United States Department of Agriculture
Marketing and Regulatory Programs
Animal and Plant Health Inspection Service
reatment Program for Light Brown Apple Moth in Santa Cruz and Northern Monterey Counties, California
Treatment Program for Light Brown Apple Moth in Santa Cruz and Northern Monterey Counties, California
Director, Emergency Management
Emergency and Domestic Programs
Plant Protection and Quarantine
Animal Plant Health Inspection Service
U.S. Department of Agriculture
4700 River Rd. Unit 134
Riverdale, MD 20737
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Table of Contents
I. Introduction 1
A. Biology of Light Brown Apple Moth 1
B. History of Infestation in California 1
C. Purpose and Need 3
D. Affected Environment 4
II. Alternatives 7
A. No Action 7
B. Treatment Alternative 7
III. Environmental Impacts 9
A. No Action 9
B. Treatment Alternative 9
C. Cumulative Effects 12
D. Threatened and Endangered Species 13
E. Other Considerations 14
IV. Listing of Agencies and Persons Consulted 16
V. References 17
Appendix A: Light Brown Apple Moth Host List
Appendix B: Proposed Treatment Area
Appendix C: Ecological Risk Assessment
A. Biology of Light Brown Apple Moth
The light brown apple moth (LBAM) (Epiphyas postvittana) is native to Australia where it is an economically important pest on many fruit crops. The LBAM attacks a wide variety of plants. A recently compiled LBAM host list (USDA, 2007a; see appendix A) indicates there are at least 2,042 different plants that are reported to be hosts of LBAM. The list includes numerous native plants, forest species, and over 200 agronomically important crops (appendix A). In addition to Australia, LBAM has also been found in New Zealand, New Caledonia, Hawaii, and the British Isles.
The moth lays eggs in overlapping masses, preferably on leaves, but also on fruit and stems of the host plant. The larvae hatch and then pass through six stages of growth reaching approximately 18 millimeters (mm) in length before pupation. Young larvae are pale yellow while the mature larvae are pale green (Mo, 2006). Larvae will feed on leaves and fruit from susceptible host plants. In all stages, larvae will construct silken shelters at the feeding site which is where pupation occurs. Both female and male adults are light brown in color. The females are distinguished by a dark spot in the center of the front wings when folded. The number of LBAM generations produced in a growing season varies from one to over four, depending on environmental conditions (Danthanarayana, 1983; Mo et al., 2006), although the climate in California may allow four to five generations to occur in the infested counties. In cases where multiple generations occur in a season, the population can build to economically important thresholds quickly.
The California Department of Food and Agriculture (CDFA) was notified on February 6, 2007, that LBAM had been found in 2006 and subsequently identified by an Australian expert from a site near Berkeley in Alameda County, California. This initiated CDFA trapping which resulted in the finding of additional moths beginning February 27. On March 16, 2007, the Agriculture Research Service Systematic Entomology Laboratory in Washington, DC confirmed that the original find was positive for LBAM. In response, pheromone-baited traps were placed in Alameda and Contra Costa Counties to determine where LBAM populations existed in the area. On April 20, 2007, CDFA issued a quarantine of at least 182-square miles in Alameda, Contra Costa, San Francisco, Marin, and Santa Clara Counties.
The United States Department of Agriculture (USDA), Animal and Plant Health Inspection Service (APHIS) issued a Federal quarantine order on May 2, 2007, requiring trapping, inspection, and certification of all nursery stock and host commodities from quarantine areas. The original quarantine area consisted of only eight counties. Today the quarantine area includes the following counties: Alameda, Contra Costa, Los Angeles, Marin, Monterey, Napa, San Francisco, San Mateo, Santa Clara, Santa Cruz, and Solano. The quarantine area will continue to expand if LBAM is identified in new counties.
Since March 2007, more than 41,000 traps have been placed throughout California and approximately 8,000 moths have been confirmed as LBAM (CDFA, 2007a). Most of the captures (99 percent), however, are from traps located in two specific geographical areas. The first area, representing 87 percent of all LBAM captures, encompasses southern Santa Cruz and northern Monterey Counties. The second area, which represents approximately 12 percent of captures, includes contiguous portions of northwest Alameda, western Contra Costa, and northern San Francisco Counties. The remaining 1 percent came from mostly single trap captures in Los Angeles, Marin, Napa, San Mateo, Santa Clara, and Solano Counties.
In May, 2007, APHIS convened a group of international scientific experts (the Technical Working Group or TWG) to provide recommendations on short- and long-term plans to contain, control, and eradicate LBAM in California. The TWG toured the infested region on May 16 and concluded with a 2-day meeting in San Jose, California. They evaluated the distribution of LBAM and suggested treatment options for isolated areas and the main population areas. The recommendation of TWG was to prevent LBAM from spreading by first containing and eradicating LBAM from the outer edges of its range, and then eliminating the core population centers.
CDFA and APHIS started treatment of isolated populations in June 2007. To date, isolated populations in Napa, Oakley, Danville, Dublin, Sherman Oaks, San Jose, and Vallejo have been treated with pheromone twist ties, a mating disruption technique. The areas of Napa and Oakley also were treated with three ground applications of Bacillus thuringiensis kurstaki (Btk), a biologically based pesticide that is effective against early larval stages of most lepidopterans prior to the use of the pheromone twist ties.
Trapping results indicated that populations in the area from the Salinas River south to the Monterey Peninsula were growing and, if left unchecked, could become an extension of the more heavily populated area around Soquel and southern Santa Cruz. In an effort to constrict this growth, the area from Marina and Seaside southward to and including most of the Monterey Peninsula was aerially treated on four consecutive nights beginning on the night of September 9 and ending in the early morning hours of September 13, 2007, with microencapsulated pheromone to disrupt LBAM mating. The total treatment area was approximately 36,500 acres. A second treatment of this area is anticipated after 30 days (the effective life of the microencapsulated pheromone once it has been applied). This treatment is currently scheduled to begin on or about October 9. Pheromone traps are in place and will remain throughout the treatment period and beyond to measure LBAM populations. This information will be used to evaluate the effectiveness of the treatments and for determining what additional treatments will be made to complete eradication efforts in this area.