Weekly in-season Updates
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INFORMATION |
June 3, 2007 Talkin’ Cotton J.C. Banks Cotton planting is essentially complete in irrigated areas and is well underway in dryland areas. Most early planted cotton is up to a good stand, but not growing rapidly due to a lack of heat and sunshine. I have been observing a few fields with wet weather blight on leaves and some disease lesions on roots, but warm weather should turn the cotton around and it should grow out of the early problems. The cooler weather that slows cotton growth also favors growth of weeds. We are learning the value of a yellow preemergence herbicide, even when we are in a Roundup Ready program. The wet weather has not allowed timely spraying of Roundup and weeds are growing much faster than the cotton. One of our weed problems that is much worse this year is horseweed (also called mares tail). This weed can be managed when it is small, but when it gets over six inches tall it is difficult to kill. It is really difficult to kill in no-till conditions if it was not controlled prior to planting. The best control programs have involved phenoxy herbicides alone or tank mixed in early to mid April about one month prior to planting. At planting or soon after planting, a treatment of Roundup will usually control the small weeds before they get large enough to be difficult to control. Continued Roundup treatments in the summer should be as needed to the weeds when they are small. If the weeds, (especially horseweed) are over 6 inches tall, the maximum labeled rate of Roundup should be used. Be sure to condition the spray solution with ammonium sulfate prior to adding the Roundup and set spray boom height and pressure to obtain maximum deposition on the weeds. For morningglory control in irrigated areas, Staple has been effective, but application needs to be made after the water furrows are made to avoid moving an untreated layer of soil on top of a band of Staple.
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