MSU advises on insect control
STARKVILLE, Miss. -- Insect pests are ongoing issues in row crop farming, and deciding when, how and whether to treat is never a simple decision.
Offered by the Mississippi State University Extension Service, the Row Crop Short Course in December featured sessions informed by MSU’s ongoing research that helps growers make management decisions. Several sessions addressed insect control from a variety of angles.
Whitney Crow, MSU Extension entomologist, discussed insect thresholds, which is the concentration of pests in a field that triggers an insecticide treatment.
“There is a decrease in yield as defoliation increases,” Crow said. “But it’s important to understand how yield potential and input could impact your decision to initiate a treatment.”
For example, if insect pressures build in a non-irrigated field during a hot and dry spell, a grower may decide to just tolerate the damage and potential yield losses when there isn’t a positive return on investment.
“Yield potential and budgets go together, and they really matter,” Crow said. “You have to figure out what needs to be done to ensure that everything pencils out.”
Crow said that economic thresholds serve as the starting point of insect management. These recommendations are generally management guidelines and are not always a one-size-fits-all. A crop with a high potential value is typically treated sooner than one with a lower potential yield.
While chemicals have been a primary control measure in recent decades, growers can follow other integrated pest management practices. These include earlier planting to avoid peak insect times and planting blocks of the same crop together to avoid field edges abutting different crops and potential insect pests.
Tyler Towles, an assistant professor at the MSU Delta Research and Extension Center in Stoneville, discussed the important ag chemical acephate and the Environmental Protection Agency’s proposal to cancel use of acephate that affects soil and water. No final decision has been made yet on this issue.
“The EPA is trying to limit the use of organophosphates in agriculture,” Towles said. “Tobacco thrips are one of the first pests we deal with every year, and we were already trying to move away from acephate.”
Growers have several options to manage thrips, beginning with a good seed treatment, early planting dates and careful crop rotation. Crop rotation is a good tool for on-farm pest management as different crops attract different pests, allowing different chemicals to be used so resistance does not build.
“At our trials in Stoneville, Sidon and Glendora, we are looking at excluding certain chemical classes and seeing the impact that has on pest populations and yield,” Towles said. “We’re also seeing that planting dates matter a lot in terms of plant bug management. If we planted earlier, we sprayed twice, but if we planted later, we sprayed six times.”
Despite the implementation of best management practices, some pests require chemical control. Towles said the EPA continues to implement label changes to protect health and the environment, and seed companies continue to research better varieties to withstand field and pest conditions.
Each year, MSU Extension and the Mississippi Agricultural and Forestry Experiment Station conduct field trials on the major row crops, always looking for updated management practices, how varieties perform in specific Mississippi conditions and ways to overcome challenges when they arise.
The results of these trials are compiled into annual publications to help growers make more informed decisions. Find the 2025 Insect Control Guide for Agronomic Crops at .
