Citrus thrips

California Growers Needed for Thrips Study

Len WilcoxCalifornia Corner, Pests

Citrus thrips
(Photo by Joseph Morse, University of California, Riverside,

Researchers from the University of California’s Kearney Agricultural Research and Extension Center are asking for help from industry members as they investigate citrus thrips.

Thrips are a serious headache for citrus growers. They cause issues in all varieties of citrus, particularly in the San Joaquin Valley. Additionally, the pest has been known to rapidly develop resistance to management materials.

Growers and pest control advisors are being asked to provide field location and contact information in an effort to monitor insecticide resistance.

“Using the thrips that we collect from citrus growers’ orchards, we’re going to map for resistance. Although citrus thrips do disperse considerably, the resistance issue seems localized,” said Sandipa Gautam, assistant research entomologist at Kearney Agricultural Research and Extension Center. “We need as many growers as we can to participate so that we get a better understanding. The more populations, the better.”

Researchers are asking for assistance from industry members in the citrus-growing regions of Kings, Fresno, Kern, Tulare and Madera counties. Growers using spinetoram to control citrus thrips who are noticing a decline in efficacy are encouraged to contact Gautam. “If they are seeing treatment failures or high thrips populations this year compared to earlier years, we can go out in the field, collect the thrips from their orchards and bring them back to the lab to monitor for resistance,” Gautam said.

Populations of citrus thrips with a low resistance to spinetoram can often still be controlled with the material. Thrips populations with medium to high resistance can render applications essentially useless. Getting a better understanding of resistance will assist with developing alternative management approaches and methods for delaying resistance development.

“It is applied research, and we’re going to come back to communicate the results to growers. Also, in the following years we will continue monitoring,” said Gautam. “We want to do this over the years to see how resistance is developing over time and see if it is dispersing or not.”

To assist the research team, contact Gautam at or 559-646-6500.

Source: AgNet West

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