The 2009 cotton crop is looking good, but needs a rain, says J. C. Banks, Oklahoma State University Extension state cotton specialist.

"With the recent hot days, the Oklahoma cotton crop is off and running. The planting season was delayed by wet weather and started about May 10. Most of our crop was planted by May 25. We lost some cotton in isolated areas due to windstorms and hail, but losses this year are much less than normal.

"Cotton is now squaring in most areas and should be at first bloom approximately July 10. Moisture conditions vary across the region, but we need a good general rain as the plant begins to load. Now is the time to consider using plant growth regulators as the plant approaches first bloom.

"There are two scenarios that are commonly used in application of mepiquat based plant growth regulators. The first technique is usually used in dryland areas or areas that can be easily moisture-stressed, and it involves use of lower rates (4 to 8ounces of mepiquat or two ounces of Stance) at match head square. If the cotton continues to grow and is not stressed, another application about 10 days to 2 weeks later can be used.

"Another technique used in full irrigated areas involves using 8 ounces of mepiquat or 2 to 4 ounces of Stance at first bloom. This may be adequate, but under continued rapid growing conditions, another application may be needed. Plant growth regulators should never be applied on stressed cotton or cotton that will likely be stressed in the next week or 10 days. This application could increase fruit shed shortly following bloom. A good technique to determine how active the plant is growing is average internode spacing before bloom and the number of nodes from the lowest first position white flower to the top of the plant during blooming.

"Prior to bloom, if average internode spacing is less than 1.75 inches to 2 inches, an application is not needed. Following first bloom, the nodes above white flower should be above six or seven to justify application of PGRs,” Banks says.

"Our research has shown that growth regulators do not appreciably increase yield, but they decrease plant height and contribute to an earlier and less difficult harvest. In our short growing season with a chance of an early fall, this operation can easily be justified."

COTTON GROWTH TABLE

State of growth GDD* Days
Emergence 50-60 3-4
Pinhead square 425-500 25-45
First bloom 725-825 41-67
Open Boll 1575-1925 102-127
Defoliation 2150-2300 120-140



TALKIN' COTTON is produced by NTOK Cotton, a cotton industry partnership, which supports and encourages cotton production in the Rolling Plains of North Texas, Oklahoma and Kansas. For more information on the cotton scene, see okiecotton.org and ntokcotton.org. For comments or questions on Talkin' Cotton, contact eventerprise1@hughes.net.