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Citrus thrips management programs developed for blueberries

The Issue

Blueberries are one of the newest crops grown in California, and are now planted on more than 5,000 acres statewide. Recently, however, blueberry fields have been under attack by a longtime California pest called citrus thrips. Feeding by thrips causes distortion, discoloration, stunting of new shoot growth, and damage to the development of fruiting wood that supports the next year’s crop. Due to the severity of the damage, one of the largest blueberry growers in the state reported that he was spraying pesticides more than 10 times per year to minimize crop losses.

What Has ANR Done?

The UC Statewide Integrated Pest Management Program provided funding for a team of UC researchers and cooperators to develop a program for citrus thrip management in blueberries. The team was led by UC IPM farm advisor David Haviland and included UC Riverside entomologist Joseph Morse and UC small farms advisor Manuel Jimenez. The team discovered the pest’s seasonal biology, developed monitoring programs, and evaluated differences in varietal susceptibility to damage and chemical controls.

The group also evaluated nonchemical controls such as the use of high-pressure water and fungi that can act as parasites of insects and kill or seriously disable them. These latter techniques were investigated as a way to delay resistance to the relatively few pesticides registered for blueberries that are being used repeatedly on some fields to combat citrus thrips.

The Payoff

Growers are now successfully managing citrus thrips in blueberries

As a result of UC research, blueberry producers have the basic tools they need to prevent thrips damage and crop losses, and they have begun to adopt those practices. John Ojala, an agronomist with the largest blueberry farm in the San Joaquin Valley, stated that this project has resulted in "an improvement in sustainable blueberry production for California." He estimated that, on their ranches alone, results of this project have conservatively increased the crop revenue of their company by more than $2.5 million each season.


Supporting Unit: Kern County

David Haviland, (661) 868-6215, dhaviland@ucdavis.edu