As Alabama peanut producers moved into September, average yield potential was holding steady at 3,100 pounds per acre, an improvement over last year’s average of 3,000 pounds.
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, says Austin Hagan, Auburn University Extension plant pathologist.
“I’d like to say I was responsible for getting rid of tomato spotted wilt virus, but it went away on its own. We haven’t had a lot of problems with it in recent years. Improved varieties all have a certain amount of resistance to TSWV,” said Hagan during the East Alabama Crops Tour held in late August.
As for insect pests, Alabama peanut producers saw one this year they’re not accustomed to dealing with — the aphid.
“We talk about aphids in other crops, but we normally never worry about aphids in peanuts,” says Ayanava Majumdar, Auburn University Extension entomologist, known as “Dr. A.”
“But in some parts of the state where weather conditions started off dry, and where soils were sandy, we saw aphids feeding on pegs.”
The species, he says, was the cowpea aphid. “You really have to look closely for this pest,” says Dr. A. “I have not seen it on the pods, but they will disfigure the peg. You may see some on very sandy soils. They are black insects with white legs, so they’re different from the cotton aphid.”
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.”