LSU AgCenter entomologist Sebe Brown has several research projects for controlling insect pests on corn, soybeans and grain sorghum.
One project, underway for more than 10 years, is the evaluation of neonicotinoid seed treatments on soybeans against three-cornered alfalfa hopper and wireworms.
Brown said the pests are particularly bad if soybeans are planted after wheat, but the seed treatments are showing a benefit.
“We don’t always see an increase in yield, but every year we see better vigor and stand establishment,” he said.
Another project involves the use of premix insecticides against stink bugs, particularly the redbanded stink bug.
The neonicotinoid component acts as a repellent and may have the effect of slowing down redbanded stink bug colonization in a soybean crop. “They don’t like what they taste, and they fly away,” he said
Brown said his work with a viral pesticide Chrysogen continues to show good results against loopers in soybeans.
“It works better some years than others,” he said.
The product seems to be more effective in cooler weather with high humidity. The product is inexpensive and is one of the more cost-effective insecticides. It is insect-specific, targeting loopers only, and it doesn’t harm beneficial insects, Brown said.
Brown’s research is showing the Bt trait still has limited effectiveness against corn earworms in corn. “We don’t see an economic benefit to controlling corn earworms in corn,” he said.
But borer populations are lower in Louisiana because most growers use Bt corn.
A new project is looking at the use of cultural practices, such as date-of-planting, row spacings and variety selection, in northeast Louisiana to control insects.
For grain sorghum, Brown has a project to determine if sugarcane aphids have become resistant to the insecticides Transform and Sivanto.
“The sugarcane aphid really changed things. It turned a low-input crop into a high-input crop,” he said.
The treatments are expensive, Brown said, but they are effective. And so far the aphids have not developed resistance.
This story is featured in the Louisiana Soybean and Grain Research and Promotion Board 2020 Report.
The LSU AgCenter and the LSU College of Agriculture