What is in this article?:
- Scouting for soil insects in peanuts pays dividends
- Chemical control
• In Alabama’s peanut insect monitoring project for 2009-2010, more than 25,000 insects were trapped and more than 400 pounds of soil analyzed.
• Insects are attracted to peanut pods because the pods give off carbon dioxide and heat.
Scouting for soil insects pays dividends in peanut production, as evidenced last year by a few fields that were devastated by various pests, says Ayanava Majumdar, Auburn University Extension entomologist.
“Because we don’t see them very often, we tend to forget our below-ground insect pests, but last year opened our eyes,” says Majumdar.
In Alabama’s peanut insect monitoring project for 2009-2010, more than 25,000 insects were trapped and more than 400 pounds of soil analyzed, he says.
“Insects are attracted to peanut pods because the pods give off carbon dioxide and heat,” says Ayanava.
A major insect pest of Alabama peanuts in 2010 was the lesser cornstalk borer (LCB), he says, with many outbreaks being reported throughout the Southeast.
Many plant species play host to the LCB, and they’re able to survive and escape predators in dry soils. Like other soil insects, they’re attracted to carbon dioxide and heat from the plant roots, and they make sand tubes on pods and stems.
It’s very important, says Majumdar, to detect this insect early in the season so control measures can be undertaken. However, the only product currently available that is effective is Lorsban. “Scouting maps for the lesser cornstalk borer are available through the AWIS Weather Services website, and these can be very helpful.”
One grower in southwest Alabama lost 20 to 30 percent of his peanut crop in 2010 to LCB, he says. “Last year, we collected more than 5,000 lesser cornstalk borers in the fields, and that’s more than we want to see. We maintain a pheromone trap network across the state, and I personally scouted 30 fields last year,” says Majumdar.
Burrower bug numbers are up in some years and down in others, but several outbreaks were seen in 2010 in Baldwin, Escambia and Monroe counties in southeast Alabama, he says.
Adults and nymphs have piercing-sucking mouthparts that are inserted into mature kernels during feeding. Kernels develop light yellow to dark brown lesions as a result of this feeding, a damage called “pitting.”
“For farmers who are using conservation-tillage systems, these bugs do feed off of organic matter,” he says. For management of burrower bugs, do not strip-till peanuts into corn or wheat stubble to reduce the risk of feeding injury. Also, till in the fall, before planting, and destroy volunteer plants throughout the season for lower population buildup and risk to subsequent crops, advises Majumdar.