The star-studded list of invasive species facing California resembles a Hollywood ‘Who’s Who’ list for a red carpet movie premiere: the European grapevine moth, fruit flies, Asian citrus psyllid, and the light brown apple moth.
Today, about 1,700 invasive species threaten California, according to a list compiled by the advisory committee to the Invasive Species Council of California (ISCC). The ISCC is a California state agency council working toward complementary, cost-efficient, environmentally sound, and effective state activities aimed at invasive species.
“California is inundated with invasive pests,” said Robert Leavitt, ISCC executive director and director of Plant Health and Pest Prevention Services with the California Department of Food and Agriculture (CDFA), Sacramento, Calif.
Leavitt says planning, reporting, plus local, state, and national coordination are critical to invasive pest control.
Leavitt discussed invasive species during the 36th annual California Association of Pest Control Advisers (CAPCA) Conference in Anaheim, Calif., in October. More than 1,100 pest control advisers and related industry members attended the event.
Invasive species challenge pest control advisers, farmers, and government, education, and industry leaders. Leavitt outlined the ongoing combat against several major invasive species.
European grapevine moth
The CDFA, University of California, USDA, PCAs and others found themselves at war over the last year against the European grapevine moth (EGVM), Lobesia botrana. The first U.S. find of the insect occurred last fall in the Oakville area in Napa County’s wine grape country.
The moths then spread into other counties. Second and third-generation larvae cause severe damage to grapes. The battle this year focused on utilizing integrated pest management (IPM) practices in vineyards.
“The highest priority was given to grape growers with vineyards that lie within 400 meters of a confirmed trapping of EGVM,” Leavitt said.
Treatment coordinators (all licensed PCAs) served as grower liaisons in several counties to manage and monitor grower strategies. USDA’s Natural Resources Conservation Services in California provided $1 million to assist grape growers with IPM practices including “softer” chemical use. NRCS funds from the agency’s environmental quality incentives program helped eligible farmers cover about half the costs of IPM materials.
Asian citrus psyllid
Leavitt discussed the Asian citrus psyllid (ACP), an insect which vectors Huanglongbing disease (HLB), or citrus greening. The insect has the California citrus industry sleeping with one eye open.
“The psyllid itself is not a particularly (bad) pest but it can carry HLB, one of, if not the worst, citrus diseases in the world,” Leavitt said. “This disease is particularly a threat for the California citrus industry since most of the crop is sold for the fresh market.”
The ACP, Diaphorina citri, is an aphid-like insect that feeds on citrus tree flush in the spring and fall. HLB has impacted every major citrus-growing area in the world except the California-Arizona-Texas area. Every citrus tree infected with HLB eventually dies.
The ACP was first trapped in California’s San Diego County in August 2008 with later finds in Imperial, Los Angeles, and Orange counties. The psyllid was found in Arizona in October 2009. So far California and Arizona are HLB-free.
“When we first found the psyllid (in California), the citrus industry was quite concerned the psyllid would quickly spread into the major citrus belts in northern San Diego County, Ventura County, and from Bakersfield through Fresno,” Leavitt said.
“We’ve been able to keep the psyllid down and the disease out of California for two years. We are predicting we can do it for several more years.”
About 16,000 square miles in Southern California are under quarantine for the ACP, mostly citrus trees in urban areas managed by the CDFA.
HLB deforms citrus, turns it bitter, and quickly makes the crop unmarketable. The disease has devastated the Florida citrus industry, the nation’s largest citrus producer.
Effective Jan. 1, 2012, Leavitt says California citrus nurseries will be required to grow mother trees and increase plants under screen to keep new plantings disease free.
Leavitt says about 63,000 square miles of California were under active quarantines this year for EGVM, ACP, Karnal bunt, melon fruit fly, oriental fruit fly, LBAM, and the Phytophthora ramorum pathogen which causes sudden oak death disease.
Melon fruit fly
Control efforts for the melon fruit fly are centered in the Mettler area south of Bakersfield in Kern County. The infested area has kill traps on almost 200 square miles.
“We believe we’ve caught and killed all of the (melon) fruit flies in that infestation,” Leavitt said.
Light brown apple moth
Leavitt says populations of light brown apple moth continue to grow. Due to public concern, pheromone twist ties and dispensers have replaced aerial pheromone applications.
Sterile LBAM moths reared in the Watsonville area will likely be released late this winter and early next spring in the Long Beach area. Sterile moth confusion technology is designed for long-term LBAM control.
“Prevention is the first, cheapest, and most effective method,” Leavitt told the PCAs. “The earlier an invasive pest is found — then the cheaper, more effective, and more environmental friendly the response will be. If we find the pest early enough we can eradicate it so it doesn’t spread across the state.”
Leavitt asked PCAs to proactively be involved in invasive pest control by immediately reporting new pest finds, being informed on pest situations, staying current on pest management methods and approaches, conducting outreach on keeping pests out of California, and involvement in issues which impact California agriculture.
A.G. Kawamura, secretary, California Department of Food and Agriculture (CDFA), also spoke to the PCAs on invasive species. The secretary serves as the ISCC chair.
Secretary Kawamura says over the years the CDFA has learned better ways to tackle invasive species in the wake of public concerns over treatment methods, including more ground-based treatments versus aerial applications.
The agency has also learned to better pre-plan strategies against threatening pests, a lesson learned after rulings by judges in the LBAM issue which suggested the insect had not created enough damage to warrant an emergency effort so eradication should be stopped.
The CDFA’s new route is to create early programmatic, comprehensive environmental impact reports on insects.
“We used about $500,000 from a block grant from the specialty crop arena to ramp up environmental impact reports so we will have them in hand (early),” Kawamura said. “This is an import step forward for all of us.”
More groups, including the environmental community, now understand that invasive species are major threats to endangered species, habitat, and open landscapes.
Kawamura says agriculture has changed its pest control mentality; from killing every bug in the field during the 20th century to better tools available in the 21st century for more selective bug termination.
“We should be activists to close down the invasive species’ open door and close the gate,” Kawamura said. “We should put pressure on the president on down to talk about customs and border protection and homeland security to get them engaged with USDA-APHIS to create a layer of protection.”