Rice growers who rely on an early-season aerial application for control of annual grasses have a new option for the 2004 season.

Clincher SF herbicide can be tank-mixed with residual grass herbicides such as Command, Facet or Prowl for control of one- to three-leaf annual grasses that compete with young rice.

Clincher SF, a postemergence grass herbicide containing the active ingredient cyhalofop-butyl, controls a wide spectrum of annual and seedling perennial grasses, such as barnyardgrass (including propanil- and quinclorac-resistant biotypes), sprangletop, broadleaf signalgrass, knotgrass and fall panicum. EPA has categorized cyhalofop-butyl as a reduced-risk pesticide.

“Best results from a tank mix of Clincher and residual herbicides will come from aerial application within the first seven to 21 days after planting, depending on soil moisture and environmental conditions,” said Larry Walton, customer agronomist for Dow AgroSciences. “The key is to make sure the annual grass weeds are no larger than the three-leaf stage.

“It's also important to remember that although Clincher is effective against the target grasses, it has no pre-emergence activity. Any residual weed control will be provided by the tank-mix partner.”

For optimum results, use Clincher SF herbicide at a rate of 10 to 13.5 ounces per acre in the tank mix, along with the recommended rate of the residual herbicide. Add 1 quart per acre of crop oil concentrate with the tank mix. Spray volume should be no less than 10 gallons of water per acre.

“Thorough coverage, good soil moisture and actively growing grass weeds are the keys to success with this application,” Walton said. “The higher spray volume is necessary to obtain proper coverage of the young grass weeds. And the fields should be muddy, either partially or fully drained at application following at least a half-inch of rain or an irrigation flush.

“Ground equipment should not be used for this application. The rule of thumb is that the field should be too wet for a ground rig or to walk through.”

Before planning an aerial application of Clincher SF herbicide with Command, make sure that Command can be legally applied with an airplane in your state, county or parish.

While Clincher SF has excellent crop safety when used alone, the safety of the early-season aerial application is limited by the crop safety of the tank-mix partner. Growers and applicators should always follow low drift and application buffer zone requirements and use directions for the most restrictive of the tank mix products.