Additional Weeds Targeted

Mid-South rice growers add a ‘plus’ to broadleaf weed control

New and improved weed control doesn’t come along too often, but rice growers added a plus to their rice management program last season. After four years of efficacy trials, Permit Plus received a 24c registration in 2011 and is available for use in Mississippi, Louisiana and Arkansas.

If the name sounds familiar, it is. Permit herbicide has been marketed by Gowan Company for more than six years. Permit Plus is a new formulation with the addition of thifensulfuron that has been registered exclusively by Gowan as a postemergent herbicide in rice production.

“This new, added value formulation improves the spectrum and consistency of broadleaf weed control in rice production systems,” says Eric McEwen, Global Brand Manager for Gowan Company. “While Permit herbicide has been a standard in rice weed control for many years, Permit Plus now provides more consistent control with the benefit of control of five other weed species.”

Those five extra weed species are: groundcherry, eclipta, Texasweed, ducksalad and morningglory. Additionally, more consistency of control has been achieved on certain species, notably smartweed, and control has been achieved with a lower active ingredient per acre. Trials at LSU have shown significant improvement in control with Permit Plus two weeks after application at .75 oz/acre as compared to Permit at 1 oz/acre evaluated in the same time frame.

‘More consistency of control’ noted

“The addition of thifensulfuron really expands its reach in our rice weed control program,” says Dr. Bob Scott, Extension weed specialist, University of Arkansas in Lonoke. “It’s excellent on smartweed, morningglory and hemp sesbania, which are key weeds in our area. It’s also an excellent tankmix partner that provides a broader spectrum of control that we really need.”

B.D. Fontenot, agricultural consultant with Crop Production Services in Elton, La., has worked with Permit Plus in research trials for two years. “It gets control and more consistency of control of troublesome weeds that are most important in this area.

“One that is especially important for us is Texasweed. That one is just hard to control, period,” he says. “A lot of the broadleaf weeds sprout over a wide range of time. Some herbicides will give you good residual, but they’re not as wide spectrum, and in some cases, not as efficacious on certain weeds that Permit Plus herbicide picks up. I think it’s going to be a valuable tool for us.”

Other state weed scientists are reporting similar results. “Permit Plus absolutely offers a broader spectrum of control,” says Jason Norsworthy, Associate Professor, University of Arkansas in Fayetteville. “Smartweeds can be very problematic in our area. It’s in the top 10 to 15 weeds in Arkansas rice production, and Permit Plus, with the additional active ingredient, provides more consistent control. That benefit, in combination with some of the extras that the product picks up, makes it a valuable addition to our weed control arsenal.”

Fontenot adds a word of caution. “You have to use the full labeled rate,” he says. “You can’t skimp on the rate and expect the best results. Some of these weeds are very difficult to control.”

A fit for other crops and fallow applications

For 2012, Permit Plus is labeled for pre and post applications on sufonylurea-tolerant soybeans (STS). “For soybean growers, it is important to keep this option for weed control and evaluate the potential benefits of using Permit Plus on STS soybeans when making seed selections,” notes McEwen.

“In addition, Permit Plus can be used in fallow applications to help clean up persistent weeds that may be problematic in rotational rice crops.”

Information for this article was provided by Gowan Company.