Cotton farmers looking for a cost-effective way to improve their weed control — and help stave off glyphosate resistance — in Roundup Ready and Roundup Ready Flex systems have a new tool this spring.

Monsanto is introducing a new herbicide formulation that contains metolachlor, an older residual herbicide labeled to control more than 20 grasses and small-seeded broadleaf weeds. The new product, Parrlay, will be offered with a rebate program to growers in selected cotton-producing states and counties.

“We want to encourage growers to proactively apply residual herbicides to prevent resistance,” said Jeff Wheeler, Monsanto's Roundup marketing manager. “I think most weed scientists would agree the pigweed situation, for example, is very manageable now. Once you get resistance, such weeds will be much more difficult to control.”

Applications of Parrlay will also help prevent early-season weed competition, a phenomenon that university researchers have shown can cause significant yield reductions in cotton.

Farmers can apply Parrlay pre-emergence or postemergence in a tank mix with Roundup herbicides to Roundup Ready cotton.

Besides early-season vegetation, the residual herbicide will also help control multiple flushes of problem weeds during the growing season.

“Cotton growers have told us they place a high value on Roundup Ready cotton technology, but they are concerned about the risk of glyphosate-resistant weeds,” said Wheeler. “To enhance their weed control program, we recommend adding a metolachlor-type herbicide such as Parrlay to Roundup Ready and Roundup Ready Flex systems.”

To back up its concern, he said, Monsanto will be offering a herbicide rebate to eligible cotton producers in Alabama, Arkansas, Georgia, Louisiana, Mississippi, North Carolina, South Carolina and Tennessee and selected counties in Florida, Missouri and Virginia.

Growers in those counties and states who purchase Parrlay herbicide from an authorized retailer and apply the herbicide at the Monsanto recommended rate and timing and plant Roundup Ready or Roundup Ready Flex varieties may be eligible to receive a rebate of $1.50 per treated acre.

“University weed scientists, crop consultants and Monsanto agree that a best practice for weed management is to use a variety of tools, including a residual herbicide,” said Wheeler. “We decided we needed to do more to encourage the use of residuals by introducing a new product and offering a rebate.”

He said Monsanto researchers see an advantage to applying Parrlay with the second Roundup application in Roundup Ready and Roundup Ready Flex systems, but that advantage may vary by region.

“Parrlay might go out in the first or second Roundup application in 3-inch to 6-inch cotton in the Southeast while in the Mid-South it might be targeted at 6-inch to 12-inch cotton and go out with the second application,” he said.

“This is consistent with our recommendations for a residual herbicide the last two years. We're suggesting now that it be done with Parrlay.

“We're working with university researchers and Extension to provide the latest information on the best approaches to applying these herbicides.”