Loopers, stink bugs, other soybean bugs focus of research

Because of the complicated winter, LSU AgCenter entomologist Jeff Davis said he’s not sure what to expect from insect pressure this growing season.

“After the ‘snow-mageddon,’ or whatever that was we had with the ice and snow, we will just have to wait to see how it affected the insect populations,” Davis said.

After the mild winter of 2019, there was an increase in insect pressure in soybeans. This year, Davis has Tyler Musgrove and Scott Lee, two graduate students, to help with the research.

Musgrove is a master’s student, and he is working on insect thresholds. Lee, a doctoral candidate, is working on stink bugs and soybean loopers. His project looks at how control measures for stink bugs affect the looper population.

“What he’s doing is looking at natural enemies, the impacts of the introduction of various insecticides,” Davis said.

Musgrove’s work has been focused on the three-cornered alfalfa hopper’s thresholds during the late season, he said.

Mississippi and Arkansas have reduced their thresholds and most of previous three-cornered alfalfa hopper work was done by LSU AgCenter scientists during the early 1980s, and those thresholds have stood the test of time, Davis said.

“We want to make sure that whatever we’re giving our growers has our seal of approval,” Davis said. “Tyler is looking at late-season applications and the impacts of different seed treatments.”

Lee is looking at the best times to apply insecticides for the stink bugs, Davis said.

“When we apply insecticides for the stink bugs, we need to know how that affects the population of the loopers,” he said.

Davis said anytime there is an insecticide application made, it actually causes a change in the entire insect complex.

“We want to make sure when we tell a grower to make an application that he doesn’t get rid of one problem but create 20 others,” he said. “We want to give them the best options, with the best price. In other words, the inputs don’t cost that much, and it gives them the best control.”

Davis said there are three different chemical options that he will give to growers for stink bug control, neonicotinoids, pryrethroids and organophosphates.

After the stress of trying to conduct his research during a pandemic, Davis said his research is being done this year in Hessmer, Washington, and in Alexandria. In 2020 he was confined to working in Baton Rouge.

Lee said his findings show that an increase in applications for stink bugs causes an increase in looper populations.

“What this means is when you make an application for stink bugs, it would be a good idea to also make an application for loopers as well,” Davis said.


LSU AgCenter entomologist Jeff Davis, left, and entomology graduate student Tyler Musgrove explain how they use a modified piece of equipment to collect stink bugs and other insects. Photo by Johnny Morgan
9/17/2021 9:08:12 PM
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