The United Nations has designated 2020 as the International Year of Plant Health. I welcome the possibility of heightened awareness – although it could result in promises that are more optimistic than facts warrant.
APHIS
and probably other national and international phytosanitary bodies have planned
events to draw attention to the importance protecting of plant health. For
example, the APHIS website lists numerous meetings, some of which are special
events, e.g., Safeguarding 2020: North American
Safeguarding and Safe Trade Conference in Washington, DC, in August.Another event is a continuation
of the Entomological Society of America’s Grand
Challenges event, “Pre-border Prevention: A New Conversation on Invasive
Pest Pathways Through Trade” – which will take place in Orlando in November.
I
repeat that we should support the international phytosanitary community’s
efforts to raise political leaders’ awareness of the importance of preventing
phytosanitary disasters.
However,
at the same time, the international system that, for more than two decades, has
governed trade, with all its associated phytosanitary risks and regulations, is
falling apart.
The World Trade Organization – which is the basis for international trade rules – is under unprecedented threat. United States has blocked nomination of individuals to the World Trade Organization’s Dispute Panel. As of December 10, 2019 the Panel no longer has a quorum. As a result, experts expect countries to revert to the pre-WTO practice of bullying trade “partners” with whom they have a quarrel. They will probably erect tariffs and other barriers in order to force other parties to concede. Phytosanitary requirements might again be governed by individual countries’ bilateral agreements, leading to confusion and perhaps a “race to the bottom” in the name of facilitating trade.
Collapse of the WTO rules alarms me – despite my having criticized WTO restrictions on strong national phytosanitary measures over the past 25 years. (The restrictions were imposed by the WTO’s Agreement on the Application of Sanitary and Phytosanitary Measures – the SPS Agreement). For more details, see Fading Forests II. All-out country vs. country trade battles seldom put a priority on preventing the movement of pests. At least under WTO SPS, there has been a process for addressing pest problems.
Most phytosanitary issues – including development of international standards – are addressed under the International Plant Protection Convention. The IPPC is a separate organization from the WTO, so it might continue to function with fewer disruptions. Still, much of its clout comes from its recognition by the WTO SPS as the standard-setting body for plant health matters.
Rome – home of the IPPC
Of course, there are benefits associated with individual countries’ acting independently. Might the current collapse of trade rules allow the U.S. to adopt more stringent regulations governing introduction pathways of concern to us — for example, wood packaging? Can we hope that an administration focused on “America First” take aggressive phytosanitary actions to protect our agriculture and environment?
Unfortunately,
I see no indications that the U.S. Department of Agriculture – much less other
agencies – might seize this opportunity.
The United Kingdom has an even greater opportunity to act independently, since it is “Brexiting” the European Union in January 2020. In theory, the UK is now free to adopt its own phytosanitary measures. A House of Lords committee held extensive hearings to explore options in 2018.
Clive Brasier
While eminent plant pathologist Clive Brasier and others urged the UK to adopt more stringent rules based on a precautionary approach – for example, by banning imports of semi-mature trees with large root balls – the committee noted that the British government has often said that it wants to maintain “seamless” trade with the EU. It therefore seems unlikely that the UK will seize this opportunity to erect more effective phytosanitary barriers to prevent pest introductions to the islands.
Meantime, the European Union is making some mildly encouraging changes. Europe (including the UK) has the highest number of introduced tree-killing non-native pathogens of any continent – five times more than North America (Ghelardini 2017). Europe has a much more leaky phytosanitary system for plant imports than does the United States. See also Jung et al. (2015), Roy et al. (2014), the Montesclaros Declaration.
participants at the Montesclaros negotiation
In response to growing awareness of the plant pest threat, EU officials have gone through a multi-year process to strengthen phytosanitary rules governing movement of plants for planting (living plants, such as nursery stock). The process was described in Klapwijk et al. (2016) and discussed in my blog in October 2016. The new rules took effect in December 2019. The new European Commission regulation simplifies and harmonizes the “plant passport” system, under which plants are moved among EU member states. Plant imports that pose the greatest risk – called “priority pests” – are subject to enhanced measures concerning surveys, action plans for their eradication, contingency plans and simulation exercises. Plants for planting and plant products being imported into the EU will be subject to varying levels of restrictions, including prohibition of importation of those posing the highest risk. Less risky plants must be accompanied by a phytosanitary certificate issued by the phytosanitary agency of the exporting country (House of Lords report). The new system no longer depends on a list of harmful plant pests, but instead “sets out the conceptual nature of quarantine pests” and empowers the Commission to adopt measures to control certain pests (Klapwijk et al. (2016)).
Three years ago, Klapwijk et al. (2016) praised the new approach as a significant step forward. However, they note that the new rules still don’t provide for precautionary assessments of high-risk commodities. Nor do they actually restrict import of the highest-risk commodities, such as imports of large plants or plants in soil (my emphasis). Such restrictions still must be enacted separately. Organisms whose pest status is unknown will continue to be allowed into the EU. (See discussions of the impact of failing to curtail imports of “unknown unknowns” by Brasier (2008) and in Fading Forests II.
(While the U.S. also does not address organisms with unknown pest potential, it is much more stringent regarding sizes of plants, presence of soil or other growing media, and other issues. Furthermore, it has the NAPPRA process, which facilitates a more rapid response to emerging pest threats.)
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
Brasier
CM. 2008. The biosecurity threat to the UK and global environment from
international trade in plants. Plant Pathology 57: 792–808.
Ghelardini,
L., Luchi, N., Pecori, F., Pepori, A.L., Danti, R., Della Rocca, G., Capretti,
P., Tsopelas, P. , Santini, A. 2017.
Ecology of invasive forest pathogens. Biological Invasions. June 2017
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;
Klapwijk, M., Hopkins, A.J.M., Eriksson, L. Pettersson,
M., Schroeder, M., Lindelo¨w, A., Ro¨nnberg, J. Keskitalo, E.C.H., Kenis, M. 2016. Reducing the risk of invasive
forest pests and pathogens: Combining legislation, targeted management and
public awareness. Ambio 2016, 45(Suppl. 2):S223–S234 DOI 10.1007/s13280-015-0748-3
APHIS proposes to place numerous plant taxa on its list of plants for planting whose
importation is “not authorized pending pest risk analysis” (NAPPRA). Unfortunately, the proposal comes too late for some
pests; doesn’t apply to at least one significant pathway of entry; excludes some
highly damaging newly detected pathogens; and too often applies only to
agricultural pests. Nevertheless, the proposal is worth supporting – while
mentioning those caveats.
APHIS is accepting comments on the data sheets justifying the proposed listings until 24 January. The Data sheets can be obtained here. We encourage you to comment.
APHIS’
Regulatory Framework
Under
APHIS’ regulations in ‘‘Subpart— P4P’’ (7 CFR 319.37 through 319.37–14 …),
APHIS prohibits or restricts the importation of “plants for planting” – living plants,
plant parts, seeds, and plant cuttings – to prevent the introduction of “quarantine
pests” into the US. A “quarantine pest” is defined in § 319.37–1 as a plant
pest or noxious weed that is of potential economic importance to the United States
and not yet present in the country, or is present but not widely distributed
and is being officially controlled.
§
319.37–2a authorizes APHIS to identify those plant taxa whose importation is
not authorized pending pest risk analysis (NAPPRA) in order to prevent their introduction
into the United States. If the plant taxon has been determined to be a probable
invasive species, its importation is restricted from all countries and regions.
If the taxon has been determined to be a host of a plant pest, the list
includes (1) names of affected taxa, (2) the foreign places from which these
taxa’s importation is not authorized, and (3) the quarantine pests of concern.
APHIS finalized a rule giving itself the authority to place plant taxa in the NAPPRA program in 2011; it has previously used this process twice to restrict imports of plant taxa – most recently in 2017.
Plant Taxa that Host a Damaging Pest
or Pathogen
The proposed restrictions would apply to two plant families —
Myrtaceae taxa (when destined to Hawai`i), and the subfamily Bambusoideae
(bamboo); plus 43 other taxa that are likely to transport damaging insects,
pathogens, or viruses.
ohia in bloom; National Park Service photo
1)
All plants in the family Myrtaceae that are destined for Hawai`i.
The proposed restriction is intended to counter the risk that additional strains of the `ohi`a rust pathogen Austropuccinia psidii might be introduced and prove more damaging to native Hawaiian vegetation than the strain already present on the islands. (See description of `ohi`a rust here.
`Ohi`a
rust was detected in Hawai`i in 2005. Detection was followed by scientific
studies to determine whether different strains exist and, if so, whether they
posed a threat to Hawaiian vegetation. Under the circumstances, the proposed
action is disturbingly tardy.
Worse,
the pathogen was probably introduced to Hawai`i on imports of flower and
foliage cuttings, rather than entire plants or propagules. Unfortunately, the
section of APHIS’ regulations that governs imports of plants that can be grown
(“plants for planting”) does not apply to imports of cuttings (including
flowers). In the Federal Register notice, APHIS says it will issue a separate
proposal to tighten regulations on imports of cuttings and flowers. I hope they
move expeditiously on this rulemaking –
which will be more cumbersome in even the best case because it requires
a full rulemaking, not the expedited notice and comment process allowed under
the NAPPRA program.
It is disturbing that the proposal does not include the two Ceratocystis species that are killing millions of `ohi`a trees in Hawai`i link to DMF writeup. It is true that these were identified relatively recently – in 2017. However, other plant taxa proposed for inclusion in the NAPPRA category were also detected or determined to be the cause of a disease as recently as 2017.
ohia trees killed by Ceratocystis; Island of Hawaii; photo by J.B. Friday, University of Hawaii
2) APHIS proposes to include another
pest that might attack a native Hawaiian plant, Phyllanthus distichus. Another species in the genus, P. saffordii is endemic to Guam; it is
listed as endangered under the federal Endangered Species Act. Other Asian
gooseberries in the Phyllanthus genus
are grown in backyards in Hawai`i and other semitropical areas and there is
some interest in expanding commercial uses.
3)
APHIS proposes to include several plant taxa important in tropical agriculture
because of the threat that imports of those plants will transport diseases or
pests. These include two pathogens that threaten production of macadamia nuts (Neopestalotiopsis macadamiae and Pestalotiopsis macadamiae); and pests of
breadfruit, lychee, and durian.
4)
Some of the plant taxa that APHIS hopes to protect from new pests or pathogens
by placing hosts in the NAPPRA category are invasive. These include – in
Hawai`i – Syzygium jambos (rose
apple). It is named as a host of two
pests targetted by the proposed action – the `ohi`a rust pathogen Austropuccinia psidii and armored scale
insect Myrtaspis syzygii.
Euonymus bungeanus (winterberry euonymus) is in the same genus as
several plant species invasive across the continent. APHIS proposes to restrict its importation in
order to prevent introduction of the Euonymus yellow mottle associated virus
(EuYMaV), which has only that plant species as a known host.
5)
APHIS also proposes to add to the NAPPRA category several plant taxa that could
transport the Elm mottle virus (EMoV) because of the threat the virus poses to
several European elm species – and presumably also to North American elms. The
virus also attacks hydrangea and lilac.
In
several cases, some of the primary hosts of the target pest or pathogen are already
in NAPPRA for other reasons from some origins. Nearly all the woody hosts are
already required to undergo post-entry quarantine – which presumably APHIS now
considers to provide inadequate protection.
6) Also proposed are diseases or pests
that threaten grapevines and tomatoes.
Several of the proposed taxa are already
present in the US (including `ohi`a rust). Other proposed listings appear to be
precautionary actions to protect plant taxa that USDA expects to be
increasingly important economically in the future.
Plant
Taxa Proposed Because They Appear Likely to be Invasive
APHIS has proposed 26 plant taxa for inclusion in the NAPPRA category because they might themselves be invasive. Of greatest ecological concern are two taxa of mangroves which had been introduced by early 20th century plant explorer David Fairchild and have since been detected to be spreading in South Florida. These are Bruguiera gymnorhiza and Lumnitzera racemose. Also of concern is a vine that grows in Asian and Indian Ocean mangrove forests, Derris trifoliate.
Bruguiera gymnorhiza; Wikimedia Commons
Several proposed species are aquatic
plants that can form dense mats.
Other taxa proposed appear to possibly
threaten pastures or other agricultural uses.
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.
P. ramorum-infected rhododendron plants Indiana Department of Natural Resources
As you may remember, in June and July I blogged about a troubling outbreak of sudden oak death pathogen Phytophtora ramorum in the nursery trade. The discovery was made by Indiana authorities, who carefully inspected plants being sold in the state. They discovered that rhododendron plants imported from an Oklahoma wholesaler included infected plants.
By the end of May, Indiana state inspectors had destroyed more than 1,500 rhododendrons and prohibited sale of another 1,500 plants pending determination of their health. [source: Indianapolis Star 29 May, 2019] Over the next months, APHIS determined that more than 50 rhododendron plants found in Indiana nurseries had been infected [California Oak Mortality Task Force Newsletter August 2019 ].
In the spring and summer, APHIS and state authorities alerted 28 states that they might have received plants from the suspect sources – the suppliers of the Oklahoma wholesaler — one nursery in Washington State and two nurseries from Canada. In the end, APHIS determined that plants exposed to the pathogen had been sent to 18 states – Alabama, Arkansas, Iowa, Illinois, Indiana, Kansas, Kentucky, Michigan, Missouri, Nebraska, North Carolina, Ohio, Oklahoma, Pennsylvania, Tennessee, Texas, Virginia, and West Virginia. As of late July, P. ramorum-positive nursery stock had been detected in nurseries in seven of these (Iowa, Illinois. Indiana, Kansas, Missouri, Nebraska, Oklahoma) plus Washington [California Oak Mortality Task Force Newsletter August 2019].
As I pointed out in the earlier blog, this is just the latest of several occasions since 2004 in which infected plants have been widely distributed by the nursery trade, despite federal and state regulations. Also, at the time of this outbreak, APHIS had just formalized several steps relaxing the regulations that had been implemented through Federal Orders adopted in recent years. (See the earlier blog for details.)
APHIS actions
I wonder at APHIS’ delay in explaining to stakeholders the situation– and what it is doing about it! APHIS provided minimal information to me – by email rather than a public announcement; this email came a month after Indiana announced detection of the pathogen to the public (as reported in my blog). APHIS issued an official notice even later, in mid-July [California Oak Mortality Task Force (COMTF) Newsletter August 2019]. Neither notice was timely, given the serious risks to both nursery and naturally growing plants from the pathogen.
It
is now November and principal questions have not yet been answered. How did the
inspection systems in Washington and British Columbia fail to detect the
outbreaks before the plants were shipped? This lapse is especially worrisome
because APHIS requires testing of soil and standing water, not just visual
inspection of plants. Furthermore, rhododendrons are well known to be
vulnerable to the pathogen and therefore are a specified focus of detection
efforts!
The October COMTF newsletter includes a report by the Washington State Department of Agriculture that a nursery found positive in May will carry out a Critical Control Points (CCP) assessment. An “extensive fall certification survey” will also be conducted. Presumably, these efforts are aimed at determining how the outbreak occurred.
The Canadian Food Inspection Service (CFIA) described – briefly – its nationwide survey program. CFIA reported that one nursery was determined to be P. ramorum-positive in 2018, three in 2019. CFIA says that trace-forwards and trace-backs demonstrate that no Canadian nursery shipped infected plants to the U.S. in 2018 or 2019. So, apparently, none of the infected plants came from the Canadian nurseries.
I hope that Washington State and APHIS will soon determine the probable causes of the outbreak. APHIS should then promptly inform all stakeholders and engage them in developing improved programs and policies to minimize the likelihood that similar problems will occur again.
Phytosanitary officials from the states are apparently also seeking additional information from APHIS about what went wrong and how the agency plans to fix the problems. See the resolution adopted by the National Plant Board here
California
Action
A much more positive development is that the California Department of Food and Agriculture (CDFA) has introduced a Voluntary P. ramorum Pre-Quarantine Program. This is a voluntary inspection program specifically for nurseries in California counties that are not currently regulated for the pathogen – but that might be put under regulation in the future. Inspections and sampling will be administered by county regulatory officials and samples will be processed by the CDFA Plant Pest Diagnostics Center. If P. ramorum is detected at a participating nursery, the PQP nursery may become a federally regulated establishment.
Broader Implications
As I pointed out in Fading Forests III, APHIS and the states have struggled to prevent spread of tree-killing pests once they have established in the country. Even regulated pests – such as Phytophthora ramorum and the emerald ash borer — have escaped the regulations. APHIS and/or the states have chosen not to engage on other pests, such as redbay ambrosia beetle and laurel wilt disease and the polyphagous and Kuroshio shot hole borers and associated Fusarium fungus. In other cases, some states have acted – and asked APHIS to not get involved – e.g., thousand cankers disease of walnut. This situation heightens the risk to our urban, rural, and wildland forests. Americans need a hard-nosed discussion of how we can improve coordinated efforts to prevent pests’ spread.
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 more than a decade, most countries in the world have required that crates, pallets, spools, and dunnage made from wood be treated in accordance with the requirements of the International Standard for Phytosanitary Protection (ISPM)#15 that
this treatment be certified by applying an approved stamp to the wood. The goal
of the program is to “reduce significantly the risk of introduction and spread
of most quarantine pests that may be associated with that material.”
However,
experience and studies in both the United States and Europe demonstrate that the
ISPM#15 stamp is not a reliable indicator of whether the wood packaging is
pest-free.
1) In the United States, over a period of nine years – Fiscal Years 2010 through 2018 – U.S. Customs and Border Protection (CBP) detected 9,500 consignments harboring a pest in a regulated taxonomic group. Of the shipments found with infested wood packaging, 97% bore the ISPM#15 mark (See Harriger reference at the end of the blog). The wood packaging was from nearly all trading countries. 2) In the past two years, CBP inspectors have repeatedly found pests in dunnage bearing the ISPM#15 mark – as reported by U.S. importers of “break bulk” cargo into Houston. While most of the criticism of non-compliant wood packaging refers to countries in Asia and the Americas, at least one of the Houston importers obtains its dunnage in Europe.
3)
In Europe, a two-year intensive survey of wood packaging associated with
shipments of stone from China to the 28 European Union countries over the period
2013-2016 again found that 97.5% of
consignments found to harbor pests bore the ISPM#15 mark (Eyre et al. 2018). The scientists concluded
that the ISPM-15 mark was of little
value in predicting whether harmful organisms were present. (Eyre et al. 2018, p. 712)
As I have noted in previous blogs and policy briefs, the only in-depth study of the “approach rate” of pests in wood packaging, based on data which is now a decade old, found that 0.1% of incoming wood packaging transported a regulated pest (Haack et al. 2014). Given current trade volumes, as many as 17,650 containers per year (or 48 per day) transporting tree-killing insects might be entering the U.S. (My calculation of this estimate is explained in the blog on “risks of introduction” here.)
The
Haack study excluded imports from Mexico, Canada, and China. The first and
third countries have records of poor compliance with ISPM#15 requirements, so
the “approach rate” for all incoming shipments might well have been higher.
The
study of European imports focused on shipments of stone from China – which were
deliberately chosen to represent types of imports presenting a high risk of
transporting pests. Across Europe, over the four-year period, quarantine pests
were detected in 0.9% of the consignments – somewhat higher than the U.S.
number, as could be expected. However, there were large variations among participating
countries’ findings. Austria and France found 6.95% of consignments inspected
were infested, while half of European Union countries found none!
These differences demonstrate the importance of thorough inspections.
The data also indicate
that the problem is not decreasing. Austria detected pests in nearly one-fifth
(19.6%) of inspected shipments in 2016 – the final year of the study! However,
during that same year, only 1.5% of wood packaging lacked the ISPM#15 mark.
So How Should the
International Phytosanitary Community React to This Failure?
Data
cited in numerous studies indicate that ISPM#15 has probably succeeded in
reducing the presence of pests in wood packaging. This progress is good – but
insufficient. Our forests need further reductions.
In the meantime, however, the international standard has demonstrably failed to provide a secure method to evaluate the pest risk associated with wood packaging accompanying any particular shipment. The presence of the stamp on pieces of wood packaging does not reliably show that the wood is pest-free. Officials need to determine why. Is it fraud? That would mean deliberately placing the stamp on wood that had not been treated, which U.S. CBP staffers think is occurring (Harriger). The European Union audit team that visited China also thought they detected instances of fraud. They concluded that “the current system of official controls in China does not adequately ensure that SWPM which forms part of consignments of goods exported to the EU is marked and treated according to ISPM No. 15” (Eyre et al. 2018, p. 713). On the other hand, the US importers in Houston say they are pressing their European suppliers to provide pest-free dunnage.
What
more could we ask them to do to ensure that they are not receiving fraudulently
marked materials?
Perhaps
the problem has a different cause. Are the treatments themselves are less
effective than expected? One APHIS study found that twice as many larvae reared
from wood treated by methyl bromide fumigation survived to adulthood than
larvae reared from heat-treated wood; the reason is unclear (Nadel et al. 2016). Unfortunately, it is
apparently impractical to determine whether wood was heat treated by looking
for changes in the chemical profile of the wood (Eyre et al. 2018).
Nor
can we expect inspection of 100% of all risky consignments or detection of 100%
of quarantine pests in those consignments that are inspected. Therefore, the
European study authors concluded that inspection is best considered as a means
of gathering evidence of risk and a deterrent rather than a means of completely
preventing pest movement (Eyre et al.
2018).
The
European study authors called for review of ISPM#15 as a control system and to
investigate compliance at the source (Eyre et
al. 2018 p. 714).
What is APHIS
doing?
As I have noted previously – here and here – while U.S. CBP adopted a policy in 2017 under which it can penalize importers for each consignment not in compliance with ISPM#15, APHIS has not followed Custom’s lead on this. Instead, APHIS will apply a penalty only when an importer has accrued five violations over the period of a year. (The two agencies are acting under separate legal authorities.) This is yet another example of APHIS taking a less protective stance – as I described in earlier blogs.
Since
Customs is now applying the letter of the law, the most useful step would
probably be for APHIS (and the USDA Foreign Agriculture Service) to ramp up
efforts to assist U.S. importers which are trying to comply. The importers are
begging USDA to provide better information to them about foreign suppliers of wood
packaging and dunnage. Which have good vs.
poor records? USDA could also help importers trying to complain about specific
shipments to the exporting countries’ National Plant Protection Organizations
(NPPOs; departments of agriculture). In
addition, APHIS could augment its pressure on foreign NPPOs and the
International Plant Protection Convention more generally to ascertain the
reasons ISPM#15 is failing and to fix the problems.
APHIS has not been idle. The North American Plant Protection Organization (including Canada and Mexico) has sponsored two workshops intended to educate NPPOs and exporters in Asia and the Americas about the standard’s requirements. APHIS is planning to address wood packaging in an international symposium organized under the auspices of the International Year of Plant Health in July 2020 – I will provide details when they become available.
APHIS is collaborating with the Entomological Society of America to host a workshop on wood packaging at the ESA annual meeting in November 2020 – I will provide details when they become available. The Continental Dialogue on Non-Native Forest Insects and Diseases plans to link its annual 2020 meeting to this workshop.
More immediately, the Continental Dialogue on Non-Native Forest Insects and Diseases will have presentations on the wood packaging issue at its annual meeting in just 11 days! in Cleveland
In preparation for the 2020 meetings, APHIS should fund more studies and audits of wood packaging to document the current efficacy of the standard (that is, the pest approach rate); remember, Haack’s study relied on data which are now a decade old. Not only has time passed … Both the standard and U.S. enforcement policies have changed since 2009.
Significance of the
Wood Packaging Problems
The
apparent failure of the ISPM#15 standard to provide a reliable means to certify
treatment raises obvious issues regarding the risk of pest introductions.
However, the implications are much broader.
The premise of the international phytosanitary system – the Agreement on the Application of Sanitary and Phytosanitary Standards (SPS Agreement) and International Plant Protection Convention (IPPC) – is that importing countries should rely on exporting countries to take the actions necessary to meet the importing countries’ plant health goals. The ISPM#15 experience casts doubt on this premise. The exporters are not reliably ensuring the cleanliness of their wood packaging. Worse, wood packaging is easier to treat than fruits, vegetables, and living plants (plants for planting). The latter commodities are much more easily damaged or killed by treatments than are boards or even logs – which are, after all, already dead! (A longer discussion of the SPS Agreement and IPPC is found in Chapter III of Fading Forests II, available here.
I
hope that the international phytosanitary community will take advantage of the
heightened attention and effort associated with the International Year of Plant
Health in 2020 to re-examine all aspects of the current global phytosanitary system.
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
Eyre,
D., R. Macarthur, R.A. Haack, Y. Lu, and H. Krehan. 2018. Variation in
Inspection Efficacy by Member States of SWPM Entering EU. Journal of Economic
Entomology, 111(2), 2018, 707–715)
Nadel,
N., S. Myers, J. Molongoski, Y. Wu, S. Linafelter, A. Ray S. Krishnankutty, and
A. Taylor. 2016. Identificantion of Port Interceptions in Wood Packaging
Material: Cumulative Progress Report, April 2012 – August 2016
redbay in Georgia killed by laurel wilt photo by Scott Cameron
In August I posted a blog summarizing information on pest introductions and impacts gleaned over my nearly 30 years of engagement. Already, I need to post an update, with an alarming estimate of introduced pests’ impacts across the continent.
Fei
et al. 2019 (see the full citation is
at the end of this blog) estimate that the
15 most damaging introduced species threaten 41.1% of the total live forest
biomass in the 48 conterminous states.
In
fact, this might be an underestimate
of the pests’ impacts on biomass loss. Fei et
al. (2019) note several limitations in their data that might result in such
an underestimate. These include:
1)
Mortality rates – and impacts – may increase over several decades following the
initial invasion.
2)
For pests already established throughout nearly all their potential ranges,
pest-induced biomass loss could be substantially underestimated because most of
their hosts died long ago, before the FIA data began to be collected. Consequently,
the actual loss of these tree species from the forest is much greater than has
been measured by the study’s methods.
3)
Mortality rates vary among species and regions, which might introduce errors.
They cite European gypsy moth, in which relatively small areas of heightened
mortality due to repeated defoliations are swamped by lower mortality rates
across the chosen measurement area.
4)
They considered only tree mortality, not crown or root dieback or reductions in
tree growth.
5)
They did not estimate carbon release to the forest floor as a result of
defoliation.
6)
Pest-related mortality rates may be underestimated due to salvage – although
the authors did not observe evidence of substantial salvage efforts for most of
these pests.
7)
The data did not include losses from urban tree mortality.
Fei
et al. estimate that more than 450 pests
are established in the 48 conterminous states. This study excluded pests
attacking palms; trees on U.S. Pacific and Caribbean islands; and pests native
to portions of North America that are causing severe damage in naïve hosts – e.g., goldspotted oak borer. I did
include the latter groups in my slightly larger estimate laid out in my August
blog.
Fei
et al. base their analysis on 83 of
the introduced pest species considered to cause substantial effects on tree
health and productivity and sometimes extensive tree mortality. (In my August
blog, I described findings by another study by Guo et al (2019) that counted 91 species in that category.)
Fei et al. build on studies by a group of USDA Forest Service (USFS) scientists that I described in an earlier blog.
This team found that, nation-wide, non-native forest pests are causing an approximate 5% increase in total annual mortality by tree volume. They based their studies on analysis of 92,978 long-term plots maintained by the USDA Forest Inventory and Analysis program.
As
noted above, the article cannot capture the full range of mortality in species
affected by pests introduced decades ago. Chestnut blight, white pine blister
rust, Port-Orford-Cedar root disease, beech bark disease, butternut canker,
dogwood anthracnose, and European gypsy moths had all killed millions of trees
before the USFS forest inventory plots were established. Fei et al. do form a solid basis for measuring some of the current
impacts and projecting future ones.
The
focus of the new article is on the amount of carbon being transferred from live
biomass to dead organic matter as a result of the increased mortality caused by
the 15 species with the highest impacts. This is arguably a more quantifiable
measure of pests’ impacts than others’ approaches. Here, I focus more narrowly on the
documentation of exacerbated mortality as measured by the loss of biomass. Added
together, these 15 species have caused an additional (i.e., above background levels) tree mortality rate of 5.53 TgC per
year [defined as terragrams of carbon]. This
estimate of annual conversion of live biomass to dead wood is similar in
magnitude to that attributed to fire (5.4 to 14.2 TgC per year) (Fei et al. 2019). Yet the fire threat gets
much more attention – for both prevention and management.
It
is important to remember that conversion of living biomass to dead wood does
not result in an immediate release of carbon to the atmosphere. Atmospheric releases
take place through decomposition which is both gradual and takes place at
varying rates. Some of the carbon will remain in the soil. And, over time, some
of the carbon storage capacity will be restored by compensatory growth in
unaffected trees and the recruitment of new regeneration – although this faster
growth is delayed by as much as two or more decades after pest invasions begin
(Fei et al. 2019).
American elm being killed by “Dutch” elm disease photo by Cheryl Kaiser, University of Kentucky; bugwood.org
The 15 species of introduced pests used in this analysis
are laurel
wilt disease, chestnut blight, butternut canker, dogwood anthracnose, emerald
ash borer (EAB), Dutch elm disease, red pine scale, beech bark disease, hemlock
woolly adelgid, balsam woolly adelgid, European gypsy moth, white pine blister
rust, green spruce aphid, sudden oak death, and Port-Orford cedar root disease.
Of these, the highest elevation in biomass loss – as measured by FIA plot data
– was caused by EAB, Dutch elm disease, beech bark disease, and hemlock woolly
adelgid. We know that elms and beech, at least, began dying decades before the
FIA data began to be collected. So the reported mortality rates are an
underestimate. This is especially true because beech mortality is highest in
the first decade after invasion by beech bark disease.
Annual levels of biomass loss are virtually certain to increase. First, pests will spread to new host ranges and infestations in already-invaded ranges will intensify. As a result, substantial amounts of the hosts’ biomass are at risk of exacerbated mortality. As I noted at the top of the blog, the total amount of host biomass at risk from these 15 species is estimated to be 5,197 TgC – or 41.1% of the total live forest biomass in the 48 conterminous states. Further exacerbating future losses is the likelihood that additional pests will be introduced. I would add that pests not included in this analysis – e.g., polyphagous and Kuroshio shot hole borers and possibly the spotted lanternfly – are also likely to contribute to losses of live forest biomass.
Fei
et al. (2019) did not attempt to
determine the economic value of this biomass loss or to address other types of
losses to ecosystem services.
Remember that a separate set of studies reported by Potter et al. (2019) (the CAPTURE project) also relied on data from the FIA plots to evaluate the impact of introduced pests. These studies focused on identifying the host species at greatest risk rather than highest-impact pests or biomass loss. I find it reassuring that the Fei and Potter studies – using different approaches – resulted in very similar species rankings. See my discussion of the Potter studies here.
Together, the teams led by Potter and Fei set clear priorities for addressing the threats from non-native pests. What we need now is action! See my recommendations in my recent “solutions” blog.
U.S. Capitol – inform your representatives that you want action to protect trees!
SOURCES
Fei,
S., R.S. Morin, C.M. Oswalt, and A.M. 2019. Biomass losses resulting from
insect and disease invasions in United States forests
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)
Fiscal
Year 2020 began on 1 October. Congress has not yet passed funding bills
(appropriations) for the full year. Agencies are operating now on a short-term
continuing resolution which expires on November 21st. Meanwhile,
representatives of the House and Senate will meet to reconcile the differences
between the two bodies’ appropriations bills in hope that a year-long bill can
be finalized by that time.
(Disagreement
between President Trump and the Congress about funding for the border wall
might prevent adoption of full-year appropriations bills and lead to another
government shutdown.)
I
report here the differences between House and Senate bills funding the USDA
APHIS and Forest Service programs that are vital to addressing non-native
forest pests.
APHIS
Over
the years, I have complained that inadequate funding is a major cause of
shortfalls in APHIS’ efforts to detect new invasions by tree-killing pests and to
respond to those invasions in effective ways.
While
funding levels are still too low, at least Congress is holding funding steady
for APHIS for Fiscal Year 2020 (which began three weeks ago, on October 1st).
Both House and Senate bills maintain funding for two crucial programs at the
FY19 levels:
“tree
and wood pests” program – $60 million (this matches the FY19 level; it is $4
million above the funding provided in previous years); and
“Pest
Detection” – $27.4 million.
The
House provided slightly higher funding than the Senate for two other programs:
“specialty
crops” (including sudden oak death) – $186.5 million in the House bill, $186
million in the Senate bill; and
“methods
development” – $21.686 million in the House bill, $20.686 million in the Senate
bill.
In the report accompanying its bill, the House called for two additional funding options to address emergencies. First, it set up a contingency fund of $470,000 to control outbreaks of insects, plant diseases, animal diseases and pest animals and birds to meet emergency conditions. Second, the report repeated language from past reports that authorizes the Secretary to take “such sums as may be deemed necessary” from other USDA programs in order to counter pest emergencies threatening any segment of U.S. agricultural production.
The Senate report addressed several high-profile tree pests. It called for complete eradication of the Asian longhorned beetle; mandated that APHIS report on its efforts to eradicate ALB and spotted lanternfly and to minimize spread of the polyphagous and Kuroshio shot hole borers; and to assist states that have recently detected the emerald ash borer. (This language is helpful, but it falls short of what I previously advocated – that APHIS continue efforts to prevent EAB spread, especially through movement of firewood.) The Senate report also urged APHIS to maintain FY19 level funding addressing the sudden oak death pathogen, in particular to improve understanding of the two strains of the pathogen present in Oregon’s forests link to blog to inform control and management techniques in wildlands. (Actually, management in wildlands falls largely to the Forest Service, with scientific input from both Agriculture Research Service and – to some extent – the NORS-DUC research nursery managed by APHIS.)
For a lengthier justification of my funding requests, see my earlier blog on APHIS funding
Funding for
Resistance Breeding through NIFA
As I pointed out in my blog in May, the 2018 Farm Bill included an amendment (Section 8708) that establishes a new priority for a grant program managed by the National Institute of Food and Agriculture. The amendment would support restoration to the forest of native tree species that have suffered severe levels of mortality caused by non-native insects, plant pathogens, or other pests. The amendment affects the Competitive Forestry, Natural Resources, and Environmental Grants Program under Section 1232(c)(2) of the Food, Agriculture, Conservation, and Trade Act of 1990 (16 U.S.C. 582A-8, as amended. However, this program has not been funded for more than a decade. In my blog, I asked you to support a $10 million appropriation to NIFA to fund a competitive grant program for such forests restoration.
Neither the House nor the Senate provided funding for
this program.
USFS
The House bill provides $277,155,000 for USFS Research and Development – nearly $20 million more than the Senate bill ($257,640,000). The House report links this increase to the recognition of the increasing risk to urban, rural, and wildland forests from insect and disease outbreaks and invasive plant infestations. The report calls on the Forest Service to develop a research program that addresses several priorities critical to forest health, including preventing the spread of disease and invasive species.
USFS engagement on pest issues with other federal agencies and state, local government, and private land managers is carried out through the Forest Health Management program under the State and Private Forestry division. The Senate bill and report are confusing because they have separated out salaries and other expenses. As a result, I can’t compare its figures to those in previous years or to those from the House. Partly for this reason, I urge you to support the House bill, which is quite clear in appropriating $103,736,000 for Forest Health Management, which is a programmatic increase of $19 million above the FY19 level and $29,919,000 above the budget request. I am encouraged by the House’ report, which encourages the Forest Service to address high priority invasive species, pests, and diseases, including the emerald ash borer and bark beetle infestations.
For longer explanations, see my earlier blog on USFS funding.
These bills show an increasing awareness of forest
pest issues in key funding committees in both the House and Senate. Let’s reinforce this message – and spread it
to the rest of Congress. Please contact your senators and representative and
ask them to support these funding levels.
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.
Faith Campbell receives award for activism from National Association of State Foresters; 2016
For nearly 30 years I have documented bioinvasion threats and gaps, first in three Fading Forests reports (available here), then in five years of blogging. Here I pull together that information and suggest — in most cases reiterate — steps to address these threats and gaps. I list sources of discussion of the underlying issues – other than my reports and blogs – in references at the end of this blog.
My
first premise is: robust federal leadership is crucial:
The Constitution gives primacy to
federal agencies in managing imports and interstate trade.
Only a consistent approach can
protect trees (and other plants) from non-native pests.
Federal agencies have more
resources than state agencies individually or in any likely collective effort
— despite decades of budget and staffing cuts.
My
second premise is: success depends on a continuing, long-term effort founded on
institutional and financial commitments commensurate with the scale of the threat.
This requires stable funding; guidance by research and expert staff; and engagement
by non-governmental players and stakeholders. Unfortunately, as I discuss
below, funding has not been adequate or stable.
My third premise is that programs’ effectiveness needs to be measured, not just effort (see the NECIS document referenced at the end of the blog).
SPECIFICS
Preventing
new introductions continues to be the most effective action. Mitigating options
decrease and damages increase once a non-native pest has entered the country –
much less become established (see Lovett et
al. 2016 and Roy et al. 2014). I
recognize that preventing new introductions poses an extremely difficult
challenge given the volume and speed of international trade and the strong
economic forces supporting free trade. These challenges have been exacerbated over
several decades by the political zeitgeist – the anti-regulatory ideology, the emphasis
on “collaborating” with “clients” rather than imposing requirements through
regulations. Although the current “America First” policy might reduce import
volumes and therefore reduce the invasive species threat to some extent, the
anti-regulatory stance has only strengthened.
containers at the Port of Long Beach, California
Decades of cutting key agencies’ budgets and personnel are another factor. However, the damage to America’s natural systems is so great that we must try harder to find more effective strategies (See the Fading Forest reports; my previous blogs; Lovett et al. 2016; and APHIS annual reports – e.g., the 2019 report here)
Prevention
Despite adoption and implementation of new international and national regulations to stem pest introductions, introductions continue – although probably at a lower level than would otherwise be the case. Delays in adoption of regulations (documented in Fading Forests II and III and my two recent 30-years-in-review blogs have facilitated damaging introductions and spread.
Solutions
Stakeholders press USDA
leadership to initiate rules intended to strengthen phytosanitary protection and
expedite their completion
APHIS promote and facilitate
analysis of current programs and policies by non-agency experts to ensure the
agency is applying most effective strategies (Lovett et al. 2016).
Adoption
of insufficiently protective regulations (documented in FFII, FFIII, two
30-years-in-review blogs) – adopted in part because APHIS is trying to
“balance” trade facilitation and phytosanitary protection – has further
contributed to damaging pests’ introduction and spread.
Solutions:
Boost
priority of preventing pest introductions by amending the Congressional finding
in the Plant Protection Act [7 USC 7701(3)] as follows
Existing language: “[I]t is the
responsibility of the Secretary [of Agriculture] to facilitate exports, imports
and interstate commerce in . . . commodities that pose a risk of harboring
plant pests or noxious weeds in ways that
will reduce, to the extent practicable, as determined by the Secretary, the
risk of dissemination of plant pests and noxious weeds .… “
Amend to read as follows: “…. in ways that will reduce prevent, to the greatest extent practicable feasible, as determined by the Secretary, …” [emphasis added]
Adopt several actions to
strengthen phytosanitary protections at the point of origin (Lovett et al. 2016)
Expand
pre-clearance partnerships — as authorized for plants under Q-37 regulations
and ISPM-36
Expand
sentinel tree programs
Promote
voluntary substitution of packaging made from materials other than solid wood.
APHIS
doesn’t use the enforcement powers that it has under Plant Protection Act (see
several of my past blogs)
Solutions:
CBP inspectors search for pests in a pallet; CBP photo
APHIS follow the lead of Customs and Border Protection and begin penalizing importers on the first instance of their wood packaging not being in compliance with ISPM#15 (see blog here).
APHIS prohibit use of wood packaging by countries and importers of categories of imports that – over the 13 years since implementation – have developed a record of frequent violations of ISPM#15.
APHIS use its authority per revised Q-37 regulations to negotiate with countries that export plants to the U.S. to establish “integrated measures” programs aimed at minimizing the risk of associated pests being transported to the U.S.
APHIS use its authority per revised Q-37 to place in the “Not Authorized for Import Pending Pest Risk Assessment (NAPPRA) “limbo” category genera containing North American “woody” plants (see Roy et al. 2014; Lovett et al. 2016).
Spread within the
U.S.
The
United States lacks a coordinated system to prevent pest spread within the
country (see Fading Forests III Chapter 5). Even our strictest methods, like APHIS’s
quarantines regulating interstate movement of goods, have failed to curtail
spread of significant pests. The most obvious example is the emerald ash borer.
The regulations governing movement of the sudden oak death pathogen in the nursery trade have also failed: there have been periodic outbreaks in which the pathogen has been spread to nurseries across the country. Between 2003 and 2011, a total of 464 nurseries located in 27 states tested positive for the pathogen, the majority as a result of shipments traced from infested wholesalers. In 2019, plants exposed to the pathogen were again shipped to 18 states; eight of those states have confirmed that their plant retailers received infected plants (see my blog from summer here).
Another
serious gap is the frequent failure of APHIS and states to adopt official
programs targetting bioinvaders that will be difficult to control because of
biological characteristics or cryptic natures – even when severe impacts are
demonstrated. Recent examples include the laurel wilt disease complex, goldspotted
oak borer, polyphagous and Kuroshio shot hole borers and associated pathogens,
and even the spotted lanternfly (although the last has received significant
funds from APHIS.)
redbay killed by laurel wilt disease, Georgia; photo by Scott Cameron
Solutions:
APHIS apply much more stringent
regulations to interstate movement, based on a heightened priority for
prevention in contrast to facilitating interstate trade. E.g., prohibit nurseries on the West Coast from shipping P. ramorum hosts to states where the pathogen
is not established.
APHIS encourage states to adopt
quarantines and regulations aimed at preventing spread of invasive pests to
regions of the state that are not yet infested. For example, the sudden oak
death pathogen in California and Oregon; the borers in southern California.
APHIS abandon plans to deregulate
emerald ash borer and step up its support for state regulations on firewood.
APHIS stop dumping pests it no
longer wants to regulate onto the states through the “Federally Recognized
State Manage Phytosanitary (FRSMP) program”.
APHIS revise its policies so that
the “special needs exemption” [7 U.S.C. 7756] actually allows states to adopt
more stringent regulations to prevent introduction of APHIS-designated
quarantine pests (see Fading Forests III Chapter 3).
To help fill the gaps, the states are trying to coordinate their regulations in some important areas. The most advanced example is the voluntary Systems Approach to Nursery Certification, or SANC program. APHIS has supported this initiative, including by funding from the Plant Pest and Disease Management and Disaster Program (see below). However, it is a slow process; USDA funds first became available in 2010. The states are trying to coordinate on firewood, but we don’t yet know what the process will be.
Funding shortfalls (See the three Fading Forests
reports, my blogs about appropriations)
Increase APHIS’ access to emergency
funds from the Commodity Credit Corporation by
amending the Plant Protection Act [7 U.S.C. 7772 (a)] to include this
new definition of “emergency”:
the term “emergency” means any
outbreak of a plant pest or noxious weed which directly or indirectly threatens
any segment of the agricultural production of the United States and for which
the then available appropriated funds are determined by the Secretary to be
insufficient to timely achieve the arrest, control, eradication, or prevention
of the spread of such plant pest or noxious weed.
Although APHIS has the most
robust prevention program of any federal agency, its funding is still
inadequate. Stakeholders should lobby the Congress in support of higher annual
appropriations.
The Plant
Pest and Disease Management and Disaster Program (now under Section 7721 of the
Plant Protection Act) has provided at least $77 million for tree-pest
programs (excluding NORS-DUC & sentinel plant programs and other programs)
since FY 2008. Much useful work has been carried out with these funds. However,
these short-term grants cannot substitute for stable, long-term funding. I
reiterate my call for stakeholders to lobby the Congress to provide larger
appropriations to the APHIS Plant Protection program and Forest Service Forest
Health Protection and Research programs.
Long-term Responses
to Bioinvasive Challenge
More stakeholders are advocating raising the priority of – and providing adequate resources to – such long-term solutions as biocontrol and breeding trees resistant to pests and restoring them to our forests. Advocates include the state forestry agencies of the Northeast and Midwest, some non-governmental organizations, some academics, and individual USFS scientists. One effort resulted in inclusion of language in the 2018 Farm Bill (see blog here) – although this approach has apparently run into a dead end. The new emphasis on breeding has so far not been supported by agency or Congressional leaderships.
test planting of an American chestnut bred to be resistant to chestnut blight
Solutions:
USFS convene workshop of the
federal, state, National Academy, academic, and NGO groups promoting resistance
breeding in order to develop consensus on priorities and general structure of program.
Explicitly include evaluation of the
CAPTURE Project’s (see blog here) efforts to
set priorities to guide funding allocations and policies; and proposals for
providing needed supportive infrastructure – facilities, trained staff in
various disciplines. (See my blogs here.)
Report results of meeting to USDA
leadership, Congress, and stakeholders
Then ensure implementation of the
accepted approach by both Research and Development and Forest Health Protection
programs. Include provisions to provide sustainable funding.
These proposed actions still do not address ways to correct the provisions of the international phytosanitary agreements (World Trade Organization and International Plant Protection Convention) that complicate – or preclude – efforts to prevent introduction of pests currently unknown to science. This issue is discussed in Fading Forests II. A current example is beech leaf disease (described here).
Continuing
inadequate engagement by stakeholders
Most
constituencies that Americans expect to protect our forests don’t press
decision-makers to fix the problems I have identified above: inadequate
resources, weak and tardy phytosanitary measures. Some of these stakeholders
are other federal agencies, or state agencies – or their staffs. They face
restrictions on how “political” they can be. But where are the professional and scientific associations,
representatives of the wood products industry, forest landowners, environmental NGOs and their funders, urban
tree advocates Efforts by me, USDA, and others to better engage these groups
have had disappointing results.
As
I have documented, groups of USFS scientists have made several attempts to
document the extent of invasive species threats and impacts and to set
priorities. So far, they have not gained much traction. Another USFS attempt,
Poland et al. in press, will appear
at the end of the year. Will this be more successful?
I
detect growing attention to educating citizen scientists for early detection;
but if there is an inadequate – or no – official response to their efforts
won’t people become discouraged?
SOURCES
Lovett,
G.M., M. Weiss, A.M. Liebhold, T.P. Holmes,
B. Leung, K.F. Lambert, D.A. Orwig, F.T. Campbell, J. Rosenthal, D.G. McCullough,
R. Wildova, M.P. Ayres, C.D. Canham, D.R. Foster, SL. Ladeau, and T. Weldy.
2016. NIS forest insects and pathogens in the US: Impacts and policy options. Ecological
Applications, 26(5), 2016, pp. 1437–1455
National Environmental Coalition on Invasive Species “Tackling the Challenge.”
Poland,
T.M., Patel-Weynand, T., Finch, D., Miniat, C. F., and Lopez, V. (Eds) (2019),
Invasive Species in Forests and Grasslands of the United States: A
Comprehensive Science Synthesis for the United States Forest Sector. Springer Verlag. (in press).
Roy,
B.A., H.M Alexander, J. Davidson, F.T Campbell, J.J Burdon, R. Sniezko, and C.
Brasier. 2014. Increasing forest loss worldwide from P&Ps requires new
trade regulations. Front Ecol Environ 2014; 12(8): 457–465
It
is widely recognized that invasions of non-native species occur as a
consequence of international trade (see Seebens et. al. 2017 – full citations at the end of this blog). This is as
true for non-native forest pests as for any other bioinvader – see Aukema et al. 2010; Liebhold et al. 2012, Lovett et al. 2016. In fact, gross domestic product – as an indicator of levels
of trade — is a better predictor of the number of forest pest invasions in a
given country than the country’s amount of forested land (Roy et al. 2014).
shipping containers at port of Long Beach, California
As I noted in my previous blog, I began studying and writing about the threat to North America’s forests from non-native insects and pathogens in the early 1990s. I reported my analyses of the evolving threat in the three “Fading Forests” reports – coauthored by Scott Schlarbaum – in 1994, 2003, and 2014. These reports are available here.
I document here that both introduction
and spread of pests within the country have continued apace. While significant
efforts have been made to prevent introductions (described briefly under the
“Invasives 101” tab of the CISP website), they have fallen short. As I noted in
Fading Forests III, programs aimed at preventing spread of pests within the
country remain fragmented and often are unsuccessful.
The Challenge: Huge Volumes of goods are moving, providing
opportunities for pests
Since 1990, volumes of imported goods more than quintupled. Within the U.S., a total of 17,978 million tons of goods were transported in 2015; 10,776 million tons of this total by truck. About one-third of this total – 5,800 million tons – was moved farther than 250 miles. These vehicles moved on a public roads network of 4,154,727 miles (US DOT FFA). Consequently, once a pest enters the U.S., it can be moved quickly into every corner of the country.
Introductions
By and large,
establishment of tree-killing pests has occurred at a fairly steady rate of
about 2.5 per year, with “high-impact” insects and pathogens accumulating at
0.43 per year (Aukema et al. 2010). Since
introductions did not rise commensurately with rising import volumes, Lovett et al. (2016) concluded that the
recently adopted policies for preventing introductions referenced above are
having positive effects but are insufficient to reduce the influx of pests in
the face of ever-growing global trade volumes. The study’s authors went on to
say that absent more effective policies, they expect the continued increase in
trade will bring many new establishments of non-native forest pests.
One group of forest
pests did not enter at a steady rate, but rather entered at a higher rate since
1985 – wood-boring insects. Experts concluded that the increase probably
reflected increases in containerized shipping (Lovett et al. 2016). At the global level, the rate of fungal invasions has
also recently been reported to be increasing rapidly (Roy et al. 2014).
Asian longhorned beetle
Geography of trade
patterns also matters. Opening of trade with China (in 1979) offered
opportunities for pests from a new source country which has a similar climate
and biology. Roy et al. describe the importance of phylogenetic
relatedness of pests and of tree hosts in explaining tree species’ vulnerability
to introduced pests. The most vulnerable forests are those made up of species
similar to those growing in the source of the traded goods – i.e., the temperate forests of the
northeastern U.S. – when goods are imported from similar forested areas of
Europe and Asia. Chinese-origin wood-boring pests began to be detected around
1990. This already short interval probably underestimates how quickly pests
began arriving; detection methods were poor in those years, so a pest was often
present for close to a decade before detection.
Between 1980 and 2016, at least 30 non-native species of wood- or bark-boring insects in the Scolytinae / Scolytidae were newly detected in the United States (Haack and Rabaglia 2013; Rabaglia et al. 2019). Over the same period, approximately 20 additional tree pests were introduced to the continental states (Wu et al. 2017; Digirolomo et al. 2019; R. Haack, pers. comm.) plus about seven to America’s Pacific islands. Not all of the new species are highly damaging, but enough are. See my previous blog here.
Many of the tree-killing
pests were probably associated with pathways other than wood packaging. These
include 6 of the 7 Agrilus species, sudden oak death pathogen, three pests of palm trees, the
spotted lanternfly, beech leaf disease; and the pests introduced to America’s
Pacific Islands.
HIGH-RISK
PATHWAYS OF INTRODUCTION
Already
in the 1990’s it was evident that better preventing pest introductions would
depend on shutting down the variety of pathways by which they move around the
world. At that time, attention focused on imports of
logs and nursery stock (nursery stock makes up one component of a broader
category called by phytosanitary agencies “plants for planting”). Both logs and
“plants for planting” had well-established histories of transporting pests and
import volumes were expected to grow. We have since learned that there are many
more pathways!
Plants for Planting
Imports of “plants for planting” (phytosanitary agencies’ term, which encompasses nursery stock, roots, bulbs, seeds, and other plant parts that can be planted) have long been recognized as a dangerous pathway for introduction of forest pests. For example, this risk was the rationale for adopting the 1912 Plant Quarantine Act. Charles Marlatt, Chairman of USDA’s Federal Horticultural Board (see “Then and Now” in Fading Forests III here), wrote about the risk in National Geographic in April 1911 (urging adoption of the 1912 law) and again in August 1921. See also Brasier (2008), Roy et al. (2014), Liebhold et al. (2012), Jung et al. (2016).
Japanese cherry trees being burned because of scale infestation January 28, 1910; Agriculture Research Service
Of the 91 most
damaging non-native forest pest species in the U.S. (Guo et al. 2019), about 62% are thought to have entered North America
with imports of live plants. These include nearly all the sap-feeding insects,
almost 90% of the foliage-feeding insects, and approximately half of the
pathogens introduced during the period 1860-2006 (Liebhold et al. 2012). Specific examples include chestnut blight, white pine
blister rust, Port-Orford-cedar root disease, balsam woolly adelgid, hemlock
woolly adelgid, beech scale, butternut canker, dogwood anthracnose, and sudden
oak death. In more recent years, introductions via this pathway possibly
include ‘ōhi‘a
rust, rapid ‘ōhi‘a death pathogens, and beech leaf disease. The gypsy
moth, while a foliage feeder, was not introduced via imports of live plants.
The
APHIS annual report for 2018 reported that in that year we imported 18,502
shipments containing more than 1.7 billion
plant units (plants, bulbs, in vitro materials, etc.).
Liebhold et al. 2012, relying on 2009 data, found that about 12 percent of incoming plant shipments had symptoms of pests – a rate more than 100 times greater than that for wood packaging. Worse, a high percentage of the pests associated with a shipment of plants is not detected by the federal inspectors. The meaning of this finding is unclear because the study did not include any plant genera native to temperate North America and APHIS points out that infestation rates varied considerably among genera in the study. However, APHIS has not conducted its own analysis to document the “slippage rate” on imports of greatest concern to forest conservationists, i.e., imports of woody plants. I provide details on pests detected on imports of woody plants in recent in my blog here.
Clearly the risk of pest introductions continued at least until recently. I reviewed an APHIS database listing pests newly detected in the country during the period 2009-2013. I concluded that approximately 37 of the 90 “new” pests listed in the database (viruses, fungi, aphids and scales, whiteflies, mites) were probably introduced via imports of plants, cuttings, or cut foliage or flowers. I discussed these matters in greater detail here.
Adoption of a new regulatory regime governing imported plants for planting (Q-37 regulation) in 2018 is too recent to for us to see its impact. But the new regulation sets up a process under which APHIS can impose more protective regulations on specific types of plants or plants from certain countries of origin to counter a perceived concerning level of risk. Until APHIS begins activating its new powers by negotiating more protective regulations governing plant imports from high-risk sources, it seems unlikely there will be any meaningful change in the introduction rates.
Crates, Pallets,
and Other Forms of wood packaging (solid wood packaging, or SWPM)
Recognition
of the risk associated with wood packaging is much more recent. In 1982, a USDA
risk assessment concluded that the wood boring insects found in crates and
pallets were not of great concern (USDA APHIS and Forest Service, 2000).
However, contradictory indications were quickly documented – including from
APHIS’ own port interception data – which the agency began collecting in 1985. Over
the 16-year period 1985-2000, 72%
of
the 6,825 bark beetles (Scolytidae)
intercepted by APHIS were found on SWPM (Haack 2002). Cerambycids (longhorned
beetles) and buprestids (jewel beetles) make up nearly 30% of insects detected
in wood packaging over the last 30 years (Haack et al. 2014).
Detection
of outbreaks of the Asian longhorned beetle and other woodborers in the
mid-1990s made it clear that wood packaging was, indeed, a high-risk pathway.
Of
the 91 most damaging non-native pest species in the US, 30% probably arrived
with wood packaging material or other wood products (Liebhold et al. 2012). This group includes many
of the most damaging pests, the deadly woodborers – Asian longhorned beetle,
emerald ash borer, redbay ambrosia beetle,
possibly the polyphagous and Kuroshio shot hole borers.
CBP agents inspecting a pallet
As noted above, introductions of wood borers have risen in recent decades, widely accepted as associated with the rapid increase in containerized shipping after 1980. In 2009 it was estimated that 75% of maritime shipments were packaged in crates or pallets made of wood (Meissner et al. 2009). A good history of the global adoption of containerized shipping is Levinson, M. The Box: How the Shipping Container Made the World Smaller and the World Economy Bigger (Princeton University Press 2008)
The simultaneous
opening of trade with China (in 1979) offered opportunities for pests from a
new source country which has a similar climate and biology. Chinese-origin wood-boring
pests began to be detected around 1990. This already short interval probably underestimates
how quickly pests began arriving; detection methods were poor in those years,
so a pest was often present for close to a decade before detection.
I have already documented numerous times that, despite the U.S.’ implementation of the International Standard of Phytosanitary Measures (ISPM) #15 in 2006, live quarantine pest woodborers continue to enter the U.S. in wood packaging. The best estimate is that 0.1% of wood packaging entering the United States is infested with wood-borers considered to be quarantine pests (Haack et al. 2014). More than 22 million shipping containers entered the U.S. via maritime trade in 2017 (US DoT). As noted, an estimated 75% of sea-borne containers include wood packaging. Applying the 0.1% estimate to these figures results in an estimate that as many as 17,650 containers per year (or 48 per day) transporting tree-killing insects enter the U.S.
Over a period of
nine years – Fiscal Years 2010 through 2018 – U.S. Customs and Border
Protection (CBP) detected more than 28,600 shipments with wood packaging that
did not comply with ISPM#15 (Harriger presentations to the annual meetings of
the Continental Dialogue on Non-Native Forest Insects and Diseases). While most
of the non-compliant shipments were wood packaging that lacked the required
mark showing treatment per ISPM#15,
in 9,500 cases the wood packaging actually harbored a pest in a regulated
taxonomic group.
Disturbingly, 97%
of the shipments that U.S. CBP found with infested wood packaging bear the
ISPM#15 mark certifying that wood had been fumigated or heat-treated (Harriger
2017). CBP inspectors tend to blame this on widespread fraud in use of the mark.
On the other hand, one study found that larvae can survive both treatments –
although the frequency of survival was not determined. It was documented that twice
as many larvae reared from wood treated by methyl bromide fumigation survived
to adulthood than larvae reared from heat-treated wood; the reason is unclear
(Nadel et al. 2016).
The APHIS’ record
of interceptions for the period FYs 2011 – 2016 contained 2,547 records for
insect detections on wood packaging. The insects belonged to more than 20
families. Families with the highest numbers of detections were Cerambycids –
25% of total; Curculionidae – 23% (includes Dendroctonus,
Ips, Orthotomicus, Scolytinae, Xyleborus, Euwallacea); Scolytidae – 17% (includes
true weevils such as elm bark beetles); Buprestids – 11%; and Bostrichidae –
3%. Not all of the insects in these groups pose a threat to North American
plant species.
One encouraging data point is that since 2010, there have been no detections of species of bark and ambrosia beetles new to North America in the traps deployed by the USDA Forest Service Early Detection and Rapid Response program (Rabaglia 2019). The 2014 recognition of the Kuroshio shothole borer apparently did not result from this trapping program.
There have been several changes in the wood packaging standard and its implementation by CBP since 2009, the year Haack et al. 2014 analyzed the “pest approach rate”. APHIS has not carried out a study to determine whether these recent changes have reduced the approach rate below Haack’s estimate of 0.01%. Consequently, we do not know whether these changes have reduced the risk of pest introductions.
Other Pathways That
Transport Fewer Pests – Some of Which Have High Impacts
Insects
that attach egg masses to hard surfaces can be transported by ship
superstructures, containers, and hardsided cargoes such as cars, steel beams,
and stone. While relatively few species have been moved in this way, some have
serious impacts. The principal examples are the gypsy moths from Asia, which
feed on 500 species of plants (Gibbon 1992).
The United States and Canada have a joint program – under the auspices of the North American Plant Protection Organization (see RSPM #33) aimed at preventing introduction of species of Asian gypsy moths. The NAPPO standard originally went into force in March 2012. Under its terms, ships leaving ports in those countries during gypsy moth flight season must be inspected and cleaned before starting their voyage.
Gypsy moth populations rise and fall periodically; it is much more likely that egg masses will be attached to ships during years of high moth population densities. These variations are seen in U.S. and Canadian detection reports – as reported here.
While most AGM detections are at West Coast ports, [here; and here] the risk is not limited to that region. AGM have been detected at Wilmington, NC; Baltimore, MD; Charleston, SC; Savanna and Brunswick, GA; Jacksonville, FL; New Orleans, LA; Houston and Corpus Christi, TX; and even McAlester, OK.
Nor is the risk limited to the ships themselves. In 2014, more than 500 Asian gypsy moth egg masses were found on four shipments of imported steel slabs arriving at ports on the Columbia River in Washington.
Between 1991 and 2014, AGM was detected and eradicated
on at least 20 occasions in locations across the United States (USDA AGM pest
alert). Additional outbreaks have been discovered and eradication efforts
undertaken in more recent years.
A second example is
the spotted lanternfly (SLF) (Lycorma delicatula), which was first
detected in southeast Pennsylvania in autumn 2014. It is native to Asia; it is
believed to have entered the country as egg masses on imported stone.
While SLF is
clearly a pest of agriculture – especially grapes and tree fruits – its
importance as a forest pest is still unclear. Many native forest trees appear
to be hosts during the insect’s early stages, including maples, birches,
hickories, dogwoods, beech, ash, walnuts, tulip tree, tupelo, sycamore, poplar,
oaks, willows, sassafras, basswood, and elms. Adult lanternflies strongly
prefer the widespread invasive species tree of heaven (Ailanthus altissima).
As of August 2019, SLF was established in parts of five states: Delaware, Maryland, New Jersey, Pennsylvania, and Virginia. It was detected as having spread to a 14th county in Pennsylvania; five new counties in New Jersey. APHIS is working with state departments of Agriculture in these states, as well as supporting surveys in New York, North Carolina, and West Virginia (USDA APHIS DA-2019-20, August 7, 2019). Apparently the detections of a few adults – alive or dead – in Connecticut and New York had not evolved into an outbreak. See description and map here.
Imports of logs – roundwood – seem inherently risky. Certainly Dutch elm disease was introduced via this pathway. However, there have been few pest introductions linked to this pathway in recent years, probably because we import most of our unprocessed lumber from Canada. (I provide considerable data on U.S. roundwood imports in Fading Forests III here.)
Decorative items and furniture made of unprocessed wood certainly have the potential to transport significant pests (USDA APHIS 2007). Examples include boxes and baskets; wood carvings; birdhouses; artificial Christmas trees or other plants; trellises; lawn furniture. To date, apparently, no high-impact pest has been introduced via this pathway, although pests intercepted on shipments have included Cerambycids from Asia, e.g., velvet longhorned beetle and here.
Alarmed by high numbers of infested shipments from China, APHIS first suspended imports of such items temporarily; then adopted a regulation (finalized in March 2012 – USDA APHIS 2012).
APHIS
has not taken action to prevent introductions on such items imported from other
countries – although the North American Plant Protection Action adopted a
regional standard making the case for such action and outlining a risk-based
approach (NAPPO RSPM#38).
Snails on Shipping
Containers
Snails have been
detected on shipping containers and wood packaging for decades. In 2015, APHIS
stepped up its efforts to address this risk through bilateral negotiations with
Italy and launching regional and international efforts to develop guidance for
ensuring pest-free status of shipping containers (Wendy Beltz, APHIS, presentation
to National Plant Board, 2018 annual meeting).
SPREAD
WITHIN THE UNITED STATES
Major pathways for human-assisted spread of pests within the country are sales of plants for planting, movement of unprocessed wood – especially firewood, and hitchhiking on transport vehicles. Since most forest pests are not subject to federal quarantine, any regulatory programs aimed at preventing spread depend on cooperation among the 50 states. None of these pathways is regulated adequately to prevent pests’ spread. See Chapter 5 of Fading Forests III here.
And since neither
federal nor state agencies do significant enforcement of existing regulations,
preventing spread often depends upon pest awareness of, and voluntary
compliance by, individuals and companies.
Even pests subject to a federal quarantine are not prevented from spreading. Plants exposed to the sudden oak death pathogen were shipped to 18 states in spring 2019.
SOD-infected rhododendron plant; Indiana Department of Natural Resources
A collaborative effort by the nursery industry, APHIS, and states (Systems Approach to Nursery Certification, or SANC) is striving to close gaps linked to the standard practice of inspecting plants at the time of shipping, but full implementation of this voluntary program is still years away.
Transport of firewood has been responsible for movement of pests both short distances, e.g., goldspotted oak borer in southern California; and long distances – e.g., emerald ash borer to Colorado. APHIS attempted to develop a certification program but the industry was unable to put one together (see Chapter 5 of Fading Forests III). Current federal and state regulations of firewood are tied to the emerald ash borer quarantine, which APHIS has proposed to terminate. Wood for turning and woodworking has also been linked to movement of pests, e.g., walnut twig beetle/thousand cankers disease from the west to Pennsylvania.
emerald ash borer
Truck transport of a
variety of goods has transported European gypsy moths from the infested areas
in the east to the west coast. Transport of stone probably moved spotted
lanternfly from southeastern Pennsylvania to Winchester, Virginia.
SOURCES
Aukema, J.E., D.G. McCullough, B. Von
Holle, A.M. Liebhold, K. Britton, & S.J. Frankel. 2010. Historical
Accumulation of Nonindigenous Forest Pests in the Continental United States.
Bioscience. December 2010 / Vol. 60
No. 11
Brasier, C.M. 2008. The biosecurity
threat to the UK and global environment from international trade in plants. Plant Pathology (2008) 57, 792-808
Bray, A.M., L.S. Bauer, T.M. Poland,
R.A. Haack, A.I. Cognato, J.J. Smith. 2011. Genetic analysis of emerald ash
borer (Agrilus planipennis Fairmaire)
populations in Asia and North America. Biol. Invasions (2011) 13:2869-2887
Gibbon,
A. 1992. “Asian Gypsy Moth Jumps Ship to United States.” Science.
Vol. 235. January 31, 1992.
Haack R. A. and J.F. Cavey. 1997.
Insects Intercepted on Wood Articles at United States Ports-of-Entry and Two
Recent Introductions: Anoplophora
glabripennis and Tomicus piniperda.
In press in International forest insect workshop proceedings, 18 – 21
August 1997, Pucon, Chile. Corporacion National Forestal, Santiago, Chile.
Haack, R.A., F. Herard, J. Sun, J.J.
Turgeon. 2010. Managing Invasive Populations of Asian Longhorned Beetle and
Citrus Longhorned Beetle:A Worldwide Perspective. Annu. Rev. Entomol. 2010.
55:521-46.
Haack,
R.A. and R.J. Rabaglia. 2013. Exotic Bark and Ambrosia Beetles in the USA:
Potential and Current Invaders. CAB International 2013. Potential Invasive
Pests of Agricultural Crops (ed. J. Peña)
Haack R.A., Britton K.O., Brockerhoff, E.G., Cavey, J.F.,
Garrett., L.J., 2014. Effectiveness of the International Phytosanitary Standard
ISPM No. 15 on Reducing Wood Borer Infestation Rates in Wood Packaging Material
Entering the United States. PLoS ONE 9(5): e96611.
doi:10.1371/journal.pone.0096611
Haack,
R.A., F. H´erard, J. Sun, and J.J. Turgeon. 2010. Managing Invasive Populations
of Asian Longhorned Beetle and Citrus Longhorned Beetle: A Worldwide
Perspective. Annu. Rev. Entomol. 2010. 55:521–46
Harriger, K. Department of Homeland Security Bureau of
Customs and Border Protection, presentation to the Continental Dialogue on
Non-Native Forest Insects and Diseases, November 2017.
Jung T, Orlikowski L, Henricot B, et al. 2016. Widespread
Phytophthora infestations in European nurseries put forest, semi-natural and
horticultural ecosystems at high risk of Phytophthora diseases. Forest
Pathology 46: 134–163.
Liebhold, A.M., E.G. Brockerhoff, L.J. Garrett, J.L.Parke, and K.O Britton.
2012. Live plant inports: the major pathway for forest insect and pathogen invasions of the US. Frontiers in
Ecology.
Lovett, G.M., M. Weiss, A.M. Liebhold, T.P. Holmes, B.
Leung, K.F. Lambert, D.A. Orwig, F.T.
Campbell, J. Rosenthal, D.G. McCullough, R. Wildova, M.P. Ayers, C.D. Canham,
D.R. Foster, S.L. LaDeau, and T. Weldy. 2016.
Non-native forest insects and pathogens in the United States: Impacts
and policy options. Eological
Applications, 26(5) pp. 1437-1455.
Meissner, H., A. Lemay, C. Bertone, K. Schwartzburg, L.
Ferguson, and L. Newton. 2009. EVALUATION OF PATHWAYS FOR EXOTIC PLANT PEST
MOVEMENT INTO AND WITHIN THE GREATER CARIBBEAN REGION. Caribbean Invasive
Species Working Group (CISWG) and Plant Epidemiology and Risk Analysis
Laboratory (PERAL) / CPHST. June 4, 2009
Morin, R. presentation at Northeastern Forest Pest Council 81st Annual
Meeting, March 12 – 14, 2019, West
Chester, Pennsylvania
Nadel, N., S. Myers, J. Molongoski, Y.
Wu, S. Linafelter, A. Ray S. Krishnankutty, and A. Taylor. 2016.
Identificantion of Port Interceptions in Wood Packaging Material: Cumulative
Progress Report, April 2012 – August 2016
Rabaglia,
R.J., A.I. Cognato, E. R. Hoebeke, C.W. Johnson, J.R. LaBonte, M.E. Carter, and
J.J. Vlach. 2019. Early Detection and Rapid Response. A Ten-Year Summary of the
USDA Forest Service Program of Surveillance for Non-Native Bark and Ambrosia
Beetles. American Entomologist Volume 65, Number 1
Roy, B.A., H.M. Alexander, J. Davidson,
F.T. Campbell, J.J. Burdon, R. Sniezko, and C. Brasier. 2014. Frontiers in Ecology 12(8): 457-465
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https://www.ippc.int/ Accessed December
7, 2012.
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States.
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Plant Health Inspection Service 2009. Proposed Rule Importation of plants for
planting: establishing a category of plants for planting not authorized for
importation pending pest risk assessment. Federal
Register 74(140): 36403-36414 July 23, 2009.
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Regulations Vol. 83, No. 53. Monday, March 19, 2018
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Plant Health Inspection Service 2007. Pests and
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importation into the United States. Revision 6. July.
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Plant Health Inspection Service. 2012. Importation of wooden handicrafts from
China. Final rule. Federal Register 77(41):
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Accessed August 2, 2013.
United
States Department of Transportation Bureau of Transportation Statistics Freight
Facts and Figures
United States Department of Transportation, Maritime
Administration, U.S. Waterborne Foreign Container Trade by U.S. Customs Ports
(2000 – 2017) Imports in Twenty-Foot Equivalent Units (TEUs) – Loaded
Containers Only
Williams, L.H. and J.P. La Fage. 1979.
Quarantine of Insects Infesting Wood in International Commerce. in J.A.
Rudinksy, ed. Forest Insect Survey and Control Fourth Edition 1979
Wu,Y.,
N.F. Trepanowski, J.J. Molongoski, P.F. Reagel, S.W. Lingafelter, H. Nadel1,
S.W. Myers & A.M. Ray. 2017. Identification of wood-boring beetles
(Cerambycidae and Buprestidae) intercepted in trade-associated solid wood
packaging material using DNA barcoding and morphology Scientific Reports 7:40316
dead whitebark pine in Crater Lake National Park photo by F.T. Campbell
I began studying and writing about the threat to North America’s forests from non-native insects and pathogens in the early 1990s – nearly 30 years ago. I reported my analyses of the evolving threat in the three “Fading Forests” reports – coauthored by Scott Schlarbaum – in 1994, 2003, and 2014. These reports are available here.
So what has changed over those 30 years? What remains the same? Why have both the changes and the stasis occurred? What can we do to fix the gaps, close unaddressed pathways, strengthen flabby policies? I will address these issues in this and following blogs.
experimental American chestnut planted in Fairfax County, VA photo by F.T. Campbell
What has changed
since the early 1990s:
Adoption and implementation of significant new international and national regulations and programs aimed at preventing introductions of non-native invasive species.
Despite the welter of new regulations, an alarming increase in numbers of highly damaging forest pests established in the country. (By my count, about 50 new species have established on the continent, six on Pacific islands; see details below.)
Alarming spread of established pests to new geographic regions and new hosts (e.g., emerald ash borer in 35 states and 5 provinces; laurel wilt disease across the range of redbay and swamp bay; rapid ‘ōhi‘a death on three of the main Hawaiian islands).
Introductions via unexpected pathways and vectors far removed from phytosanitary agencies’ usual targets, e.g., ship superstructures, imported steel and stone …
What has remained the
same since the early 1990s:
Inadequate
resources provided to response and recovery efforts.
Available
funding focused on only a few of the more than 90 species causing damage.
Adoption
of insufficiently protective regulations that have failed to prevent
introduction and spread of tree-killing pests.
Lengthy
delays in implementing programs that tighten controls – another factor in
continuing introductions and spread.
Continued
importance of expected pathways – nursery stock and raw wood, especially
crates, pallets, and other forms of wood packaging.
Federal
and state agencies still choose not to take action on pests e.g., goldspotted oak borer, polyphagous
and Kuroshio shothole borers, beech leaf disease.
Inadequate
coordination despite several efforts to set priorities.
Spurts
of attention by media and political decision-makers, contrasted by lengthy
periods of inattention.
Failure
of most stakeholders to support efforts to prevent and respond to introductions
of tree-killing pests.
Details: The Situations
Then and Now
(Many of the individual species mentioned here are described more fully here. Full citations of sources are at the end of blog.)
American elm on the National Mall, Washington, D.C.
photo by USDA Agricultural Research Service
In 1993:
The number of non-native forest pest species established in the U.S. was estimated at between 300 (Millers et al. 1993) and 380 (Mattson et al., 1994; Liebhold et al., 1995) .
The area suffering the greatest numbers and impacts was the Northeast.
Several highly damaging pests that had been established for decades, including chestnut blight, white pine blister rust, Port-Orford-cedar root disease, Dutch elm disease, hemlock woolly adelgid, butternut canker, and dogwood anthracnose were receiving some attention but continued to spread.
USDA Forest Service funding for management of exotic pest infestations was crisis-oriented, with “… priorities … set under political pressures for immediate answers, with too much regard for short-term problems and too little consideration for broader management objectives.” (NAS 1975)
Since few high-profile pests had been introduced in recent years, APHIS was not actively engaged. In FY92, APHIS spent $20 million on efforts to eradicate the Asian gypsy moth. The narrow focus is illustrated by the fact that in FY93, more than two-thirds of all USDA tree pest control funds were devoted to efforts to suppress or eradicate the European gypsy moth (See FFI).
Concern about possible new introductions had grown; it focused on proposals to import unprocessed wood from Siberia, New Zealand, and Chile. The USDA Forest Service, academic scientists, and therefore APHIS emphasized the risks of known Asian pests, e.g., Asian gypsy moth, to western coniferous forests (See FFI). While individual scientists had expressed concern about wood packaging material, there was little public discussion of this threat.
We would learn later that several of the most damaging pests were already present in the country but not yet recognized – Asian longhorned beetle, sudden oak death pathogen, probably emerald ash borer.
beech leaf disease
photo by John Pogacnik
In 2019:
Numbers of non-native insects and pathogens attacking trees in North America approach 500 species. (In Fading Forests III, I calculated that by the first decade of the 21st Century, the number had risen to at least 475. Several more have been detected since 2014. More than 181 exotic insects that feed on woody plants had established in Canada. (Source: USDA APHIS. 2000. Wood packaging risk assessment.)
Of these, 91 are considered “serious” threats (Guo et al. 2019). This estimate excludes pests native to portions of North America that are causing severe damage in naïve hosts – e.g., goldspotted oak borer; pests of palms; and pests attacking trees on U.S. Pacific and Caribbean islands.
Introductions had continued.
Between 1980 and 2016, at least 30 non-native species of wood- or bark-boring insects (Scolytinae / Scolytidae) were newly detected in the U.S. (Haack and Rabaglia 2013; Rabaglia et al. 2019). A few of these are highly damaging, e.g. redbay ambrosia beetle, polyphagous and Kuroshio shothole borers.
In addition to these 30 new pests, other highly damaging tree-killing pests probably introduced since the 1980s include (on the continent):
Eight Cerambycids such as Asian longhorned beetle (Wu et al. 2017)
7 Agrilus, including emerald ash borer and soapberry borer; plus goldspotted oak borer transported from Arizona to California (Digirolomo et al. 2019; R. Haack, pers. comm.)
Sirex woodwasp
Pests of palm trees, e.g., red palm mite, red palm weevil, South American palm weevil
Spotted lanternfly
Beech leaf disease
Also not included in the above estimate and lists are tree-killing pests on America’s Pacific Islands :
‘ōhi‘a rust
Cycad scale
Cycad blue betterfly
Erythrina gall wasp
two Ceratocystis pathogens that cause rapid ‘ōhi‘a death
Coconut rhinoceros beetle
Authorities also carried out approximately 25 eradication programs targetting introductions of the Asian gypsy moth (USDA Pest Alert Asian Gypsy Moth plus additional outbreaks since 2014).
Impacts of exacerbated tree mortality rates linked to these introduced pests are seen across wide swaths of the country, and affect widespread species, genera, and families.
dead redbay in Claxton, Georgia photo by Scott Cameron
I will discuss the risk of continuing new introductions in a separate blog.
Trying to Develop
the Big Picture and Set Priorities
In
recent years, USDA Forest Service scientists have made several attempts to
provide nation-wide assessments of the impact of these pests and criteria for
establishing priorities.
The
National Insect and Disease Forest Risk Assessment predicted the loss of basal
area to various pests over the 15-year time period 2012 – 2027. The assessment
predicted the following losses for specific species: 90% for redbay; 60% for whitebark
pine; more than 40% for limber pine; 24% for tanoak; 11% for coast live oak; 6%
for eastern and Carolina hemlock; 27% for eight species of ash; 20% for
American elm; 19% for red oak; 18% for American beech (Krist et al. 2014).
A separate group of scientists found that, nation-wide, non-native forest pests are causing an approximate 5% increase in total mortality by tree volume (Randy Morin at NEFPC). For details on Dr. Morin’s findings, see my blog here.
A third approach to developing a nation-wide picture, Project CAPTURE, (and my blog here) utilized FIA data to develop priorities for conservation action. Fifteen species were placed in the highest priority category, including Florida torreya (Torreya taxifolia), American chestnut and Allegheny and Ozark chinquapins, redbay, five species of ash, two species of hemlock, Port-Orford cedar, tanoak, and butternut (Potter et al. 2019(b).
According
to Project CAPTURE, the non-native pests affecting the largest number of hosts
are the European gypsy moth, which attacks 65 hosts; and oak wilt (Bretziella fagacearum), which infects 61
hosts. The Asian longhorned beetle attacks 43 hosts (Potter et al. 2019(b).
I note that several other non-native pests also have high numbers of host species. In the Project CAPTURE study, these pests are ranked lower because the project limited its evaluation to the five agents with the greatest effect on any particular host. Thus, of the 18 native tree species that host one or both of the invasive shothole borers and associated Fusarium disease complex (PSHB website), the project included only six. Of the 22 tree species listed by APHIS as hosts of Phytophtora ramorum, the project included 12 (K. Potter, pers. comm. April 17, 2019).
SOD-killed tanoak on the Big Sur peninsula, California photo by Matteo Garbelotto, University of California Berkeley
More extensive discussions of
non-native pests’ impacts are provided in Lovett et al. 2006, Lovett et al.
2016, and Potter et al. 2019. A
book-length discussion of invasive species impacts – ranging from feral hogs to
invasive plants, is expected in December; look for Poland et al. (in press).
SOURCES
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rhododendron infected by P. ramorum; photo by Indiana Department of Natural Resources
Sudden
oak death (SOD) (Phytophthora ramorum)
As I reported in June, Indiana officials had detected the pathogen that attacks more than 100 plant species and that causes sudden oak death in shipments of rhododendron plants from two nurseries in Washington State and British Columbia.
After an unexplained delay, USDA APHIS finally issued an official statement (reported on here) on the situation. Shipments of potentially infected plants already had been sent to 18 states — Alabama, Arkansas, Iowa, Illinois, Indiana, Kansas, Kentucky, Michigan, Missouri, Nebraska, North Carolina, Ohio, Oklahoma, Pennsylvania, Tennessee, Texas, Virginia, and West Virginia. Through “trace forward” inspections, eight of those states have confirmed that their plant retailers received infected plants — Iowa, Illinois, Indiana, Kansas, Missouri, Nebraska, Oklahoma, and Washington.
Plants that test positive for P.
ramorum are being destroyed. All plants that have been kept within a
two meter radius of an infected plant are also being destroyed. Host plants
outside the two meter radius will be sampled intensively.
In addition, several major retailers have agreed
to initiate a voluntary recall of plants from their stores.
APHIS advises
people in these eighteen states who have bought a
rhododendron from a retail outlet to monitor the plant for signs of disease,
including leaf spots and shoot dieback. (APHIS provides no reference to a
reliable on-line source of information on symptoms.) If people suspect their
plant(s) might have the disease, they are advised to contact their local state
department of agriculture or a county extension office.
Meanwhile, states are taking steps to inform their citizens. I described the rapid and extensive effort in Indiana in my earlier blog. In Kansas, the Department of Agriculture announced the presence of the pathogen on rhododendron containerized plants on June 7. As in Indiana, most of the plants were being sold by Walmart stores; also one by Home Depot.
In Illinois, state officials announced the pathogen’s presence on July 2nd. Infected plants were detected at ten Walmarts and at one Hy Vee. Walmart and Rural King are participating in voluntary recalls.
It
is unlikely that all the infected plants have been or will be detected and destroyed
according to protocols. First, some plants had undoubtedly been sold to people
who remain unaware of the issue. Second,
other plants were destroyed before they could be inspected by authorities. For
example, Virginia authorities told me that the “original suspect plants” at a
retail store had been destroyed before they arrived. As a result, authorities
cannot know whether infected plants entered the state.
So, is this response adequate? Who will continue outreach to possible purchasers of the plants? Who will enhance monitoring of native vegetation in vulnerable areas, e.g., the Ozarks of Missouri (see the risk maps on pages 86-88 of Fading Forests III, available here.
The Washington State nursery was operating under the program adopted by Federal Order in 2014 and formalized by the regulatory change last year. Because the Washington state nursery had not previously been detected to have infested plants, it was subject only to the standard state phytosanitary inspections with no special attention to possible sources of Phytophthora ramorum inoculum (on plants, in soil or water, in pots that have been used previously, …). Clearly this system was insufficient in this case – as it had been 15 years ago. I do not know what regulations governed the British Columbia nursery or whether plants from BC are inspected more closely by APHIS when they are imported.
I repeat – what lessons
will APHIS learn from this disturbing event, and how will it adjust its
program? Will the states – 18 of which had to carry out expensive trace-forward
programs – demand a more rigorous program?
Beech leaf disease (BLD)
beech leaves with symptoms; photo by John Pogacnik, Cleveland Metroparks
In January I posted a blog about beech leaf disease. In May and June, two people commented, raising the question of whether BLD was killing trees on their properties in Connecticut. Connecticut’s authorities have visited at least one of these sites, but I have heard nothing about their findings. Photographs from the first site, however, greatly worried Ohio’s experts.
More
recently, a person in Westchester County, NY (which borders Connecticut) also
raised the alarm. I don’t know whether New York authorities (some of whom have
viewed symptomatic trees in western New York and Ohio) have checked this site.
Although
these reports have not yet been verified by authorities, I think it would be
wise for people throughout the range of American beech – or who have bought
European beech trees in recent years from Ohio nurseries – to closely monitor their
trees and report any suspicious findings to state authorities.
Posted
by Faith Campbell
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