Monday, August 15, 2011

Valley Cotton Growers Are Preparing for Last Irrigation

After another weird weather year, we’re finally heading down the backstretch of the cotton-growing season.

Growers are counting the days before they cut off irrigation and get their crops ready for harvest. Typically, the last irrigation comes between Aug. 20 and Aug. 25. Before you know it, the fields will be alive with the click-clacking sounds of the harvesters working the fields.

Right now, I’m still seeing lygus treatment applied around the around the Valley. Growers are concerned about retention and plant stands.

In the acala varieties, there should be five to six nodes above white flower. With water cut-off around the corner, growers expect that 20 percent of the crop above white flower will make it by harvest time. Growers should be cautious about scheduling any late-season treatment for lygus. It may not be worth the extra expense. The University of California Statewide Integrated Pest Management program offers a publication discussing nodes above white flower measurements for determining when to stop monitoring for lygus.
I want to re-emphasize the importance of going into the fields to inspect plant development, monitor pests and determine when to schedule the last irrigation.

Overall, the cotton plants I am seeing have up to 73 to 76 percent retention. Lygus pressure has been higher this season, but treatment has been effective to control potential plant damage.

I’m finding late-season mite damage, which was virtually non-existent in the past couple of years. These pests are migrating from almond orchards being harvested or dusty roads that are not being sprayed with water to control dust. If there are mite problems, growers should consider adding some miticides to their other treatment. Aphid issues are occurring in areas near harvested tomato and cantaloupe fields.

Field Day Alert: Our next cotton field day will be coming up in early September. University of California extension advisors and IPM specialists will be among the experts discussing defoliation and other harvest-related topics. I will pass along more information after we work out the final details.

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