Tuesday, July 5, 2011

Critical Time to Invest in Managing Cotton Crop


I'm checking in with growers at our field day.
Dan Munk stresses importance of plant monitoring.


Can we declare California cotton the comeback commodity of 2011? When global prices sagged and water became a precious commodity during the height of the drought, some started to write the obituary for the state's cotton industry.

With apologies to Mark Twain, the reports of cotton’s death have been greatly exaggerated. While local growers and pest control advisors attended our Cotton Pest Management Field day last week, the National Agricultural Statistic Services was reporting planted cotton acreage in California this year surged to 450,000 acres, up 47.1 percent from last year. Pima planted acreage rose 44.4 percent to 260,000 acres while acala acreage increased 52.2 percent to 190,000 acres.

Growers are investing a lot in cotton this season. With everyone talking about a short season because of the unseasonable weather this year (including the weird summer rainfall last week), these next five to six weeks will be critical for setting the cotton crop. To assist growers through this important period, our Field Day experts offered these tips and observations:

Dr. Pete Goodell, University of California Statewide Integrated Pest Management advisor, Kearney Ag Center: In many cases in the northern San Joaquin Valley, there is a pretty good set going on. Lygus is going to be the primary threat to setting the crop. There are three things growers should do:
1 – Ask what are the potential sources for lygus.
2 – If you have lygus in your field, be vigilant about monitoring the fields to ensure you can detect them and carefully evaluate whether the populations collected in your sweep net are actually a damaging population.
3 – If you need to treat the fields, rotate your materials to avoid insecticide resistance and start with softer materials first. These materials will protect as many beneficial insects as possible and help you avoid outbreaks of aphids or spider mites.

We are behind this year, but if we get a warm October without rain then we will be able to enjoy an extended season. But if the season ends at the normal time, then it’s going to be a short season, which translates into a short crop.  Right now is the time to invest in getting a good set going. Go out and look at your crop. Don’t panic. For those with alfalfa nearby, leave alfalfa strips wherever you can during your next two cuts this month to protect your cotton fields from lygus.

Dan Munk, Cotton Specialist, UC Cooperative Extension farm advisor in Fresno County: With talk about the late development of the crop, growers should be realistic and adjust their practices with the expectation of a lower yield, particularly pima, which requires a longer season. Growers should scale back some nutrient applications to reflect those lower yield expectations.

Fusarium race 4 is a very serious issue. (The disease will causes cotyledons and leaves in young plants to wilt and drop. Certain pima varieties are the most severely affected.) During the season, there is not a lot you can do about it. To manage it, growers need to first recognize they have a problem, identify where it is in the field and take steps to contain it. The best tool for dealing with Fusarium race 4 for next season is using varieties that have a high tolerance for the disease. In the past five to six weeks, I have seen significant plant die back and presence of the disease in Fresno County. Call a farm advisor for a field visit if you suspect any problems. More information about the disease is available from UC IPM.

Bob Hutmacher, UC Statewide cotton specialist: Fusarium race 4 has spread over the past seven or eight years. Growers in the southern part of the Valley have dealt with the disease the longest. More growers are becoming educated and aware about the disease. The problem is caused by soil inhabiting fungal organisms that can survive in the soil for years. It is a long-term management issue for growers as they consider options to contain its spread. They are learning how to identify the disease and select resistance varieties.


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