Growers of onions in California are expected to have a Section 18 clearance for use of Movento, considered an effective insecticide for control of thrips, very soon.

And another weapon for thrips control could be added to the industry arsenal as early as next year with clearance for Torac.

Those were among news elements that emerged in this year’s California Garlic and Onion Symposium held in Tulare.

The symposium opened with San Joaquin Valley onion and garlic producer Kevin Lehar, a member of the California Garlic and Onion Research Advisory Board, tracing the history of white rot and how that drove much of the industry from the Santa Clara and Salinas valleys and over the hills into the San Joaquin Valley.

White rot was an issue in 2012 as well, “really tough,” Lehar said. He is crop production manager for Woolf Enterprises, Huron, Calif.  And Lehar, an onion grower for 25 years, called last season “the worst onion maggot year” he has experienced.

Other speakers talked of high pressure last year from thrips, the most damaging insect pest of onions in California, which scars leaves, cuts yield and can carry iris yellow spot virus.

At the same time, speakers said, damage from garlic rust was down in 2012, but they warned that growers need to keep their guard up and be sure that existing treatments are working.

 

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Among the advisory board projects is joint sponsorship with the University of California of bee research on seed onion production to determine why there has been a decline in yields.

And Lehar laid out the protocol for avoiding the spread of white rot by using clean, disease free garlic seeds and onion transplants; sanitizing equipment before entering a field and reporting all fields with white rot infestations.

“We can’t do what was done 30 years ago,” he said. “We have to head this off at the pass.”

Lehar is hoping that problems of infestation can be dealt with through “spot treatment” without over-burdening growers.

Mary Ruth McDonald, with the University of Guelph in Ontario, Canada, talked of research on control of onion maggots and seed corn maggots. She said in-furrow applications of Capture and Force reduced damage. It was unclear if Movento had an effect. She said new registered seed treatments work well.

McDonald said Spinosad bait is formulated to attract flies. She said perhaps it could be used at the edge of fields to draw flies away from the main crop.