Pest pressure mixed in vegetable crops

Pest pressure in vegetables in the southern San Joaquin Valley has been relatively light as the 2007 crop gets under way.

“We’ve had some aphid activity on potatoes and peppers,” says Joe Nunez, Kern County farm advisor. “I’d say the cold winter has probably delayed pest pressure a bit. We’re seeing some cucumber mosaic virus in peppers in the Mettler area. It’s hitting some growers pretty hard, and others are not really affected that much.”

In spite of the below average winter rainfall, Nunez says he doesn’t anticipate growers will have too much of a problem with water – at least not this year.

“Growers have definitely been allocated less water than last year, but they’ll probably make up for it with groundwater,” he says. “But, if this situation continues, water could be an issue next year.”

Traversing northward along Highway 99, pests are a bit more of an issue.

“In the northern San Joaquin Valley, we are currently experiencing heavy thrips infestations in many vegetable and herb crops,” says Jan Mickler, Merced County farm advisor. “The impact, if any, on produce marketability is unknown at this time, or is complicated by additional factors affecting the production of the crop.”

Other pests are also reaching treatment thresholds, according to Mickler.

“Aphid pressure is also high. For certain crops and crop growth stages, these pests are being controlled with insecticides. Early instars of the beet armyworm were observed last week in a number of specialty crops growing east of the San Joaquin River. Unusually low moth numbers have been recorded from bucket traps this year, but this may be a location effect.”

Moving toward the Salinas Valley, it’s a different scenario. A dry, cold winter could be a factor in fewer insects overwintering and moving out of the adjacent foothills as temperatures warm and what little vegetation exists dries down.

“Pest pressure in this area has been relatively low so far this year,” says Bob Fowler, PCA with Integrated Crop Management Consultants, Inc., at Greenfield. “We’ve had scattered activity of red lettuce aphid and green peach aphid. Thrips and lygus are just starting to move around a bit, but that’s been fairly light also.”

That’s good news for Salinas Valley growers who are still reeling from the aftermath of the E.coli situation that occurred in spinach last year.

“Our biggest concern and most time-consuming task when it comes to production right now is the food safety aspect,” Fowler says. “I’m driving all over the place handing out 600 page-plus Material Safety Data books to my growers to make sure they know what they have to do.

“If they get audited, they need to show that they’re in compliance and be able to come up with the documentation to prove it. It’s a blessing we’re not having to battle a lot of pest pressure right now, because we’re extremely busy on other fronts.”

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