Using Ignite herbicide on Phytogen cotton that contains the Widestrike gene for insect management is becoming a popular practice for growers in Virginia and North Carolina, despite warnings that the practice may damage the crop, leaving the grower no recourse, if things go wrong.

“This is our fifth year of using Ignite on Phytogen cotton, and we’ve had little damage — none that we feel has reduced our yield,” says Windsor, Va., grower Paul Rogers.

Rogers says he fully understands the risk, but feels it’s justified as long as he keeps a watchful eye on the weather. “Some growers in our area have gotten some fairly severe burn using it, but that’s only when it is applied in the heat of the day or if they add an adjuvant to it,” Rogers adds.

In Capron, Va., Cliff Fox says he does get some burn on some of his cotton from using Ignite on Widestrike cotton. “We’re careful of how we use it and when we apply it, but still you can see some burn sometime, but not enough to damage our yields,” he says.

“I learned real quick when to ‘not’ spray it — 11 o’clock in the morning is definitely not the right time. I thought the leaves would be tough enough by that time, but after a few days you could see the burn. I sprayed a different field about 6 p.m., and I couldn’t see any burn,” Fox says.

“Waiting later does reduce the burning on the cotton plants, but I’m concerned we may not be getting quite as good weed control by waiting until late in the afternoon to spray it,” Fox adds.

Both Bayer CropScience, which sells LibertyLink cotton varieties that are tolerant of Ignite herbicide, and Dow AgriChemical, which sells Phytogen Widestrike cotton seed frown on the practice. Both claim no responsibility if growers damage their crop, but the practice is legal, as long as growers follow label restrictions on the herbicide.

Weldon, N.C., Crop Consultant Daniel Fowler says the value of using Ignite herbicide on cotton is to help growers avoid or reduce the risk of yield loss from glyphosate resistant pigweed.  “I make real sure the grower understands that the gene in the Widestrike cotton is similar to, but not the same as the gene that makes it safe to spray Ignite herbicide on LibertyLink cotton,” Fowler says.

The North Carolina crop consultant says he is seeing more and more pigweed that appears to be resistant to Roundup (glyphosate). “We’ve seen what kind of problems growers in the central and southern parts of the state have had with Roundup resistant pigweed and marestail, and we’re doing everything we can to try and stay away from those kinds of problems up here,” Fowler says.

Fowler adds that a few growers have had significant burn problems if they tank-mixed Ignite with AMS (ammonium sulfate). “And, if you have to apply it before the crop comes up, Ignite can be finicky, but when used at the right plant growth stage and applied at the right time of day, few growers have had any problems at all using Ignite on Widestrike cotton,” he says.

University of Georgia Weed Scientist Stanley Culpepper has done a number of research projects with the LibertyLink System and explains the genetic process that renders LibertyLink cotton varieties tolerant to glufosinate, the active ingredient in Ignite herbicide.