ZENECA AG Products is hoping its newly reformulated glyphosate herbicide will be granted full registration by the Environmental Protection Agency in time for the 2001 growing season.
The company's new glyphosate formulation will be known as Touchdown instead of Touchdown 5. Previously, Touchdown 5 was formulated with trimesium salt. The Touchdown product awaiting EPA approval uses a newly patented salt formulation which is not yet being publicized.
Another difference between the two Touchdown herbicide formulations is the amount of active ingredient per pound of product. Touchdown 5 was a 5-pound active ingredient formulation and the new Touchdown is a 3-pound acid equivalent (ae) formulation. What this means, the company says, is ease of use for those growers who switch to the new Touchdown from their regular glyphosate herbicide because they can use the same rates per acre.
"Upon registration, new Touchdown can be applied over Roundup Ready corn, cotton or soybeans with no significant crop response. It can also be used in all burndown applications," Zeneca says. "The balanced adjuvant delivery system integrates technically advanced ingredients that improve spray delivery and spray retention on leaf surfaces and help overcome antagonism from bad ions, including calcium and magnesium, in spray water or on leaf surfaces."
Mississippi cotton specialist Charles Ed Snipes, who is testing the newly reformulated Touchdown herbicide at the Delta Research and Extension Center in Stoneville, Miss., says he has seen no visible injury to Roundup Ready crops treated with the new Touchdown product.
In Snipes' tolerance trials of the new Touchdown, he has applied the product at rates of 1 quart of product to two-leaf cotton, 1 quart of product to four-leaf cotton, and 1 quart of product to two-leaf cotton followed by another 1-quart application when the cotton reaches the four-leaf stage.
"There appears to be no real difference between the new Touchdown and Roundup. They have exhibited the same level of weed control and crop tolerance in our field studies," Snipes says. "We won't know if there are any fruiting differences between the two compounds until we map our test plots later this year."
Dan Poston, assistant weed scientist at the Delta Research and Extension Center in Stoneville, Miss., says he has seen comparable results in his tests of the new Touchdown product applied in a Roundup Ready soybean system.
"With the old formulation, we often saw a small amount of crop injury. The new formulation of Touchdown, though, doesn't even have any leaf injury. From that perspective, there seems to be an advantage," says Poston.
Zeneca says it expects to sell completely out of the old Touchdown 5 product before the new reformulated Touchdown is offered to growers. According to Zeneca, the company hasn't yet put a price tag on the new Touchdown formulation, but says it should be comparable to Roundup Ultra and the other generic glyphosate formulations.