On soybean farms around Louisiana, insecticides are used to manage and limit the populations of unwanted insects that cause severe damage to their crops. Few insects are more impactful than the redbanded stink bug, a small green pest that can cause millions of dollars of damage statewide.

To combat this, LSU AgCenter researchers have long-term tests to show which commercial insecticides are most efficient as well as the amount needed to have notable results. While these tests are important for farmers, there is rarely a change to the recommended chemicals used.

That changed this year when AgCenter researcher Dawson Kerns began testing isocycloseram, an insecticide with a new mode of action that seems promising in terms of both cost efficiency as well as lasting population control.

“We rely very heavily on a few insecticides and that puts us at high risk of the development of resistance,” Kerns said. “One of the biggest benefits of isocycloseram is that it provides a long residual control. It’s a premium product, but you get a lot of protection for a longer period.”

This will allow farmers to not need to apply insecticides as often, saving both time and money. While research has been going on for a few years around the country on isocycloseram, studies specifically on redbanded stink bugs are more limited to Louisiana, and the AgCenter will have more specific data and suggestions within the next few years for that chemical’s use.

Kerns and his team also have been looking into isocycloseram’s efficacy in tank mixes with other products against the redbanded stink bug.

Research also has been done by Kerns into the host preferences of the redbanded stink bug. The bug has been observed on crimson clovers early in the spring. But there is still a question as to what host the bug transitions to after this first stage and when they move into soybean plants.

“This trial is looking at alternative hosts for redbanded stink bugs and tracking their movement from different species of clover and then transitioning over to other species of legumes, before they move over to soybeans,” Kerns said.

There have been signs that point to the partridge pea as a likely transitionary host, but the study is still in progress.

While redbanded stink bugs are a serious pest for soybean farmers, there are also beneficial insects that reside in soybean fields and feed on pests. To better protect these insects, Kerns has begun a trial to study the impact of all the commonly used insecticides, along with isocycloseram, on beneficial insects.

Redbanded stink bugs are major pests for soybean producers and can cause significant yield loss every year. Photo by Avery Williams