’ spread provides large benefits to municipalities and homeowners.
These are the same points made by many who opposed APHIS’ proposal to deregulate the emerald ash borer.
In its comments to APHIS, The Nature Conservancy noted that the domestic EAB quarantine had been effective in limiting spread of the pest through two of the most important pathways – firewood and nursery stock. The resulting slower spread had protected three-quarters of the ash range in the United States and bought time to develop mitigation measures.
Further, eliminating the federal quarantine would not only unleash this pathway for long-range movement of EAB but undermine the many federal, state, regional, tribal, private, and non-profit partners’ efforts to curtail movement of all invasive forest pests in firewood.
Many other commenters, including several state agencies, the National Association of State Foresters and Southern Group of State Foresters called for APHIS to continue leading national efforts to curtail spread of EAB and other pests through careless movement of infested firewood. The Montana Department of Natural Resources and Conservation and NASF specifically urged that APHIS reinstate the National Firewood Task Force (which APHIS led in 2009-2010).
The Don’t Move Firewood program has a more informal blog on this topic, available here.
Source
Daigle, J.J., C.L. Straub, J.E. Leahy, S.M.De Urioste-Stone, D.J. Ranco, N.W. Siegert. How Campers’ Beliefs about Forest Pests Affect Firewood Transport Behavior An Application of Involvement Theory. Forest Science XX(XX):1-10 https://academic.oup.com/forestscience/advance-article/doi/10.1093/forsci/fxy056/5232804
USDA APHIS released its Strategic Plan for fiscal years 2019-2023 just after Thanksgiving. The report is 21 pages long. There is no evidence that any stakeholders were asked for input or review.
The Plan has a disappointing – but not surprising – emphasis on deregulation and “customer service”. A second – and more surprising weakness is the lack of attention to plant pests – even those of agriculture, much less natural resources. The emphasis is clearly on animal pests and diseases – including zoonotics.
APHIS’ mission is “To safeguard the health, welfare and value of American agricultural and natural resources.” To accomplish this mission, APHIS has set three goals:
Deliver efficient, effective, and responsive programs.
Safeguard American agriculture.
Facilitate safe U.S. agricultural exports.
Most references to protecting natural resources relate to finding more environmentally sensitive approaches for the program under which APHIS reduces human-wildlife conflicts (e.g., birds being struck by airplanes).
In the Plan, APHIS Administer Kevin Shea writes in his opening message that achieving APHIS’ difficult mission of protecting the health and value of America’s agriculture and natural resources cannot be accomplished by APHIS alone. Instead, the agency must work collaboratively with other government agencies and industry, and consult regularly with partners and stakeholders regarding programs’ effectiveness. Administer Shea also highlights the importance of “delivering our programs and services efficiently, effectively, with integrity, …” The agency promises to modernize information technology, data management, methods of communication with collaborators, exporters and importers, etc., in order to give good return on expenditure of taxpayer resources. APHIS also pledges to make decisions based on science. There are seven references to basing decisions on scientific data.
Fair enough. Such emphases were to be expected from Trump Administration and prefigured by USDA Secretary Sonny Perdue during his nomination hearing, e.g., facilitating exports, supporting better information technology.
However, the Plan refers to “customer service” or “customer experience” 34 times. An additional seven references are made to reducing regulatory burdens. The Plan also speaks of the need to “protect the health, welfare, and value of American agriculture and natural resources. … at a reasonable cost. … Easing regulatory burdens makes it easier to create jobs and promote economic growth.” (Emphasis added.)
Perhaps the recent proposal to deregulate the emerald ash borer is driven in part by the emphasis on minimizing costs to regulated industries and seeking alternative approaches? (Although the deregulation has been under discussion for several years, predating the Trump Administration.)
from APHIS PPQ website
The imbalance in attention to animal versus plant pests and disease is striking. Each of the 14 goals is supported by a number of specific tactics. There are a total of 100 “tactics” under the two goals most directly relevant to preventing or managing pest introductions. These goals are: “Protecting America’s agriculture” and “Promoting U.S. agricultural exports.” Of the 100 tactics, only ten are clearly related to plant pests; 19 are pretty clearly activities that apply to both plant and animal pests and diseases; and five are unclear as to whether they include plant pests as well as animal diseases. Thus, only a third of the tactics apply!
[In making this calculation, I did not include 43 tactics listed under the first goal (“Deliver efficient, effective, and responsive programs”) or three objectives under the goal of “Protecting American agriculture” that apply explicitly to wildlife management, regulating genetically engineered organisms, or ensuring humane treatment of animals.]
Specific examples of such lack of balance include the six examples illustrating the declaration (on p. 4) that “Pest and disease events are more frequent, more complex, and less predictable.” Five of the examples are animal diseases, the sixth is the insect-vectored human disease caused by the Zika virus.
In discussing its efforts to balance its safeguarding efforts against increasing requests for market access by international trading partners, APHIS mentions some activities pertinent to plant as well as animal pest management, e.g., examining disease and pest risks and inserting mitigation strategies into international agreements and interstate movement protocols. However, the only specific action it mentions is helping countries to build capacity to implement the Global Health Security Agenda.
The only reference to forest pests is under one of the 24 tactics associated with Goal 2. Safeguard American agriculture, Objective 2.1: Prevent damaging plant and animal pests and diseases from entering and spreading in the United States to promote plant and animal health. This tactic calls for strengthening the North American perimeter against pest threats from outside the region to prevent introduction of agricultural, forest, and other invasive pests.
Why are Plant Pests slighted?
Perhaps plant-related efforts were left out because they are less “sexy”? Or because they are more distantly linked to human health? The Plan does state that “The tactics in this plan represent only a portion of APHIS activities and by no means embody all the important work APHIS does to fulfill its mission.”
Who knows what was left out?
How will adoption of this strategy affect future efforts to address tree-killing insects and pathogens – both those already present in the country and those yet to be introduced?
Might PPQ Fill in the Gaps?
In 2014 APHIS Plant Protection and Quarantine issued its own strategic plan. This supplementary plan made frequent mentions of safeguarding natural resources. Indeed, the third of the plan’s seven goals stated:
Goal 3: Protect forests, urban landscapes, rangelands and other natural resources, as well as private working lands from harmful pests and diseases
Several “tactics” under each goal also directly applied to protecting natural resources. I list them below:
1) Prevent the entry and spread of ag pests and diseases.
Coordinate with Canada to implement an effective multi-national system that reduces the threat of tree pests arriving from Asia and other parts of the world (e.g. AGM).
3: Protect forests, urban landscapes, rangelands and other natural resources, as well as private working lands from harmful pests and diseases
Maintain EAB regulatory framework to focus on the leading edge of infestations while minimizing impacts on regulated businesses in quarantined areas.
Evaluate the effectiveness of biocontrol releases in states and combining both regulatory & outreach activities to address the risks of moving logs, firewood, and nursery stock.
Examine detection technologies and partnering with states to determine and apply the most effective strategies to survey & eradicate the Asian longhorned beetle
Partnering with federal and state agencies to enact measures such as a public outreach campaign to mitigate the movement of forest pests through firewood.
Ensure the safe trade of ag products, creating export opportunities for U.S. producers
play a leadership role in revising ISPM#15
Protect the health of U.S. agricultural resources, including addressing zoonotic disease issues and incidences, by implementing surveillance, preparedness and response, and control programs
Strengthen partnerships with Tribal Nations to develop a robust surveillance and early detection system for detecting and reporting invasive species.
Work with all stakeholders to coordinate all-hazards agriculture and natural resources response support.
Develop science-based programs in collaboration with industry and academia to jointly identify practices that will mitigate pest damage. E.G., SANC program http://sanc.nationalplantboard.org/ [a Systems Approach to Nursery Certification] implemented jointly with the National Plant Board and nursery industry
Dare we hope that PPQ adopts an updated strategic plan that fills in some of the gaps in the overall APHIS plan?
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.
Kelly Church (Grand Traverse Band Ottawa Chippewa) with baskets she wove from black ash
As you know, in September APHIS published a proposal to alter management of the emerald ash borer (EAB). Under the proposal, APHIS would no longer regulate movement of firewood, nursery stock, or other items that can transport EAB to new areas. Instead, APHIS proposed to rely on biological control to reduce impacts and – possibly – slow EAB’s spread. I have posted two blogs about the weaknesses of the underlying analysis and the decision by the Center for Invasive Species Prevention to oppose the proposal. The proposal, accompanying “regulatory flexibility analysis,” and 150 comments by the public are posted here.
The Don’t Move Firewood program has provided links to the individual organizations’ comments here.
Here I summarize major points made by those commenting on the proposal.
Most state agriculture departments accepted the proposal. Few commented at all, leaving that to the National Plant Board. The NPB letter consisted of only four paragraphs. In contrast, several state forestry agencies commented.
Several organizations, including the National Plant Board and AmericanHort, agreed with APHIS that the quarantine has not worked primarily because detection tools are so poor. As a result, EAB is able to firmly establish for several years and spread in a new area before authorities detect it and take action.
It is clear from the comments that deregulating EAB might save APHIS money and effort, but the action will exacerbate the already substantial burden on many other U.S. entities – ranging from federal agencies such as USDA Forest Service and National Park Service to homeowners; woodlot owners to (potentially) exporters of all sorts of products; to Native Americans. The economic components of this potential burden surely deserve more serious evaluation as required under several Executive orders.
Comments Categorized
1) The quarantine has slowed the spread of EAB and it remains valuable in granting communities time to prepare
Several of the commenters wished to counter the proposal’s inference that quarantines had failed; rather, they insisted that quarantine has slowed spread of the EAB and that this strategy is still valuable because it gives un-infested areas more time to prepare. Those voicing this view included the National Association of State Foresters; Maine Department of Agriculture, Conservation and Forestry; Montana Department of Natural Resources and Conservation; Fond du Lac Band of Lake Superior Chippewa in Wisconsin; several bands of Native Americans in Maine (Houlton Band, Penobscot, an individual member of the Penobscot); The Nature Conservancy; a man who is both park superintendent for the City of Kalispell, Montana and Chair of the Montana Urban and Community Forestry Association; three local conservancies in Oregon (West Multnomah Soil and Water Conservation District; Four-County Cooperative Weed Management Area from Clackamas, Clark, Multnomah and Washington counties in the greater Portland Metro area; Tualatin Soil and Water Conservation District); Jefferson County Colorado Invasive Species Management team; Maine Mountain Collaborative; Blue Hill Heritage Trust of Maine; a small woodland owner in Maine; and a Professor in the School of Forest Resources at the University of Maine.
Oregon’s Department of Environmental Quality Water Quality Division opposed the APHIS proposal. The Division noted that EAB spread in the east was facilitated greatly by the continuity of ash habitats whereas ash habitats are much more patchy in the West. Given this situation, human transport is the most likely means by which EAB will reach the West – either from infested portions of the U.S. or via trans-Pacific trade.
A few entities that supported APHIS’ proposal – e.g., the Southern Group of State Foresters and – in a separate letter – Texas Forest Service – also said the quarantine had been helpful.
As The Nature Conservancy said in its comments, the quarantine effectively limits two of the most important pathways, firewood and nursery stock. The result has been to protect much of the country from the pest and buying time to develop mitigation measures.
2) APHIS’ dismissal of quarantine is a worrying message (see also discussion of firewood below)
Several of the commenters expressed concern that APHIS too curtly dismissed the value of quarantine – both as it functioned to slow spread of EAB and as a tool used against a wide range of pests. Commenters raising issues about the proposal’s apparent undermining of quarantine as a strategy included the Kansas Forest Service; Maine Department of Agriculture, Conservation and Forestry; Vermont Agency of Agriculture, Food and Markets and the Department of Forests, Parks, and Recreation; and Wisconsin Department of Natural Resources Division of Forestry. The Vermont and Wisconsin agencies asked APHIS to clarify to affected parties what it expects to achieve by the proposed deregulation. The Fond du Lac Band of Chippewa warned that the public might interpret the dropping of regulations as signaling that EAB is no longer important.
Five organizations unified under the banner of the Coalition Against Forest Pests noted that APHIS had set a precedent of dropping regulations when quarantines appear to fail.
A subset of these comments focused on a lack of clarity by APHIS as to its future strategy.
Several commenters said that APHIS had not outlined a coherent strategy for the future. The Kansas Forest Service even called the proposal an agency “exit strategy” rather than a coherent plan. Others raising this issue included the Maine Department of Agriculture, Conservation and Forestry; South Dakota Department of Agriculture and Department of Game, Fish and Parks; and the Coalition Against Forest Pests. Maine noted that the proposal would shift the burden of regulation to the states. Maine and South Dakota said that APHIS, as the responsible federal regulatory agency, should provide a clear and consistent process for regulation of potentially infested products across state lines.
The Tennessee Forest Health Coordinator called for an analysis of EAB program successes that might point to ways in which APHIS could support alternative strategies. A professor of forestry in Maine said APHIS should evaluate and assess techniques specifically to optimize the effectiveness of education and outreach.
Among entities which supported APHIS’ proposed new approach, the Southern Group of State Foresters, Texas Forest Service, and two Vermont agencies – Agency of Agriculture, Food and Markets and the Department of Forests, Parks, and Recreation – urged APHIS to champion a national, multi-agency approach to managing EAB, including creation of a national, voluntary treatment standard and label for firewood; redirecting all savings to research & management – including state surveys. These groups also advocated funding increases for APHIS, the USDA Forest Service, and state EAB programs; and support for states to carry out their enlarged responsibilities for survey, outreach, education, and assistance to affected parties.
The Vermont agencies wrote that EAB “is a nationally significant pest, … which warrants a significant federal role.” Because EAB impacts on communities, forest health, and the forest economy continue to expand, a decision to discontinue regulatory activities should be accompanied by increased federal support for research and management.
The National Association of State Foresters also called for APHIS to champion a national, multi-agency approach, with a somewhat longer list of components. These should include support state research and management efforts, the biocontrol program, identifying genetic strains of ash trees that are resistant to EAB, maintain national treatment criteria for wood products (including firewood), and reconvene the National Firewood Task Force. NASF also urged the USDA Forest Service to develop a cooperative management program to sustain and replace ash trees killed by EAB.
Dr. David Orwig of Harvard Forest also called for funding not just biocontrol but also research areas like silviculture, chemical control, ash utilization, and management guidelines.
This pattern of asking for continued or expanded federal engagement – beyond biocontrol – is quite apparent. Some entitites that said they supported APHIS’ proposal nevertheless called for the agency to continue detection and response components of the program – expressly contrary to the proposal itself.
Thus, AmericanHort, the two Vermont agencies, Wisconsin Department of Natural Resources Division of Forestry, and two Maine departments called for APHIS to continue or increase its engagement in EAB detection and other management activities – including biocontrol, outreach to explain the change in strategy, and engaging the National Park Service and Forest Service in promulgating a consistent firewood policy.
Others who asked for similar commitments were straightforward in opposing the proposal. Thus the North Dakota Department of Agriculture and North Dakota Forest Service – in separate letters – asked that APHIS continue to provide resources to help states monitor EAB presence and respond to any new detections. The Oregon Department of Forestry asked that federal agencies continue to fund research and development of early detection and rapid response strategies for EAB; conservation of ash genetic resources and promotion of natural resistance; research on uses of dead ash; as well as classical biocontrol once EAB is established in a new area.
Several commenters said that they had considered APHIS to be a critically important partner in countering the EAB and were disappointed that the agency is backing away. Native Americans in particular considered the proposal to be a betrayal of the Federal government’s treaty responsibilities vis a vis recognized tribes. The Fond du Lac Band of Wisconsin wrote that upholding a federal EAB regulation is vital to the protections of important cultural and natural resources both on the Reservation and within territories ceded to the Band by several 19th Century treaties. The tribe cited EO 13175 issued by President Clinton. The Houlton Band of Maine said APHIS has a mission to defend federally recognized tribes against invasive species. The federal government should not make a decision so contrary to its fiduciary trust responsibility to federally recognized tribes.
3) Need for continued APHIS leadership on firewood regulation
The importance of APHIS continuing to lead national efforts to curtail spread of EAB (and other pests) through careless movement of infested firewood was stressed by many commenters. Voicing this need were many of the entities which opposed the proposal, including Maine Department of Agriculture, Conservation and Forestry; Montana Department of Natural Resources and Conservation; Southern Group of State Foresters; Texas Forest Service; the two Vermont agencies; The Nature Conservancy; and the National Association of State Foresters. As noted above, the NASF, Southern Group, Texas, and Vermont all said APHIS should support creation of a national, voluntary treatment standard & label for firewood. TNC said eliminating the EAB quarantine – the best known and understood firewood regulation – will exacerbate difficulties of outreach. Public outreach and education work best when they are backed up by core consistent rules. Montana Department of Natural Resources and Conservation and NASF called for reinstating the National Firewood Task Force (which APHIS led in 2009-2010).
Several entities that supported the proposal also called for continued APHIS engagement on firewood. One, the Wisconsin DNR Division of Forestry, urged APHIS to work with the National Park Service and Forest Service to create a consistent firewood policy. A second, the NPB, noted that it is developing guidance to states interested in initiating regulations, best management practices, or outreach programs. The NBP added that it welcomes any assistance from APHIS.
As The Nature Conservancy and Tennessee Forest Health Coordinator pointed out, the firewood effort – federal regulations, state regulations, education and outreach under the “Don’t Move Firewood” campaign – all helped curb movement of several tree-killing pests, not just EAB.
4) Others Pointed Out the Importance of Consistent Regulations to Keep Markets Open
A smaller number of entities addressed the similar importance of consistent rules governing interstate and US-Canadian trade in other types of vectors that can transport EAB and which are to be deregulated under the proposal. These included the NASF. Several private groups from Maine and the Maine Department of Agriculture, Conservation and Forestry noted the importance of reaching agreement with Canada, which is a major market for their wood products. The two South Dakota departments also expressed concerns.
The National Wooden Pallet and Container Association raised the prospect of truly tremendous disruption of trade. At present, the United States and Canada exempt wood packaging originating in either country from requirements that it be treated in accordance with international standards (ISPM No. 15). Canada has many reasons to fear that crates and pallets carrying exports from the U.S. might be infested by EAB once APHIS stops enforcing quarantine regulations. If Canada responds by ending the exemption and requiring wood packaging from the U.S. to comply with ISPM#15, that action would affect a wide range of U.S. exports – from fruits to auto parts. In 2017, the U.S. exported $282 billion worth of goods to Canada (Office of the U.S. Trade Representative)
5) The Economic Analysis Underlying the Proposal was Inadequate
Several commenters criticized the adequacy of the economic analysis. The most specific criticisms were put forward by the California Forest Pest Council; CISP; the five organizations commenting under the banner of the Coalition Against Forest Pests; and the National Wooden Pallet and Container Association. The latter two cited specific Executive orders and the Paperwork Reduction Act in calling for a review of the proposal by the Office of Management and Budget & USDA Office of General Counsel to reassess whether it meets the conditions for the reduced economic analysis. As noted above, the NWPCA mentioned specifically a fear that Canada might discontinue the mutual exemption under which wood packaging may move between the two countries without being treated in accordance with ISPM#15. The possibility of such an action would certainly push the proposal over the $100 million threshold for completing much more rigorous economic analyses.
Other economic concerns not adequately addressed in the view of the commenters relate to costs arising earlier due to the faster spread of EAB to un-infested western states. Costs imposed earlier than would otherwise be the case are considered relevant in regulatory decisions. Furthermore, businesses in these and possibly other states will face new regulations adopted by states to fill the void left by federal deregulation. Finally, the lack of consistency arising from separate state regulations will impede interstate or US-Canada commerce.
Non-regulatory costs – death of trees and associated removal costs – costs to the forest industry, plus municipalities and home owners in areas not currently affected by infestation – were also not discussed in the proposal.
Several commenters said that APHIS had underestimated the ecological and cultural values threatened by spread of EAB. These included the Fond du Lac Band, Penobscot band, TNC, the Oregon soil conservation district and weed management area; Maine Mountain Collaborative and Woodland Owners, as well as several individuals.
The Nature Conservancy noted that three-quarters of the native ash range of the conterminous United States and 14 of vulnerable species in the U.S. and Mexico are still free of EAB as a result of the quarantine.
A Minnesota community’s Parks Commission noted that loss of trees to EAB can lead to other problems and costs. Consequently, the goal of “saving money” will not be achieved. In short, EAB-caused tree mortality “affects communities, including residents, homeowners, and taxpayers. Funding should be directed both to slowing the spread of the pest and to treatment of affected trees.”
A small woodland owner in Maine asked why APHIS did not evaluate economic impacts to landowners & municipalities.
Oregon’s Department of Environmental Quality Water Quality Division added that pesticides used to control EAB might cause negative impacts in riparian and aquatic environments.
6) Several Commenters questioned whether freed-up funds would support biocontrol – or whether they should
As noted in my earlier blogs, there are questions about whether biocontrol will be efficacious in protecting forests across the continent. CAFP echoed these questions. Blue Hill Heritage Trust of Maine called biocontrol experimental.
The Fond du Lac Band pointed out that most tribes don’t accept biocontrol on their reservations – so spending all available funds on this approach doesn’t help Native Americans.
The Maine government and the Penobscot Band of Maine expressed doubt that increased funding would actually materialize.
7) Comments that do not fit neatly into these categories.
The California Department of Agriculture said that it intends to promulgate a state exterior quarantine to protect its agriculture (olive trees are hosts of EAB) and environment.
The South Dakota Department of Agriculture and Department of Game, Fish and Parks concluded that interstate regulatory options should be a higher priority than other methods of control.
The Houlton Band of Maine said that maintaining the domestic quarantine is the only federal action that can adequately address the universally agreed fact that human activities cause the rapid spread of EAB.
The Western Governors Association described the region’s vulnerability to EAB spread and, citing recent Association policy resolutions, said a decision of this magnitude should be made only after substantive consultation with Western Governors.
The National Association of State Foresters pointed out that a decline in federal funding for EAB detection surveys will significantly reduce state forestry agencies’ capacity to monitor and respond to EAB spread.
The Jefferson County, Colorado Invasive Species Management team recommended retaining the quarantine using either the 100th Meridian or Continental Divide as the containment boundary. It cited as a justifications the “culture of vigilance” created by strong quarantines. This vigilance saves financial resources and protects natural and agricultural resources.
Finally, the Fond du Lac Band of Lake Superior Chippewa said that abandoning methods that are in place for the prevention of EAB’s spread, such as federal and state quarantines, and favoring only options that focus on rehabilitating a site after it has undergone a severe infestation, presents a large and unnecessary ecological risk. Invasive species programs have always focused on “prevention” being the key.
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.
Several scientists at the United States Geological Service (USGS) have published a report and accompanying datasets that attempts to provide a publicly accessible and comprehensive list of non-native species established in United States.
Led by Annie Simpson and Meghan C. Eyler, a team of six scientists worked six years (2013–2018). They reviewed 1,166 authoritative sources to develop a list of 11,344 unique names – most of them binomials (genus and species), a few genera, plus some viruses.
This was a Herculean effort that produced very valuable products. We are all in their dept!
Simpson and Eyler point out that knowing which species are non-native to a region is a first step to managing invasive species. Lists compiled in the past were developed to serve a variety of purposes, including watch lists for preventing invasions, inventory and monitoring lists for research and modeling, regulatory lists for species control, and non-regulatory lists for raising awareness. As a result, they are not comprehensive.
Among the sources these authors consulted in preparing the list were peer-reviewed journal articles, books, brochures, circulars, databases, environmental assessments, technical reports, graduate theses, and websites.
Data – by Region
The report also notes which non-native species were established in each of three regions: the “lower 48” states, Alaska, and Hawai`i. Not surprisingly, more than half the non-native taxa are established in the vast area (nearly 7.9 million km2) comprising the “lower 48” states – 6,675 taxa. Almost half of the total number of non-native taxa have established in the tiny geographic region (only 28,311 km2) of Hawai`i – 5,848 taxa. One-tenth as many non-native taxa – 598 – are reported as established in Alaska (1.7 million km2).
This report includes taxa that are not native to any part of the specific region, but established (naturalized) somewhere in the region. An “established” species must have at least one population that is successfully reproducing or breeding in natural systems. The list includes domesticated animals and plants introduced for crops or horticulture when the taxon has escaped cultivation or captivity and become established in the wild. Species listed range from feral hogs (Sus scrofa) to plum pox virus and citrus canker to ohia rust (Puccinia psidii).
Of the total 11,344 taxa, 157 are established in all three regions. These included 125 vascular plants (especially grasses and asters); 13 arthropods, 11 mammals; 6 birds; 3 mollusks; 1 bryozoan. One of the ubiquitous plant species is tree of heaven (Ailanthus altissima). I find it entirely appropriate that the cover photo shows this tree – the photo was taken 8 miles from my home in Fairfax County, Virginia.
Nearly three-quarters (71.4%) of the non-native species in Alaska are plant species. More than half (59.7%) of the non-native species in the “lower 48” region are also plants. Nearly all the remainder of the non-native species in both regions are some kind of animal. Fungi constitute only 1.8% of the non-native species in the “lower 48” region; all the rest of the groups (Bacteria, Chromista, Protozoa, Virus) constitute less than 1% of the non-native species recorded in either region.
By contrast, in Hawai`i, animals make up 69.7% of the listed non-native species; most are invertebrates. Plants constitute 29.8% of the Hawaiian list.
Gaps, by Taxon
The authors recognize that invertebrates and microbes are under-represented because species are still being discovered; non-charismatic and difficult-to-identify species tend to be overlooked; and the species composition of any nation in this era of globalization is constantly subject to change.
I have noted some gaps among the pathogens: the absence of some of the Phytophthora that have been detected infecting shrubs and herbaceous plants in California, e.g., Phytophthora cambivora, siskiyouensis, tentaculata; and the “rapid ohia death” pathogens, Ceratocystishuliohia and C. lukuohia. Dr. Simpson is aware of these gaps and is soliciting sources to help add these organisms – especially the various Phytophthora species – to the next version of the list.
Simpson and Eyler note that the relative geographic distribution of the list at its current state seems to reinforce three well established premises: that tropical island systems are particularly vulnerable; that higher latitudes host fewer but are not invulnerable; and that species diversity in general decreases with increasing latitude.
Comparisons to Other Databases
After standardizing the names in the list by comparing them to the Integrated Taxonomic Information System (ITIS), Simpson and Eyler also reviewed the USGS BISON database, which has more than 381 million occurrence records for native and non-native species in the U.S. and Canada, covering 427,123 different taxa. (The BISON database contains significantly more species occurrences for the U.S. than the largest invasive species database, EDDMapS, which contained 4.4 million species occurrences as of June 2018.) Simpson and Eyler had to evaluate which of these taxa met their definition of non-native, since most species occurrence records in the USGS BISON are not labeled as non-native in the original records.
Comparing the BISON and non-native lists, Simpson and Eyler found that the BISON list contained a larger number of occurrence records for non-native taxa: a total of 13,450,515.However, the BISON list does not provide complete coverage of non-native species: it includes records for 77% of list of non-native species Simpson and Eyler found in Alaska, 75% of the “lower 48” sublist, but only 37% of the Hawaiian sublist.
Simpson and Eyler state their intention to continue updating the list of non-native species, they welcome contributions to it from area experts, and they urge integration of new occurrence data into invasive species database such as EDDMapS.
Indicators of Non-Native Species Richness
Figure 3 in the report (above) maps the number of non-native taxa in BISON at the county level. Figure 4 displays the proportion of non-native to native species in BISON. Higher percentages are generally evident in coastal areas and other regional hotspots. For example, the proportion in Hawaiian counties is greater than 33%. Additional data are needed to perform a more in-depth analysis of non-native species richness and abundance.
UPDATE! New Report in the Works
In June 2021, USGS announced that it was updating its Comprehensive List of Non-Native Species Established in 3 Major Regions of the U.S. so that the document more closely aligns with the parameters of the Global Register of Introduced and Invasive Species. The new USGS dataset is to be called the US Register of Introduced and Invasive Species. The list in the current draft includes 15,364 records. About 500 of these records are in Alaska, 6,000 in Hawai`i, and 8,700 in the conterminous 48 States.
One of the lead authors, Annie Simpson, contacted invasive species experts seeking feedback and suggested additions – based on authoritative resources such as peer reviewed journal articles, pest alerts, databases, books, and technical bulletins.She sought input by 25 July, 2021.
The published version of this dataset will be made freely available on USGS’ ScienceBase (https://www.sciencebase.gov), and all reviewers will be acknowledged in the dataset’s abstract.
SOURCE
Simpson, A., and Eyler, M.C., 2018, First comprehensive list of non-native species established in three major regions of the United States: U.S. Geological Survey Open-File Report 2018-1156, 15 p.
The report and accompanying data tables are available here.
South African report
In an unrelated but similar development, South Africa has issued a report on its invasive species — 2017 The Status of Biological Invasions and Their Management in South Africa. The report analyzes pathways of introduction and spread; number, distribution and impact of individual species; species richness and abundance of alien species in defined areas; and the effectiveness of interventions. The report notes that 775 invasive species have been identified to date, of which 556 are listed under some national regulatory program. Terrestrial and freshwater plants number 574 species; terrestrial invertebrates number 107 species. (This total does not include the polyphagous shot hole borer, which was detected too recently.) 107 species are considered by experts to be having either major or severe impacts on biodiversity and/or human wellbeing. Alien species richness is highest in the savanna, grassland, Indian Ocean coastal belt and fynbos biomes, lower in the more arid Karoo and desert biomes. South Africans are particularly focused on the reductions in surface water resulting from plant invasions. The decades-old “Working for Water” program has two goals: providing employment and development opportunities to disadvantaged individuals in rural areas, and managing invasive alien plants.
The Status of Biological Invasions and Their Management in South Africa is available here.
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.
Phytophthora cinnanomi killing Ione manzanita in California; photo from Swiecki and Garbelotto, Distribution of Phytophthora cinnamomi within the range of Ione manzanita (Arctostaphylos myrtifolia). Agreement between the California Department of Fish and Game and University of California
Phytophthora species are plant pathogens in the oomycote group (water molds, closely related to brown algae). More than 160 species have been described; new species are continually being isolated. Many Phytophthora species are deadly to naïve hosts; examples in the United States include sudden oak death, Port-Orford cedar root disease, disease on chestnuts and oaks.
Forests in Europe – especially the United Kingdom – and Australia are also suffering high levels of mortality associated with one or more Phytophthora species.
In recent years, several studies have documented the role of nurseries in spreading non-native Phytophthora species. Two strains of P. ramorum are widespread in European nurseries and in tree plantations and wild heathlands of southwest England, Wales, parts of Scotland, and Ireland. (See here and here.)
In April 2016 I blogged about the situation in Europe described by Jung et al. 2015 (see references at the end of the blog). Jung et al. concluded that diseases caused by Phytophthora pose a substantial threat to both planted landscapes and forest ecosystems across Europe. They found 56 Phytophthora taxa in 66% of 2,525 forest and landscape planting sites that were probably introduced to those sites via nursery plantings.
Barber et al. 2013 reported nine species of Phytophthora associated with a wide variety of host species in urban streetscapes, parks, gardens, and remnant native vegetation in urban settings in Western Australia. Phytophthora spp were recovered from 30% of sampled sites.
A new summary confirms that the threat is similar in North America. In British Columbia, Dale et al. (2017) found more than two times as many Phytophthora species were detected in soil and water samples in urban areas (23) than in natural areas (11). Urban samples also showed a much higher diversity of Phytophthora per site than natural environments. These Phytophthora species had been introduced initially into urban areas and had subsequently spread into native vegetation, particularly in areas near developed sites (wildland-urban interface areas).
Swiecki et al 2018 cite several sources and their own studies to show that the large and increasingly diverse contingent of introduced Phytophthora species pose an increasingly important threat to both urban forests and surrounding native forests and plant communities in California. It is clear that shrubs and herbaceous plants as well as trees are also at risk. These scientists have repeatedly found multiple non-native Phytophthora species at individual sites in northern and southern California sites where nursery stock had been planted. Sampling in 2014 identified about 60 different Phytophthora taxa in restoration planting sites and native plant nurseries. The sampled restoration plantings were mostly located in urban riparian corridors and peri-urban parks, open spaces, or protected watersheds.
I first discussed this issue in a blog in July 2016.
Swiecki et al (2018) have also found that Phytophthora species persist in drier ecosystems. When conditions are too dry for sporangium production, Phytophthora hyphae produce resistant survival structures that can tolerate drying and persist in dead root fragments or soil. In the presence of appropriate stimuli, e.g., moisture and root exudates, resistant structures germinate to produce sporangia or hyphae, leading to new infections. Even relatively short wet periods associated with rain or irrigation can be sufficient to stimulate zoospore release. Swiecki et al (2018) list examples of numerous Phytophthora infestations that developed in dry sites, such as dry foothills of the Sierra Nevada in Amador County, and the Oakland Hills of Alameda & Contra Costa County. Swiecki et al. (2018) also note that P. cinnamomi has persisted in Australian forests in the absence of known primary hosts.
Phytophthora infections can also persist for decades in soil. In California, Swiecki et al. (2018) mention several examples:
Residual cinnamomi inoculum killed young sprouts of susceptible manzanitas (Arctostaphylos myrtifolia and A. viscida) planted on sites that were infected many years earlier.
A street planting of cork oaks (Quercus suber) apparently died due to Phytophthora root rot that had occurred 21 years earlier.
Both cinnamomi and P. cactorum were recovered from roots and soil beneath affected trees at least 60 years after the site had been a municipal woody plant nursery and adjacent residence.
A 7-acre area of native vegetation showing decline & mortality of multiple plant species was infested with multiple Phytophthora spp, including cactorum, P. cambivora, P. crassamura, P. ‘kelmania’ & P. syringae. The site was apparently infected 22 years earlier during a planting of a habitat restoration project using Ceanothus nursery stock. Subsequent spread was primarily downhill from the planting sites, facilitated by water flow, with additional spread along and near trails.
The Risk from the Nursery Trade
While Phytophthora-infested soil and plant debris can be transported on tools, vehicles, and shoes, or moved in large quantities when infested soil is excavated, graded, or imported, the principal threat is the nursery trade.
Jung et al. (2015) state that widespread contamination of nursery stock was the primary means by which these pathogens were introduced and spread in Europe. They found 49 Phytophthora taxa in 670 European nurseries. Phytophthora species were recovered from more than 90% of the sampled nurseries.
Swiecki et al. (2018) say that most of the common Phytophthora species detected in California are distributed globally, moved about with live plants or other infested materials. None is native to California.
Swiecki et al. (2018) cite studies reporting that thirteen species of Phytophthora were found in a survey for leaf spots in California nurseries in 2005 and 2006. Sampling of plants in or originating from Calif native plant nurseries alone has yielded about 60 Phytophthora At least eight species of Phytophthora were found in shipments of symptomatic and asymptomatic plants sent from west coast nurseries to Maryland. Parke et al. (2014) identified 28 Phytophthora taxa in four Oregon nurseries.
Not all infections are on the West Coast. Swiecki et al. (2081) reports that a survey in Minnesota nurseries of plants with symptoms – primarily on aboveground plant parts – found eleven species of Phytophthora.
Are scientists in other parts of the country looking for Phytophthora? I see no reason to think the situation in California is unique.
The damage caused by Phytophthora infections can be significant. In California and Oregon, sudden oak death, and Port-Orford cedar root disease, have killed well over a million trees and disrupted the ecosystems of which they are a part. There are multiple locations in Northern California where introduced Phytophthora species, especially P. cinnamomi and P. cambivora, have caused localized to extensive decline and mortality in native forests and shrublands.
Phytophthoradieback has infected more than one million hectares in Western Australia. More than 40% of the native plant species of the region are vulnerable to the causal agent, P. cinnamomi.
Phytophthora dieback in Western Australia
Dieback in native forest in Western Australia; photo copyright Western Australian Department of Parks and Wildlife
In the United Kingdom, several Phytophthora species are causing widespread mortality of native shrubs and trees and commercial plantings.
In nearly all the studies, scientists have detected previously unknown pathogen-host relationships.
The threat from spreading pathogens with wide host ranges is not limited to the genus Phytophthora. The fungus Fusariumeuwallacea associated with the Kuroshio and polyphagous shot hole borers is known to kill at least 18 species of native plants in California and additional species in South Africa. The laurel wilt fungus kills many trees and shrubs in the Lauraceae family. ‘Ohi‘a or myrtle rust kills several shrubs native to Hawai`i and threatens a wide range of plants in the Myrtaceae family in Australia and New Zealand. Some insects also have wide host ranges, including the Kuroshio and polyphagous shot hole borers; and Asian longhorned and citrus longhorned beetles.
When are national and international phytosanitary agencies going to adopt policies and programs that are effective in preventing the continued spread of these highly damaging tree-killing pests? At the national level, APHIS needs to aggressively use two authorities to curtail importation of plant taxa from countries of origin which present a risk of transporting additional species of pathogens:
NAPPRA, which allows APHIS to prohibit risky imports until it has conducted a pest risk analysis.
Programs under the revised “Q-37” regulations allowing APHIS to work with exporting countries’ phytosanitary officials to implement integrated pest management strategies to ensure that plants are pathogen-free before they are exported.
I have blogged about both programs before – NAPPRA here; the Q-37 regulation strengthening here.
At the international level, the members of the International Plant Protection Convention (IPPC) must recognize the failure of the international phytosanitary system and explore ways to strengthen it. See my numerous blogs on this topic (beyond those linked to here!) by visiting www.cisp.us or www.nivemnic.us and searching under the category “forest pathogens”.
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.
SOURCES
Jung, T. et al. 2015 “Widespread Phytophthora infestations in European nurseries put forest, semi-natural and horticultural ecosystems at high risk of Phytophthora disease” Forest Pathology. November 2015; available from Resource Gate
Swiecki, T.J., E.A. Bernhardt, and S.J. Frankel. 2018. Phytophthora root disease and the need for clean nursery stock in urban forests: Part 1 Phytophthora invasions in the urban forest & beyond. Western Arborist Fall 2018
Apparently can’t access current (2018) issues of “Western Arborist” on web unless subscribe
I blogged about APHIS’ proposal to stop regulating movement of objects that can transport the emerald ash borer on 28 September. At that time, I and the Center for Invasive Species Prevention were undecided. Now we have taken a firm position: We are sympathetic to the situation in which APHIS finds itself and are disappointed that APHIS’ efforts against EAB have not been as successful as hoped. However, we believe the quarantine continues to serve a useful purpose in protecting North America’s ash (and through the firewood regulatory effort, other resources) and that the analysis APHIS provides does not justify the proposed termination of the regulatory program. Making this regulatory change, based on absent and questionable scientific data, would set a terrible precedent.
Problems Arising from Poorly Substantiated Proposal
Here I provide some additional information on points I made in the blog in September.
1) The APHIS documents are completely unbalanced. They provide no analysis of the economic or environmental impact of the regulatory changes that will allow the pest to spread more rapidly to the large areas of the country that are not yet infested.
The proposal concedes that emerald ash borer currently is known to occupy only about one quarter of the range of native Fraxinus species within the conterminous United States. As the Regulatory Flexibility Analysis states, numerous sawmills, firewood dealers, nurseries, logging/lumber companies, pallet manufacturing companies, and other establishments operate in these un-infested areas. The analysis makes no mention of the costs to millions of homeowners and property owners, thousands of municipal governments, etc., of removing and replacing ash trees on their properties that are killed by the ash borer as it spreads into new areas. The “analysis” makes no attempt to quantify impacts on any of these entities.
Examples of ash populations currently free of EAB include:
In North Dakota, 84% of the forest land area is dominated by hardwood forest types; one of the three major forest-type groups is elm/ash/cottonwood. Ash represent 38% of urban forest trees (Nowak, Hoehn, Crane, Bodine.)
In California, velvet ash (Fraxinus velutina) comprises 3.1% of the state’s street tree population (McPherson et al.). Because ash are large relative to other street trees, they provide about double the proportion of leaf cover (and associated environmental services) than the number of trees (Nowak, Hoehn, Crane, Weller, and Davila).
Portland, Oregon: ash represented 4% of urban trees (Portland Parks).
No mention is made of the additional range of Fraxinus species in Canada and Mexico that will be put at greater risk of invasion as the beetle spreads in the United States.
2) The proposal to rely on biocontrol to control EAB in the future lacks any scientific analysis of either the current biocontrol program’s effects or other possible program components.
APHIS is apparently relying on the conclusion by Duan et al. 2018 – based on models rather than field research findings – that larval and egg parasitism at about 60% would lead to a net population growth rate of EAB at a rate below replacement, therefore rapidly reducing EAB populations when such parasitism rates are accompanied by moderate to high levels of host plant resistance. If heavy woodpecker predation can be relied upon, a parasitism rate on EAB larvae of about 35% would be sufficient to achieve a similar reduction in the EAB population growth, even with limited levels of host resistance or tolerance.
However, scientific publications reviewing the impacts of the decade-old EAB biocontrol program present a mixed picture.
Our reading of several published studies indicate that two biocontrol agents (Oobius agrili and Tetrastichus planipennisi) appear to have established and spread in the northern reaches of the EAB’s U.S. range and southern Canada. At least some ash species appear to be regenerating well in some of those areas. However, it is too early to determine whether a third biocontrol agent (Spathius galinae) can protect the all-important remaining large trees, which have thicker bark. It is also too early to determine whether a different biocontrol agent (Spathius agrili) will have an impact on ash survival and regeneration in the middle latitudes (south of the 40th parallel).
APHIS does not discuss current or planned future efforts to seek and test biocontrol agents more likely to thrive in the South and West – to which EAB will spread. It is hoped – but not yet proved – that S. agrili will be more effective south of the 40th parallel. The article said nothing about possible agents that might be effective farther south or especially in the West.
Some scientists question the probable efficacy of biocontrol. For example, Showalter et al. note that “Despite the presence of a full complement of coevolved natural enemies in Asia, EAB has caused high mortality of North American ash species planted there … Biological control is best applied to systems in which the hosts can at least partially resist or tolerate non-native PIP [phytophagous insects and phytopathogens] attack, especially if negative density-dependent responses of natural enemies are slow relative to how long it takes the non-native PIP to kill trees.” Even Duan et al. 2018 agree that Asian ash species are more resistant (although they emphasize the large impact of natural enemies in Asia).
The scientific literature indicates that the impacts of egg parasitoid O. agrili remain uncertain (Abell et al.).
Duan et al. 2018 list and provide brief evaluations of nine possible biocontrol agents:
2: status not revealed (Sclerodermus pupariae, Atanycolus nigriventris)
2: disappointing efficacy to date (Spathius agrili, Oobius agrili)
1: apparently efficacious in some geographies in smaller trees only (Tetrastichus planipennisi)
1: promising in northern parts of EAB range but too early to evaluate (Spathius galinae)
2: considered to have too broad a host range to be released (Tenerus, Xenoglena quadrisignata)
1: release delayed pending further study (Oobius primorskyensis)
Even the impact of the most promising agent, Tetrastichus planipennisi, is not altogether clear. Duan et al. 2018 cite their life table analyses as indicating that T. planipennisi has contributed significantly to reducing net EAB population growth rates. They note a 90% reduction in EAB larval density. However, they say that this decline might be attributed in part to either the impact of the parasitoid or the general collapse of EAB populations following widespread mortality of overstory ash. (emphasis added)
3) Neither the proposal nor the supplementary materials provides any information about the current allocation of available funding among APHIS’ program components or how those allocations will change if the proposal is adopted.
For example, APHIS has set a goal of releasing biocontrol agents in every county with a known EAB infestation where the agent populations can be sustained. The proposal states that, by the end of the 2017 field season, parasitoids had been released in 27 of 32 states and 2 of 3 provinces in which EAB is present (Duan et al. 2018). APHIS does not explain how the current funding allocation hampers achieving the stated goal.
4) The proposal and accompanying regulatory flexibility analysis provide no information about whether APHIS will expand efforts supporting such other EAB impact minimization strategies as breeding trees resistant to emerald ash borer attack.
Even biocontrol practitioners (e.g., Duan et al. 2018 ) point to the importance of including breeding of resistant trees in the future efforts.
5) The proposal offers only vague promises about continuing federal efforts to minimize the risk that human transport of firewood will facilitate spread of the emerald ash borer or other tree pests.
Unfortunately, the impact of an outreach message depends heavily on having a simple, straightforward, unified message. Absent the EAB quarantine, which provides a nation-wide standard for firewood treatment, the “Don’t Move Firewood” campaign will be confronted by the task of trying to explain diverse messages and policies/rules issued by various states, counties, provinces, and managers of parks and other public lands. Hampered by this welter of messages, even the well-managed DMF campaign will struggle to persuade the public to help curtail spread via this pathway.
APHIS today published a set of “frequently asked questions” that address some of the issues raised in this blog. Go here to read the answers.
The Center for Invasive Species Prevention urges all who care about protecting North America’s native flora from non-native insects and diseases to submit comments on this proposed rule before the deadline on 19 November. This can be done by visiting here http://www.regulations.gov/#!docketDetail;D=APHIS-2017-0056.
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.
SOURCES
Abell, K.J., L.S. Bauer, J.J. Duan, R. Van Driesche. 2014. Long-term monitoring of the introduced emerald ash borer (Coleoptera: Buprestidae) egg parasitoid, Oobius agrili (Hymenoptera: Encyrtidae), in MI, USA and evaluation of a newly developed monitoring Technique. Biological Control 79 (2014) 36–42
Duan, J.J., L.S. Bauer, R.G. van Driesche, and J.R. Gould. 2018. Progress & Challenges of Protecting North American Ash Trees from the emerald ash borer Using Biological Control. Forests 2018, 9, 142; doi:10.3390/f9030142
McPherson, G., N. van Doorn, J. de Goedec. 2016. Structure, function and value of street trees in California, USA. USDA Forest Service, Pacific Southwest Research Station Urban Forestry and Urban Greening 17 2016 (104-115)
Nowak, D.J., R.E. Hoehn III, D.E. Crane, A.R. Bodine. Assessing Urban Forest Effects and Values of the Great Plains: Kansas, Nebraska, North Dakota, South Dakota. USDA Forest Service Northern Research Station Resource Bulletin NRS-71
Nowak, D.J., R.E. Hoehn III, D.E. Crane, L. Weller, A. Davila. Assessing Urban Forest Effects and Values: Los Angeles’ Urban Forest. USDA Forest Service Northern Research Station Resource Bulletin NRS-47
Portland Parks and Recreation Street Tree Inventory Findings 2015. www.portlandoregon.gov/parks/treeinventory
Showalter, D.N., K.F. Raffa, R.A. Sniezko, D.A. Herms, A.M. Liebhold, J.A. Smith, P. Bonello. 2018. Strategic Development of Tree Resistance Against Forest Pathogen and Insect Invasions in Defense-Free Space. Frontiers in Ecology & Evolution
Ailanthus altissima
