Pigweed grows on a large-scale research plot at the Sunbelt Ag Expo research farm. The Sunbelt Ag Expo annual field day will be July 13.

Big-acre research at Sunbelt Expo leads to wiser use of new pesticides

In order to better target pesticide applications, it is essential to understand drift and volatility of pesticides being used. For this, you need big acres to do research.

The Sunbelt Ag Expo Darrell Williams Research Farm located at Spence Field in Moultrie, Ga., has been a primary research location for University of Georgia Extension’s efforts to test and develop educational programs to help Southeast farmers better apply new auxin herbicides in-season.

“The Expo farm is my largest research site in the state of Georgia. We have about 22 acres, but they also let us use some of their additional acreage for drift studies. So this year, we could get closer to 30 acres of land on that one site,” said Stanley Culpepper, University of Georgia Extension weed specialist, who has conducted research at the Expo farm for 18 years.

In order to better apply, or target, pesticide applications, it is essential to understand drift or volatility of pesticides being used. For these studies, you have to have some big acres. “It can’t be done on a 30 by 50 foot plot. I’ve got to try and simulate what growers are doing, like treatments that are going out with the high-boy. The Expo farm is my link from small plot research to the real-world farming in agriculture, and they have been so wonderful to let me do that,” he said.

Culpepper will be one of several UGA Extension and researchers speaking at tour stops on the 2017 Sunbelt Ag Expo Field Day July 13.

His message, or focus points, for the field day this year will be: 1) improving management programs of palmer amaranth and other problematic weeds and doing it more economically with all the technologies; 2) continuing to improve research tactics and methods to better target on-target pesticide applications considering research boom heights, sprayer speeds and wind direction and speed, and 3) understanding the volatility of the new auxin herbicides.

There is little doubt agronomic growers in the Southeast need better ways to economically handle hard-to-manage weeds, and the new auxin herbicide formulations available now, or down the road, provide new tools for growers to do that. The new auxins have been formulated to reduce the risk of off-target, drift-related crop damage, and that’s good thing. And the language on the new herbicide labels provide specific and required strategies applicators must do which further reduce drift or volatile risk. The language on the labels also seems to put the responsibility of the herbicide application, on or off target, solely on the applicator. And that is important for growers to remember.

“One of my pet peeves is when someone says, ‘If you’ve done a good job with Roundup (on-target application), you don’t need to worry or won’t have any problems with in-season 2,4-D or dicamba applications,’” he said.

Not true. Culpepper said some crops widely grown in Georgia are 20 to 30 times more sensitive to dicamba or 2,4-D than they are to Roundup.

“Just because you were OK with Roundup does not mean you’re OK with 2,4-D and dicamba. In fact, you’re going to have to be better than you’ve ever been, and part of being better than you’ve ever been is deciding where you should and shouldn’t use these tools,” he said.

Culpepper expects the majority of Georgia’s cotton crop will be planted to auxin-resistant varieties in 2017, which will be done to manage hard-to-control weeds such as Palmer amaranth, morning glory and to a certain extent tropical spiderwort.

“In research-grade Palmer amaranth populations, the new technologies do offer slightly more flexibility and improved control over our standard practices with a few dollars less in hand weeding costs at seasons end,” Culpepper said. “It is critically important we have standard programs equally effective, allowing grower’s options. Those equally effective options do exist for most Georgia fields, but we do need to continue to improve our standard programs for the fields with heavy infestations.  For our growers who are able to be timely and aggressive, they are already achieving effective control with standard programs that offer lower off-target drift risks.”

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