When it comes to Texas Panhandle cotton, seed choices booked now are the best defense against the worst cotton disease in the Southern High Plains, according to a researcher with Texas AgriLife Research.
Dr. Terry Wheeler, a cotton pathologist at Lubbock, said the fungus causing verticillium wilt has become the region's worst cotton profit-stealer.
“Many farmers buy their seed now for spring planting,” Wheeler said. “Planting varieties that yield well in the presence of verticillium wilt is the best way we know to minimize verticillium wilt losses. It's important to know which varieties are the most resistant, but that will still make good cotton.”
Wheeler said verticillium wilt is no newcomer to the High Plains, and cotton isn't the only crop it hits. It also affects melons, peanuts, peppers and ornamentals by clogging the plant's vascular system thus disrupting the plant's water flow.
The Texas High Plains typically boasts more than 3.3 million acres of cotton valued at more than $830 million. That's three times more than any other state, so anything affecting the crop is serious business, Wheeler said.
In past decades, the disease could be kept in check by planting popular varieties which had some resistance to the fungus.
“Starting around 2001 though, farmers changed from planting the partially resistant stripper varieties to planting picker varieties, because they made more consistently high cotton yields and the lint was of a higher quality,” Wheeler said. “Unfortunately, many of the picker varieties are much more susceptible to this disease.”
Wheeler said the problems didn't become obvious until 2004 when cool, wet conditions provided the perfect weather for the disease to flourish. Since then, the fungus has been the region's most yield-limiting disease regardless of the weather, though irrigated cotton fares the worst.
Over the past six years, Wheeler has been testing a combination of new breeding lines before they are released for sale, new varieties now available and some older varieties. All were planted in small plots located in six verticillium wilt-infested cotton fields with FiberMax 9180B2F, a standard recommended variety being planted in all six sites.
“New varieties or breeding lines that ranked higher in relative value after averaging over all sites than FiberMax 9180B2F included: the NexGen varieties; 3348B2RF, 2549B2RF, 4010 B2RF (will be available in 2011), 4111RF (will be available in 2011), 3410RF; Stoneville 4288B2F and FiberMax 9160B2F and 9170B2F.”
Aside from planting verticillium wilt-tolerant or partially resistant varieties, Wheeler said, planting appropriate seed densities of four seeds per foot of row, not overwatering, and using crop rotation with sorghum or corn when possible will also lessen damage from this disease.
For more information on the best verticillium wilt-resistant cotton varieties from Wheeler's study, see: http://lubbock.tamu.edu.