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.