ZENECA AG PRODUCTS has successfully tested a new Touchdown non-selective herbicide in over-the-top applications on Roundup Ready soybeans, corn and cotton. Zeneca anticipates registration of new Touchdown for the 2001 growing season.

The current Touchdown 5 formulation has been widely used over Roundup Ready soybeans and for burndown weed control, according to Bill Beutke, brand manager at Zeneca. But the company never registered Touchdown 5 over Roundup Ready corn or cotton because it sometimes caused unacceptable levels of phytotoxicity on those Roundup Ready crops.

"The new Touchdown features an innovative glyphosate molecule optimized by a unique, corn-based, balanced adjuvant system called IQ Technology," Beutke said. "In trials conducted by Zeneca and universities across the United States, the new, patented Touchdown formulation has delivered outstanding non-selective weed control and excellent crop safety to Roundup Ready crops, including Roundup Ready corn and Roundup Ready cotton. In hundreds of trials we saw essentially no effect on the crops at all, even when the herbicide was applied at three times the normal rate."

In addition to Roundup Ready corn and cotton, Beutke said, the new Touchdown will be registered as a burndown application in more than 100 additional crops.

"We expect to have all the applications that were on the Touchdown 5 label, plus many more," he added.

The IQ Technology improves spray retention, herbicide uptake and translocation of the active ingredient throughout the weed, Beutke said. At the same time, it minimizes potential phytotoxicity to Roundup Ready crops because the glyphosate salt and adjuvants are very gentle to epidermal cells on leaf surfaces.

Touchdown controls more than 170 weeds, including tough-to-control species such as velvetleaf, cocklebur, waterhemp, giant ragweed, smartweed, ivyleaf morningglory, prickly sida, quackgrass, johnsongrass, bermudagrass, broadleaf signalgrass and foxtails.

A typical use rate for the new Touchdown in many situations will be 1 quart per acre.