SACRAMENTO – The California Department of Food and Agriculture (CDFA) and the United States Department of Agriculture (USDA) have completed an action plan outlining 2008 strategies in the ongoing project to eradicate the light brown apple moth (LBAM) from California’s Central Coast and Bay Area communities.
The light brown apple moth is native to Australia and is found in New Zealand, the United Kingdom and Hawaii. The range of host plants is broad with more than two-thousand plant species known to be susceptible to attack by this pest. It threatens California’s environment—including cypress, redwood and oak trees—by destroying, stunting or deforming young seedlings and damaging new growth in the forest canopy. The moth also feeds on host plants favored by a number of endangered species; spoils the appearance of ornamental plants; and injures citrus, grapes, and deciduous fruit tree crops.
A USDA study indicates that, if California becomes generally infested, the moth would cause between $160 million and $640 million in crop damage annually. Additionally, it would hinder export opportunities and interstate commerce due to quarantine restrictions. Already, Mexico and Canada have imposed export regulations on California because of the LBAM infestation.
The overall goal of the project is to eradicate the light brown apple moth from California. This task will likely take several years to accomplish using several treatment tools, some of which are available and in use now while others are under review or development.
The primary tool for eradication will be aerial treatment with LBAM moth pheromone, which will disrupt the pest’s mating cycle. Moth pheromone does not harm people, pets or plants. While conventional insecticides are designed to kill insects, pheromones are designed to distract or confuse them so that they cannot breed. In nature, the pheromone is released by the female moth to attract a mate. The “scent” is undetectable to humans and is highly specific to the light brown apple moth and several other closely related species, so it does not affect other kinds of insects or animals.
Aerial treatments are expected to begin June 1 in the infested areas of Monterey and Santa Cruz counties, with subsequent aerial treatments expected to begin August 1 in San Francisco, Daly City, Colma, Oakland, Piedmont, Emeryville, Albany, El Cerrito, El Sobrante, Tiburon and Belvedere. The treatments in these areas are designed to be reapplied at 30- to 90-day intervals while the moths are active.
In some of the areas designated for aerial treatment, the plan also calls for the release of tiny, stingerless wasps (trichogramma) that target the LBAM eggs. The native California wasps are 1/25th of an inch long, harmless to people and pets and they are widely used by home gardeners and organic or IPM growers. The wasps would be released in Spring 2008 and would be used in conjunction with aerial treatments – most likely in San Francisco, Santa Cruz County, and on the Monterey Peninsula. These wasps will not bother over-wintering monarch butterflies and they would not be released near threatened or endangered plants or butterflies and moths.
Smaller, more isolated infested areas would be treated using either pheromone-infused twist ties or a pheromone-based male moth attractant treatment applied to utility poles and street trees on public and private property. In each area, the infestation’s size and density, the availability of host plants, and other variables will be considered in determining the appropriate method. Twist ties have been used successfully in several areas over the past year, and additional applications are scheduled to begin over the next few weeks in Marin and San Mateo counties, with other areas to be announced in the coming weeks as the weather warms up and the moths become more active. Male attractant treatment may begin in Spring 2008.
In the event of detection of a heavy larval population, the action plan calls for handheld spraying of plants and trees with Bt (Bacillus thuringiensis) or Spinosad, both of which derive from naturally- occurring bacteria and are approved for use on organic crops.
The action plan also provides for consultation with the Department of Pesticide Regulation (DPR) concerning pesticide use, and contains provisions for sharing information with the California Office of Environmental Health Hazard Assessment (OEHHA) and other agencies for their use in educating physicians in the treatment areas, protecting threatened and endangered species and sensitive sites, and obtaining all required permits. OEHHA will team with other public health organizations to develop and oversee a program for the reporting, tracking and scientific evaluation of reported illness incidents. To date, collaboration between OEHHA and DPR has resulted in a consensus statement concluding that illnesses reported last year in Santa Cruz and Monterey counties were not likely to have been caused by pheromone treatments there.
The action plan has been developed in consultation with representatives of the LBAM Technical Working Group as a guide to the major elements and strategies of the eradication program. Specific actions will be guided by this plan, which could be modified due to new moth detections and trapping results, as well as operational constraints such as funding and the availability of treatment materials.
Since its detection in February 2007, the Light Brown Apple Moth has been found throughout the central coast region in the counties of Monterey, Santa Cruz, Santa Clara, San Mateo, Contra Costa, Marin, San Francisco, Alameda and Solano. CDFA and the USDA continue work on treatment plans for communities within these counties. Small, isolated infestations detected last year in Los Angeles and Napa counties have already been eradicated. Twist ties were utilized in both counties.
Additional information on the action plan is available at: www.cdfa.ca.gov/lbam
California Department of Food and Agriculture Office of Public Affairs
1220 N St., Ste. 214, Sacramento, CA 95814