What is in this article?:
- Alabama peanut crop looks good at finish line
- Burrower bug a concern
• As of mid-September, 13 percent of the state’s crop was rated in fair condition, 79 percent was good, and 7 percent was rated as being in excellent conditions.
• Plentiful rainfall in the state this season has caused a few serious issues with white mold disease, but overall, disease pressure has been contained as most growers have stayed on a good schedule for controlling early and late leafspot.
AUBURN UNIVERSITY Extension Entomologist Ayanava Majumdar is shown demonstrating how to detect burrower bugs in a peanut field using a yardstick to expose the pods.
Burrower bug a concern
Burrower bugs continue to be a concern for Alabama peanut producers, he says, and damage from this pest occurs very quickly. “At this point, we don’t have a monitoring or prediction system as we do for caterpillars. They are in the stink bug family, with piercing and sucking mouthparts. They will go through the peg and feed on the pods. And anytime you have soil pests, you’ll have aflatoxin,” he says.
Burrower bugs are late-season pests, and insecticides are not a solution to the problem, says Dr. A.
“A late-season shot of an insecticide usually will flare mites and other problems. Mites are incredibly hard to deal with and to detect. A late-season shot of Lorsban is not recommended. Burrower bugs are more associated with conservation-tillage systems. If you have too much trash on the top of the ground, burrower bugs will hide in it and feed on the organic matter.”
When scouting for burrower bugs, look for a one quarter-inch long insect with overlapping, semi-hardened wings and spiny legs that run fast on the soil surface when disturbed. Both burrower bugs and lesser cornstalk borers are insects that like the dry weather, but usually don’t get severe in wet weather. Irrigation will be important as peanut pods fill and as growers move to harvest, says Dr. A.
“There are several species of burrower bugs, and 50 percent of the calls I get are about species we aren’t worried about. The one we are worried about is all black in color, and it has spiny legs. It’s about 2 to 3 millimeters long, so it’s not a very large insect. You can’t see this pest just by looking at the foliage — the foliage won’t tell you what’s going on in the ground.
“When I scout, I carry a yardstick to push back the soil and expose the pods. It gives me a nice 3-foot sample, and it does a good job of exposing the pods. Always look at both the pods and pegs, because those burrower bugs will start coming to the pods, and as the pods form, more and more will migrate to the field. They will feed directly on the pod.”
Lesser cornstalk borers also continue to be a problem in sandy soils, says Dr. A. “In three years of monitoring, we’ve had hundreds of moths flying in the fields, but the rains keep them away.”
Tillage and irrigation remain the two keys to controlling burrower bugs, he says. Pyrethroids will only flare other problems.
“We haven’t seen much worm pressure on peanuts this year except from the velvetbean caterpillar. The threshold is four or more caterpillars per foot of row. Improved varieties have better tolerance of foliar pests, so our main battle is with the soil pests, where there is no resistance.”
Radiant is now registered as a foliar insecticide for peanuts, and it’s effective on caterpillars and thrips, says Dr. A.
“It’s a selective product, so there’s not such a good chance of flaring other insect issues. It’s a different chemistry from pyrethroids. Don’t use pyrethroids just because they’re cheap. Belt is another new insecticide in the arsenal. These new products are more pricy, but hopefully the prices will go down as we demonstrate a market for them. Intrepid is another good one for rotating.”