PCAs Tackle Leafminer, Other Pests

Coastal celery and lettuce growers were preparing to treat leafminer pressures at thinning, amid heavier than normal pressures in second crop lettuce and celery.

“It’s been pretty heavy this year but it’s somewhat expected when you have a second crop of lettuce in back of lettuce, broccoli or cauliflower,” said Salinas area PCA Gene Spencer. “You’ve got a couple overlapping generations and it hits that young lettuce and causes problems.”

Leafminer is worse than usual in Spencer’s organic celery fields, he said, a crop where few controls exist.

“On organic celery we usually try to keep the crop a little on the dry side, withhold water, and if you need to spray come in with liquid pyrethrum,” Spencer said.

Spencer said he continues to be challenged by septoria blight in celery and cabbage aphid in cauliflower. “Cabbage aphid on cauliflower is up more this year than last, especially on organic cauliflower. Last year we had 20- to 30-percetn infestation, this year we are seeing 60-percetn infestation on organic cauliflower.”

Meanwhile, worm pressures, unseasonably light throughout the coastal vegetable season, were being treated in desert lettuce crops with standard treatments.

John Palumbo, research entomologist with the University of Arizona. Yuma Ag Center, said Yuma and Imperial desert growers were dealing with typical cabbage looper and beet armyworm pressures.

“So far worms are about what you would usually expect,” he said. “In 2003 we had real warm temperatures all through September which made for really heavy worm pressures all the way through October. So far, this year, it’s what we’d expect. We’re seeing plenty of cabbage looper eggs on cantaloupe and egg masses on transplants.”

Whitefly pressures have been light in comparison to heavy pressures this time last year, he said.

Palumbo said a thunderstorm the first week of September knocked down some pest populations providing a window of relief.

“We visibly noticed on cantaloupes that had some cabbage loopers starting to build that it had a big impact on them,” Palumbo said. “They’ll be back of course but it did have an impact.”

Damage to crops from the storm was reportedly light.

Flea beetles have also been active and growers were treating that sporadic problem at stand establishment largely with pyrethroid chemigation through. Some aerial treatments were being applied as well to get added control of other key pests.

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