SOD in the East

At present, sudden oak death (SOD) is killing trees and shrubs in forests along the Pacific coast from far southern Oregon to Monterey County in California – a stretch of more than 400 miles.

However, numerous tree and shrub species native to forests in the East also are vulnerable to the pathogen. These include several oak trees (northern red, chestnut, white, and pin oaks), sugar maple, black walnut; and such shrubs as mountain laurel and rhododendrons.

While no infestations of SOD have been found in the wild in the East, the pathogen is already present in some nurseries and continues to be transported to disease-free parts of the Southeast in shipments of nursery plants – as described in my previous blog.

Nine eastern states monitor streams to detect the pathogen in water. These states are AL, FL, GA, MS, NC, NY, PA, SC, & TX. As of 2013, six states had detected the pathogen in a total of 11 streams and ponds; all were outside nurseries that had previously had infested plants. These positive streams were distributed as follows: AL-4; FL-1; GA-2; MS-1; NC-1; TX-2.

In 2014, only four states (instead of six) detected the SOD pathogen in at least one stream: AL-4; FL-1; MS-2; and NC-2. Two of these streams were new – one each in AL and FL.

One of the AL detections is in a stream associated with a nursery that had not previously been determined to have infested plants. Authorities plans to sample vegetation near this stream. In the past, once a stream had tested positive, it remained positive in all subsequent years. However, the testing methods are not perfect so some variation in findings can be expected.

Infested plants were found growing in the ground (outside a nursery) at three sites: one each at homes in CT and MA; and a commercial business site in LA. These searches were undertaken because officials knew that these residents or businesses had bought plants from an infested nursery in earlier years.

As noted in my previous blog, SOD has been detected in eight nurseries in the East: ME-1, NY-2, TX-1, VA-4). The TX nursery became infested by plants received from a California nursery. I am very concerned about the presence of the pathogen in four Virginia nurseries, because the Commonwealth falls in the geographic region thought to be most vulnerable to the pathogen [see risk maps in the SOD writeup at or in Chapter 5 of Fading Forests III.

Is the Government Preventing Movement of Sudden Oak Death (SOD) to Vulnerable Areas in the East?

Are the Rules Working?

APHIS adopted a new approach to regulating interstate trade in SOD hosts in early 2014. One year later, spring 2015, it is too soon to provide a thorough evaluation of whether this approach is effective in ending the risk that the disease will be moved to new areas on nursery plants. But some problems have already shown up, suggesting that the approach has serious weaknesses and will not succeed as intended.

1) APHIS’s new program is unlikely to find either new or cryptic infestations quickly.

When APHIS put its program into force in March 2014, 23 nurseries in California, Oregon, and Washington that had tested positive for the pathogen in the previous three years signed up to participate in the program – thus complying with the requirements for continuing to ship SOD host plants interstate. By the end of 2014, three of those nurseries had dropped out – so they can now ship plants only to retailers/purchasers within their states. A fourth nursery was expelled from the program because of its continuing inability to eradicate the pathogen from its premises. This nursery is no longer allowed to ship SOD hosts out of state.

At the same time, two additional nurseries joined the program. So as of the end of 2014, 21 nurseries were participating. Seven participating nurseries are in California; all have tested free of the pathogen in spring 2015. Ten participating nurseries are in Oregon; four of these nurseries tested positive for the pathogen in spring 2015.

Many more nurseries in the three states that had been tested for the pathogen over the past three years and found not to be infested are now allowed to ship plants interstate without being subject to the new APHIS requirements. (For example, in 2013 California tested plants in 1,575 nurseries; only one positive nursery was found.) The issue now is whether these nurseries are truly clean of the pathogen, and will remain so. Since the SOD pathogen was extremely difficult to detect in plants (the system relied upon before 2014), I am concerned that nurseries that tested “clean” before 2014 might have harbored a cryptic infestation that escaped detection.

Such cryptic pre-existing infestations – and any new infestation that establishes in a nursery not currently subject to the regulation due to a previous infestation – will probably escape detection for months because, under the current APHIS program, the presence of SOD in these nurseries will be detected only under one of the following conditions:

  • The nursery owner reports symptoms of infestation;
  • The state detects symptomatic plants during a routine state inspection; or
  • The nursery is identified as the source of infested plants purchased by someone (this is called a trace-back investigation).

Some nurseries that had been shipping SOD host plants interstate under the previous APHIS regulations chose to stop shipping host plants interstate and so did not agree to abide by the new requirements. I know that five Oregon nurseries opted out; APHIS has not told me how many nurseries in California and Washington also opted out.

SOD Parke diseased plant

picture of infested rhododendron plant;

courtesy of Jennifer Parke, Oregon State University

  • The risk that nursery plants will spread SOD continues.

How large is this risk? One measure is how many nurseries are infested with the disease – either through a new introduction or as a result of an earlier infestation that was not detected.

During 2014, state inspectors detected the SOD pathogen in 19 nurseries – almost the same number as in 2013, and slightly more than half the number in 2012. (For a discussion of the SOD pathogen in nurseries in recent years, read Chapter V in Fading Forests III. Eleven of these nurseries were in the three west-coast states that have been regulated most tightly in the past (CA-1, OR-8, WA-2); eight nurseries were in other parts of the country (ME-1, NY-2, TX-1, and VA-4).

Fourteen of the 19 nurseries had tested positive for the pathogen during the previous three years. Consequently, they had been subject to the new regulation from its implementation.

However, two nurseries had tested positive before 2011, but not during the key 2011-2013 period. Under the terms of the 2014 regulation, these nurseries were not subject to APHIS’s new regulation and they continued to ship plants. This raises concerns about whether infestations in some nurseries might not be detected under the new regime before they ship plants to disease-free areas.

Eight of the 19 infested nurseries were interstate shippers (CA-1; OR-4; WA-1; TX-1; VA-1). Six had shipped plants in the previous six months.

Five of these infested interstate shippers stayed in the new APHIS program, carried out Critical Control Point Assessments, and adopted specific mitigation actions that were approved by APHIS and state officials. They continue to ship SOD host plants interstate.

Four of the eight infested nurseries left the program, either voluntarily or by compulsion. Nurseries not in the APHIS program may now ship SOD host plants only to destinations within their states; they are subject to regulation by their state agencies (usually, departments of agriculture).

Eleven of the nurseries detected to be infested by the SOD pathogen in 2014 shipped only to retailers within their own states; these nurseries are regulated by the appropriate state rather than by APHIS.


Strengths and Weaknesses of the New Regime

 So, what do I see as the strengths of the new regulatory regime? Most important, inspectors test the soil, water, and pots, not just symptomatic plants. This approach, recommended by scientists for years before APHIS adopted it, is paying off: inspections detected the pathogen twice in potting media, six times in a nursery’s soil, and 15 times in water on nursery premises.

The greatest weakness is the three-year cutoff for including nurseries in the APHIS program; as demonstrated already, nurseries can be clean for three years and then again be found to be infested. It has always been difficult to determine whether these “repeat” nurseries were infested all along, but somehow escaped detection; or have become infested through a new introduction of the pathogen.

Questions also arise because of the reliance on state regulation of nurseries shipping only within the state. Some state agencies appear to be much more aggressive than others in searching for symptoms of infestation and requiring cleanup.

Another possible problem is that the regulatory inspection effort focuses on five genera — Camellia, Kalmia, Pieris, Rhododendron, and Viburnum — but plants in other genera are also hosts. During 2014, detections were made on the following genera that are not among the “high-risk” hosts — Gaultheria, Prunus, Syringa and Vaccinium; and seven new host species were detected in the forest or in nurseries. One of these apparently new hosts, Vinca, is a widely planted ground cover (“periwinkle”) shipped in flats of often sad-looking rooted cuttings.

One good sign is that the nursery trade and state agricultural agencies are seeking ways to decrease the movement of plant pests via the nursery trade. Examples of such pest movement are not limited to SOD or other tree-killing pests; for example, boxwood blight was first detected in the United States in 2011; by 2013 it was known to be in nine eastern states and Oregon.

The nursery trade (through their trade associations, AmericanHort and the Society of American Florists), state agencies, and APHIS have developed a voluntary program called Systems Approach to Nursery Certification, or SANC. The collaborating organizations devoted several years to developing an agreed-upon set of standards and procedures aimed at making their facilities as free of disease and pests as possible. Now they are testing whether the program works in practice. Eight plant growers from across the country – and the appropriate state agencies – have agreed to:

  • Assess the facility for situations and practices that create a risk of pest infestation;
  • Identify best management practices that will mitigate those risks; and
  • Develop new facility-management manuals that apply those practices.

The SANC managers expect the pilot program to take 3 years (2018).

The principal sources for the information in this blog are the monthly newsletters prepared by the California Oak Mortality Task Force (COMTF), found at and the USDA APHIS program updates found at

Funding Shortfalls Threaten Our Trees – & Are Becoming Worse

Experts have recognized for two decades that funding of federal programs intended to prevent or respond to introductions of invasive species is inadequate.  As regards tree-killing insects and pathogens, there have been spikes in the past, spurred by, first, detection of Asian longhorned beetle  and emerald ash borer, then by federal spending increases to support recovery from the Great Recession.

But with renewed pressure to reduce the federal budget, programs operated by APHIS and the USDA Forest Service have suffered significant cuts in spending. For a history of these cuts, read Chapter 3 in Fading Forests III .

Funding for key programs continue. Most alarming is that these cuts are suggested by the Administration! in its annual budget sent to Congress. I don’t know whether the cuts are suggested by the agencies, or instead are imposed by higher-ups in the Department of Agriculture or at the President’s Office of Management and Budget.

White House

Certainly there is competition for the available funds. APHIS is funded by the Agriculture Appropriations bill, which also funds agriculture programs that enjoy strong lobbying support as well as food stamps. The Forest Service is being squeezed by the ever-higher costs of managing wildfires.

Still, these cuts threaten to expose our wildland, rural, and urban forests to permanent destruction by non-native, tree-killing insects and pathogens.

Congress determines the final funding levels through the appropriations process.

Capitol  Members of Congress work for us!!

Ask your member of Congress & senators to support adequate funding for APHIS & USFS programs that counter invasive, non-native tree-killing pests.

Congress’ actions are at the following stage as of the third week in July:


The House Subcommittee on Agricultural Appropriations bill had cut funding for “tree and wood pest” group – although the bill did increase funding for the “specialty crops” program.

In both cases, groups with which I work had asked to maintain the FY15 level.

The Senate bill, adopted by the full Appropriations Committee on 16 July, has restored funding to the “tree and wood pest” line! Possibly because of this increase, it holds the “specialty crops” program funding to the FY15 level.

Funding specifics:

HOUSE Agriculture appropriations bill maintains overall funding for APHIS at the FY15 level ($871 million). This is $15 million above the President’s request in his budget; and about the same as the level of funding for the current fiscal year (FY 2015). Within this amount, the following is allocated to programs that address tree-killing pests:

  • $158,000,000, to remain available until expended, for specialty crop pests

(a very small proportion of this account, about $5 million, goes to sudden oak death management)

  • $45,500,000, to remain available until expended, for tree and wood pests (e.g., ALB, EAB)


SENATE Agriculture appropriations bill raised overall funding for APHIS to $876 M — $20 million above the President’s budget request and $5 M above both the current year and House level. Within this amount, the following is allocated to programs that address for tree-killing pests:

  • $156,000,000, to remain available until expended, for specialty crop pests
  • $54,000,000, to remain available until expended, for tree and wood pests


As I said above, it is disturbing that these programs do not enjoy sufficient support within the Administration. We all need to increase our lobbying of USDA – both at the APHIS level and above; and at OMB.


USDA Forest Service

Both the House and Senate Interior Appropriations subcommittee bills cut USFS funding for both research and forest health management.

The House interior appropriations bill provides only $207 million for research other than Forest Inventory and Assessment. The Senate interior appropriations bill provides $211 million for research other than FIA. Both figures are below the $220 million allocated for the current year (FY2015) and higher levels in previous years.

The House bill provides only $99 million for forest health management (on both federal and non-federal or “coop” lands). The Senate bill provides $100.7 million. Again, both figures are below the $104.6 million provided in FY15 and higher levels in previous years.

Funding for all USFS programs is under extreme pressure by the growing cost of fighting wildfires. Until this problem is resolved, it will be extremely difficult to obtain additional funds for other programs – even in the face of rising numbers of tree-killing pests across the country. There are also questions within OMB and among some advocacy groups about whether the USFS should assist states and cities in containing tree-killing pests. Some argue that the USFS should confine its efforts to pests that are attacking trees in National forests. My reply: if you wait for ALB or other pests to reach National forests before responding, you have thrown away any chance of containing the outbreak.


California Government Ignores Threats to State’s Hardwood Trees

CDFA Fails to Regulate Movement of Firewood

Many of California’s hardwood trees are threatened by two introduced insects – the goldspotted oak borer (or here) and the polyphagous shot hole borer  or here. Both are established in southern California, but threaten trees throughout the state.

GSOB profileOne of the most likely pathways by which these insects can be moved to vulnerable areas is by the transport of firewood. Yet the California Department of Food & Agriculture (CDFA) has not regulated firewood movement.

goldspotted oak borer

Two Tree-Killers

California’s oaks – including California black oak, canyon live oak, coast live oak, Engelmann oak, Shreve’s oak, and valley oak – are threatened by one of both of these insects. The goldspotted oak borer (GSOB) is established in San Diego County with additional outbreaks in Riverside and Orange counties. In less than 20 years, GSOB has killed nearly 100,000 black oaks in these counties. GSOB also kills coast live and canyon oaks. These oaks growing throughout the state are at risk to GSOB.

GSOB FHTET Calif only    areas of California at risk to goldspotted oak borer

The polyphagous shot hole borer (PSHB) carries a fungus. The beetle-disease complex has been found in areas of Los Angeles, Orange, San Bernardino, Riverside, and San Diego counties. The insect attacks more than 300 species of trees, shrubs, and vines; the fungus survives in more than 100 of these.

Trees attacked by PSHB include: 11 species native to southern California; 13 agriculturally important trees, such as avocado; and 53 species that, cumulatively, constitute more than half of all trees planted in urban areas of southern California. While PSHB might not be able to reproduce in all these hosts, it is known to reproduce in five types of maples, five types of oaks, a couple of willows, as well as a poplar, a sycamore, and an alder.

PSHB 14-7 rt way 

areas of southern California where polyphagous shot hole borer is established

Many of the vulnerable tree species are important components of riparian communities in southern California. PSHB apparently attacks only trees that receive enough water to support the fungus – hence the threat to riparian areas. Since PSHB comes from tropical Southeast Asia, its spread to the north and upslope would probably be limited by winter cold. Nevertheless, a wide variety of trees in large parts of the state appear to be at risk.

Among the natural areas at risk to one or both of these pests is Yosemite National Park. The oak trees growing in Yosemite Valley are black oaks, vulnerable to GSOB.

 Both State & National Park Service have Failed to Act

 Despite the threat to natural and even agricultural resources throughout the state, CDFA has not adopted regulations governing the movement of firewood – the pathway most likely to spread these pests. CDFA has funded outreach efforts, including flyers, posters at campgrounds, and highway billboards. Broad coalitions – made up of academics; county agriculture and parks officials; federal forestry and public lands staff; and others –are educating the public and firewood vendors about the risk and asking them not to move firewood. But when people ask whether there is a law against moving firewood, these volunteers must answer, “no”. This undermines their message!

Yosemite and the other National parks in the region also have not adopted regulations prohibiting visitors from bringing in firewood obtained outside the park. While the National Park Service discourages people from bringing firewood into the Park from farther than 50 miles away, this request is buried in the detailed description of camping regulations or here.

The other National parks in California also do not regulate visitors’ movement of firewood.

It is past time for state and federal agencies to accept their responsibility to protect priceless natural and agricultural resources by adopting regulations to control the movement of firewood.

Government Should Act Now! to Shut Wood Packaging Pathway

Revise Decade-Old Policies that Do Not Prevent Introductions

Despite regulations adopted 9 or more years ago, tree-killing insects continue to enter the U.S. in wood packaging. Aggressive enforcement is needed now to prevent further huge ecological and economic losses.

Disasters already introduced via this pathway

As Americans import more stuff, the risk rises that larvae of tree-killing insects will be enter the country hiding in wooden crates, pallets, etc. – called “solid wood packaging” or SWPM.  For more information on this threat, the agencies responsible, and actions taken or proposed, visit here.

Damaging pests still found in SWPM

USDA APHIS (for more information about APHIS, read “Invasives 101” at required treatment of wood packaging from China 15 years ago, and treatment of wood packaging from other trade partners 9 years ago! Yet, a small proportion of incoming wood packaging still carries tree-killing pests. As many as 13,000 shipping containers harboring tree-killing pests probably enter the country each year – or 35 each day. [i] The Asian longhorned (illustrated below) is among the pests still detected in wood packaging from China. [ii]

ALB profile jpg

Cities that import the most goods from Asia are at particular risk – New York, Chicago, Los Angeles and Long Beach. Others are also at risk: Washington, D.C.; Virginia Beach; Jacksonville. [To see a more complete list, visit here]

What the Government Has Done

While USDA APHIS has cracked down on U.S. producers of wood packaging who cheat and is promoting workshops to educate our trade partners on wood packaging treatment requirements (see write-up on referenced above), the government should do more to protect our forests.

What More Can be Done

  • At present, U.S. policy allows an importer to be caught 5 times in 1 year with wood packaging that does not comply with the regulatory requirements. Requirements adopted a decade or more ago should be enforced strictly! The Bureau of Customs and Border Protection and USDA APHIS should instead penalize all importers whose wood packaging does not comply with regulatory requirements.
  • The Bureau of Customs and Border Protection should incorporate the wood packaging requirements into its “Customs-Trade Partnership Against Terrorism” (C-TPAT) program .
  • USDA APHIS should re-examine the economic pros and cons of requiring importers to switch to packaging made from materials other than wooden boards. The new review should incorporate the high economic and ecological costs imposed by insects introduced via the wood packaging pathway.
  • The President’s Office of Management and Budget should allow APHIS to finalize regulations – proposed in 5 years ago! – that would apply the same treatment requirements to wood packaging used in trade between the US and Canada. (Canada has been ready to adopt this measure for several years.)

[i] Haack RA, Britton KO, Brockerhoff EG, Cavey JF, Garrett LJ, et al. (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

[ii] Haack, R.A., F. Herard, J. Sun, J.J. Turgeon. 2009. Managing Invasive Populations of Asian Longhorned Beetleand Citrus Longhorned Beetle: A Worldwide Perspective. Annu. Rev. Entomol. 2010. 55:521-46; these authors report six separate introductions; after the article was published, a seventh was detected in Clermont County, Ohio; and a new outbreak was detected near Toronto, Ontario. Also, Philip Berger, Executive Director PPQ Science and Technology, Presentation to the Continental Dialogue on Non-Native Forest Insects and Diseases, November 3, 2014