Category: forest pest insects

Non-Native Pest Threat to Forests of the West Coast

As we Americans import more stuff, the risk of new pest introductions rises, too. Many tree-killing insects arrive as larvae living in crates, pallets, and other forms of wood packaging. While the USDA requires that incoming wood packaging be treated to prevent pests, this regulation has not prevented pests from entering the country on wood packaging.

piece of wood packaging with Cerambycid larva; detected in Oregon
piece of wood packaging with Cerambycid larva; detected in Oregon

A study has found that perhaps 35 shipping containers harboring tree-killing pests reach our ports each day (Haack et al. 2014). At this rate, in just 35 years, America might suffer invasion by more than 100 new wood-boring species. This would result in a tripling of borers introduced to U.S. (Leung et al. 2014).

Already, wood-boring beetles have been among the most damaging tree-killing pests introduced to the U.S. Our environment certainly doesn’t need invasions by three times as many new wood-borers!

West-coast ports receive lots of incoming shipping containers. Long Beach alone receives about half of the nearly 25 million shipping containers arriving at the U.S. each year. So it is alarming that high-risk insects, including the Asian longhorned beetle (ALB), continue to be found in wood packaging (Berger 2014).

Imported goods that are heavy are more likely to be packaged in wood and that thus pose the greatest pest risk. The highest risk commodities are
• machinery (including electronics) and metals;
• tile and decorative stone (such as marble or granite counter tops) (Harriger 2014).
The west coast ports of Seattle, Los Angeles/Long Beach, and San Francisco all rank in the top 15 out of 3,500 (1/2 of 1%) cities nation-wide for imports of tile and decorative stone, machinery and metals (Colunga-Garcia et al. 2009).

Not only do west coast cities import high volumes of risky goods; a significant proportion of the trees growing in those cities are vulnerable to these pests. Seattle’s three to four million trees belong to more than 300 species – although a mere seven genera constitute two-thirds of the trees (Ciecko et al. 2012). It has been estimated that just four non-native pests (ALB, gypsy moth, emerald ash borer, and “Dutch” elm disease) could cause $3.5 billion in damages. The ALB alone threatens 39.5% of all trees lining the city’s streets (City of Seattle 2013).

San Francisco has an estimated 669,000 trees; 12% are at risk to the ALB (Nowak et al. 2007). Apparently no one has yet estimated the numbers of trees at risk to sudden oak death (SOD), goldspotted oak borer (GSOB), or polypagous shot hole borer (PSHB).

It is essential that USDA APHIS act more aggressively to prevent additional introductions of pests via wood packaging. (For a longer discussion of the wood packaging pathway, visit my previous blog posted on July 15th). In brief:
• APHIS & the Bureau of Customs and Border protection should penalize all importers whose wood packaging does not comply with decade-old 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
• APHIS should re-consider the advantages of requiring importers to switch to packaging made from materials other than wooden boards.
• The President’s Office of Management and Budget should allow APHIS to finalize regulations – proposed in 5 years ago! – that would apply the international standard’s treatment requirements to wood packaging used in trade between the US and Canada. (Canada has been ready to adopt this measure for several years.)

SOURCES
Berger, P. Executive Director, PPQ Science and Technology, Presentation to the Continental Dialogue on Non-Native Forest Insects and Diseases, November 3, 2014

Ciecko, L., K. Tenneson, J. Dilley, K. Wolf. 2012. Seattle’s Forest Ecosystem Values: Analysis of the Structure, Function, and Economic Benefits; August 2012; GREEN CITIES RESEARCH ALLIANCE; City of Seattle Urban Forest Stewardship Plan 2013.

City of Seattle Urban Forest Stewardship Plan 2013.

Colunga-Garcia, M., R.A. Haack, and A.O. Adelaja. 2009. Freight Transportation and the Potential for Invasions of Exotic Insects in Urban and Periurban Forests of the US. J. Econ. Entomol. 102(1): 237-246 (2009); and raw data for the study provided by the authors.

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

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

Harriger, K. 2014. Presentation to the Continental Dialogue on Non-Native Forest Insects and Diseases, November 3, 2014

Leung, B., M.R. Springborn, J.A. Turner, E.G. Brockerhoff. 2014. Pathway-level risk analysis: the net present value of an invasive species policy in the US. The Ecological Society of America. Frontiers of Ecology.org

Nowak, D.J., R.E. Hoehn III, D.E. Crane, J.C. Stevens, J. T. Walton. 2007. Assessing Urban Forest Effects and Values: San Francisco’s Urban Forest. USDA Forest Service. Northern Research Station. Resource Bulletin NRS-8.

 

posted by F.T. Campbell

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.