Monsanto is introducing new Degree Xtra herbicide, a soil temperature-activated formulation of acetochlor premixed with atrazine that extends the weed control window and maximizes safety to corn seedlings.
Acetochlor is the same active ingredient found in Harness and Harness Xtra brands.
Degree Xtra is unique, because it features patented encapsulation technology that releases increasing amounts of acetochlor as soil temperature rises above 50 degrees Fahrenheit. Below that temperature, no acetochlor is released. The atrazine in the mix is not encapsulated, so it provides contact and residual weed control immediately after application.
"The soil temperature-activation technology in Degree Xtra makes it an ideal choice for early pre-plant applications or for growers looking for maximum late season residual and crop safety," says Bart Baudler, Monsanto market manager.
Degree Xtra has received Environmental Protection Agency registration and will be available in limited quantities in 2000.
Tests have shown that the soil temperature-activation mechanism in Degree Xtra extends its residual activity longer than competitive products, including Bicep II Magnum, FulTime, Leadoff and guardsman, says Baudler.
The patented encapsulation technology enhances crop safety, says Rick Cole, corn herbicides technical manager for Monsanto.
"We have designed the capsule to release the safener faster than the herbicide, and thus reach the corn seedling first," says Cole. "You also aren't putting down a full dose of herbicide at any one time, so there is inherently less stress on the seedling."
Because of Degree Xtra's safety profile, it is registered for use on production seed corn and popcorn, as well as field and silage corn.
"In tests we have run, it came out as the safest corn herbicide product for inbreds, which are notoriously sensitive to injury," says Cole. "If it is safe for inbreds, you know it is safe for hybrids."
Degree Xtra and a companion herbicide, Degree, are the first herbicides to be commercialized using patented soil temperature-activated encapsulation technology, says Michael Seitz, the Monsanto formulation chemist who spearheaded the development. Degree contains encapsulated acetochlor without atrazine. It was marketed in limited geographies in 1999, under the name MON 58430.
"This is not a rupture-release capsule, as some of the older products," says Seitz. "Nor is it the same technology used in newer encapsulated products, such as TopNotch or FulTime."
The Monsanto technology used a patented blend of components to form tiny capsules that release larger amounts of the herbicide as temperature increases. The release range is continuous above 50 degrees Fahrenheit. As temperature climbs, more herbicide is released. If temperature falls, release rates also diminish-or shut off completely below 50 degrees.
At a soil temperature of 70 degrees Fahrenheit, it would take 30 to 40 days to release bout half the acerochlor in Degree Xtra. With technology used in other encapsulated herbicides, like TopNotch and Fultime, half of the active ingredient could be released within 24 hours under the same conditions, says Seitz.
"It is this superior encapsulation technology that makes Degree Xtra the longest-lasting residual control acetanilide on the market," says Baudler.