Friday, July 27, 2012

Getting into the Practice of Monitoring Your Field Before Treating for Pests

I spend a lot of time on the road, traveling around the Valley to scout out cotton and alfalfa fields to check on pests and development of the plants.

Recently, it struck me to see some growers treating their cotton fields (which are adjacent to alfalfa) for lygus. In contrast, growers participating in our San Joaquin Sustainable Farming Project haven’t made any new treatments. Instead, they are monitoring their fields and waiting for the pest counts to reach the Integrated Pest Management threshold for treatment. I’m encouraged by this trend.

Lygus can still cause problems for cotton plants.
For years, University of California IPM specialists have advocated these practices. I remember Walt Bentley, a veteran UC IPM entomologist,  stressing to almond growers to forget the old practice of using the calendar as a treatment guide. Monitor your crop, keep track of pest counts and use that information to help you make a treatment decision. That message never gets old.

In fact, I’m finding lygus almost a non-factor in some fields. But it’s still important to keep an eye out for the pests. Small cotton bolls are still soft and susceptible to nymphs picking at them, resulting in the fruit dropping to the ground. My crystal ball predicts cut-out around the first weekend of August.
Cotton plants are nearing cutout in the Valley.
- Texas AgriLife Extension Service photo
Meanwhile, I’m finding a slight increase in aphids around the cotton fields. But the numbers don’t warrant treatment at the moment.

The plants are looking good. I’m seeing 80 percent fruit retention on the top of the plant and about 90 percent retention at the bottom – or first five fruiting branches. We should see some nice yields at harvest.
Things are quiet with alfalfa, as well. While there has been an increase in worm counts, it doesn’t warrant treatment for now. Growers have finished their fourth cutting and preparing for the next one soon.
Read more about these issues on the blog by Dr. Pete Goodell of UC IPM.

It was great meeting with growers and pest control advisors during our Cotton and Alfalfa Field Day in Los Banos on Tuesday. I want to thank our speakers Dr. Goodell, UCCE farm advisor Dan Munk and UC Davis alfalfa specialist Dan Putnam.

About Almonds: I want to share a recent chat with Walt Bentley about this year’s almond season. “The season is going very well. The disease pressure we’ve seen in the past is not being seen in the orchards we are monitoring. I’m not seeing near the issue of rust that we had. Much like last year, we’re not seeing very much spider mite problems. The pressure from mites has been low. The crop yields for nonpareils and the hard shell varieties have been excellent. Although we did start a little cooler and wetter than in the past, the main difference from last year is we’re experiencing what I call a normal year with hull split occurring in the early part of July. Last year we had hull split till about July 25, which was extremely late. I think that helped us in managing our navel orangeworm problem. Managing the diseases has been excellent.”

“Another big is now for growers from Fresno north is the management of preharvest irrigation to reduce the incidence of hull rot and harden the trees for proper shaking. Contact your local farm advisor, PCA or look to the Almond Doctor blog by UCCE Merced County farm advisor David Doll on dealing with preharvest irrigation practices.”

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