LUBBOCK–A crisis exemption allowing area grain sorghum producers to use Tilt fungicide to control sorghum leaf blight has been issued by the Texas Department of Agriculture.
The disease in sorghum fields across the Texas High Plains has been brought on by unusually wet and cool weather early in the growing season, said Dr. Harold Kaufman, associate professor and plant pathologist with the Texas Agricultural Extension Service here.
“Showers and cooler temperatures being predicted for the area will favor additional infection,” Kaufman said. “Protection of the youngest foliage, critical to grain filling, is very important. Heavy foliage infection before head emergence can cause yield losses of 50 percent. Heavy leaf infection after flowering will cause minimal yield loss.”
Use of the fungicide, with certain restrictions, was authorized to begin Monday, July 28, in only the following 45 counties:
Armstrong, Bailey, Borden, Briscoe, Carson, Castro, Cochran, Collingsworth, Crosby, Dallam, Dawson, Deaf Smith, Dickens, Donley, Floyd, Gaines, Garza, Gray, Hale, Hall, Hansford, Hartley, Hemphill, Hockley, Hutchinson, Kent, Lamb, Lipscomb, Lubbock, Lynn, Mitchell, Moore, Motley, Ochiltree, Oldham, Parmer, Potter, Randall, Roberts, Scurry, Sherman, Swisher, Terry, Wheeler and Yoakum.
Application of Tilt, manufactured by Novartis Corp., may begin when symptoms of sorghum leaf blight appear, TDA said. It may be applied at the rate of 2 to 4 fluid ounces per acre in a minimum of 15 gallons of water per acre when ground application is used. When aerial application is used, the fungicide should be applied at a rate 2 to 4 fluid ounces per acre in a minimum of 5 gallons of water per acre.
No more than 8 fluid ounces of Tilt per acre may be applied in the control of sorghum leaf blight. Tilt may not be applied within 21 days prior to harvest.
Application may be made only by certified applicators, by licensed applicators or by persons under the direct supervision of licensed applicators, TDA said. Applicators must have a copy of the crisis exemption label in their possession to be legal. Copies can be obtained from county extension agents or extension agents-IPM.
Kaufman cautioned that a crisis exemption is currently in effect for the use of Tilt to control sorghum ergot, another disease. He warned that no more than 12 fluid ounces of Tilt can be used per acre in one season to control both sorghum ergot and sorghum leaf blight.
By Aug. 12, TDA will submit to the U.S. Environmental Protection Agency an application for a specific exemption for the use of Tilt, said Donnie Dippel, assistant TDA commissioner for pesticide programs. This action will maintain the crisis exemption in effect until EPA renders a decision on the specific exemption application, he said.