Updated: Citrus psyllid tops list of pest concerns

Issue Date: July 24, 2013
By Steve Adler
Justin Boyajian, a California Department of Food and Agriculture technician from Fresno, hooks a yellow sticky trap high in a navel orange tree as part of an intensive trapping effort following detection of more Asian citrus psyllids in Tulare County.
Photo/Cecilia Parsons
CDFA agricultural technician Justin Boyajian checks a trap in a Tulare County citrus grove as crews intensify their search for Asian citrus psyllids.
Photo/Cecilia Parsons

Update July 30: State and federal officials announced plans today for a 178 square-mile quarantine zone in Tulare County, affecting movement of citrus fruit and nursery plants. The area affected by the quarantine encompasses five miles around an area south of Porterville, where six Asian citrus psyllids were trapped in late June. Authorities described plans for the quarantine to hundreds of farmers and other representatives of the citrus business, who gathered in Tulare. A key restriction will require that citrus leaving the quarantine area be free of vegetative material and stems on which the pest can thrive. The quarantine will be finalized in coming days. Read more in the Aug. 7 issue of Ag Alert.

Hold orders on the movement of citrus nursery plants and fruit have been put into effect in Tulare County, near where six Asian citrus psyllids were discovered in late June.

According to Steve Lyle of the California Department of Food and Agriculture, the hold orders were put into place to stop the potential spread of the psyllid to other areas within citrus-rich Tulare County.

"We are introducing hold orders for retail establishments and packinghouses to control the movement of plants within a radius of five miles from the find sites," Lyle said. "We are notifying the affected parties that they cannot move citrus plants out of the hold-order areas. They can move fruit if it is free of stems and leaves."

No further restrictions have been put in place, but could be, Lyle said.

"With respect to quarantine, we are still working on that with the U.S. Department of Agriculture and the county agricultural commissioner. These things move carefully and we are continuing to do that work," he said.

Following the positive identification of the six psyllids in mid-July, CDFA and the county agricultural commissioner's office saturated the area with hundreds of additional traps. The traps have been checked daily and no additional pests had been trapped, Lyle said Monday.

Asian citrus psyllids generally don't harm the fruit, but they can carry the plant disease huanglongbing, which kills citrus trees and for which there is no known cure. A diseased tree will decline in health, producing bitter, misshapen fruit until it dies. To date, HLB has been detected in California on just one residential property in the Hacienda Heights neighborhood of Los Angeles.

Tulare County Agricultural Commissioner Marilyn Kinoshita said her staff, along with CDFA and University of California researchers, have been meeting with pest control advisors and treatment coordinators in Tulare, Fresno and Kern counties, to formulate actions to prevent the spread or establishment of the psyllid in the region.

"We had conference calls and a meeting with pest control advisors and our treatment coordinators for Fresno, Tulare and Kern counties. We are working as a group, because at any moment Fresno County or Kern County could experience the same thing," she said.

Kinoshita said growers and their farm managers in the three counties are well prepared to put into effect any treatment requirements needed for eradication.

"The treatment coordinators will contact the growers and farm managers to treat within a certain time frame, because any time you are doing something as a group, the eradication efforts are magnified," she said.

The Asian citrus psyllid was first detected in California in 2008 and is known to exist in Ventura, San Diego, Imperial, Orange, Santa Barbara, Los Angeles, San Bernardino and Riverside counties.

In addition to the Asian citrus psyllid situation, government pest fighters are dealing with several other exotic pest finds in California.

  • Peach fruit fly: Between June 14 and July 11, three male flies were detected in the cities of Chino and Chino Hills in San Bernardino County. This invasive species is native to Southeast Asia and India, and is a significant pest of a wide variety of fruits and vegetables. The finds triggered an eradication project using an attractant to lure and kill male files.
    One peach fruit fly was trapped in the city of Fairfield in Solano County on July 3. Additional traps placed in the area have not yet found more flies.
  • Oriental fruit fly: Four male flies were detected in the city of Anaheim in Orange County between May 9 and July 8. This is another highly invasive fruit fly, native to Southeast Asia and India, that feeds on a wide variety of fruits and vegetables. An eradication project is underway. A separate eradication project is underway elsewhere in Orange County, in response to discovery of three male Oriental fruit flies in Santa Ana. A third eradication project began last week in Los Angeles County, where four male Oriental fruit flies were detected in the cities of Cerritos and Artesia.
    Additional trapping is underway in two other areas where single, male flies were found: in the Los Angeles County city of Glendale, where the fly was trapped in mid-June, and the Orange County city of Placentia, where a fly was discovered last week.
  • Guava fruit fly: This is another invasive fly that feeds on a wide variety of fruits and vegetables. An eradication program using the male-attractant technique has begun in San Jose, where three guava fruit flies were trapped earlier this month. One male guava fruit fly was trapped in the Santa Clara County city of Cupertino last week, and a single fly turned up in mid-June in the Orange County city of Garden Grove; additional trapping has been conducted in both areas.
  • Light brown apple moth: An infestation of the moth has been confirmed in the Oceanside area of San Diego County. Detections have resulted in establishment of an 18-square-mile regulated area. Treatment for LBAM began in Oceanside Monday, following a public meeting last week to discuss treatments with growers, local residents and other interested parties. Mating disruption will be used in the form of pheromone twist ties.
  • European grapevine moth: Between March 29 and July 2, 40 European grapevine moths were trapped in Napa County. Treatments with Bt, fruit removal and mating disruption are underway to combat the grapevine pest.
  • Gypsy moth: On July 8 and July 9, two male gypsy moths were trapped in the Butte County community of Magalia. Molecular diagnostics confirmed they were European gypsy moths, a type of the forest pest that is common in the northeastern U.S. Additional traps were placed and have not yet trapped any more moths.

(Steve Adler is associate editor of Ag Alert. He may be contacted at sadler@cfbf.com.)

Permission for use is granted, however, credit must be made to the California Farm Bureau Federation when reprinting this item.