Ask your PCA:
What are you doing to control pests like worms, thrips and leafminers?

Issue Date: July 23, 2008

Ron Riddle

By Ron Riddle, AgRx, Santa Maria CAPCA member

We're in the heart of lettuce and celery season, but we work on broccoli and cauliflower year-round.

Quality is essential for the crops and I define that as a lack of insect scarring and diseases. Consumers want their produce to look appealing and our job is to keep the growing environment as pristine as possible.

We've been contending with thrip pressure in lettuce and celery this spring and summer. And, these days, when a pest flares up, we use pest-specific materials to target the problem.

How we approach our IPM programs always depends on what pests are present. We also have to keep in mind pests that may be present later. We're always looking to protect beneficials. We can't just focus on the immediate spray, but look to the impact as the crop matures.

This season we had lots of thrips, almost a nightmare in some places. And we also had quite a bit of cabbage looper in lettuce this spring.

We got on top of it, but now they're starting to rebound and so are some of the aphids we deal with. We had a particular early problem with foxglove aphid even with a preplant treatment.

Right now we're also starting to see leafminer emerge. That looks like it could be a real problem.

But, even as harvest gets close, most of the materials we use are fast acting and can be safely applied close to harvest. We're seeing an increased number of reduced-risk materials come onto the market.

One of the older materials we're using for downy mildew has a 14-day harvest interval. But that's becoming an exception. More materials these days can be applied only one or two days before harvest.

These new chemistries offer fast-acting control, are friendly to the environment and they're more pest specific. More than ever, I'm tailoring my recommendations to the specific pest problems.

Fall is probably the most difficult time for worms--loopers, beet army worm, corn ear worm, variegated cut worms. So, it's a time when we really have to focus on our IPM programs and in particular we have to stay on top of the increasing worm pressure.

This is a very busy time of year and it will stay that way until mid-October. We've got lots of crops in the ground and they grow really fast. That keeps me on my toes.

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