What is in this article?:
• There’s always something new and different in the world of crop insects.
• There are sporadic and incidental pests and then there are others that can be counted on to cause problems every year.
AUBURN UNIVERSITY EXTENSION Entomologist Ron Smith, shown here during a field day this past summer, says there are always new things to talk about in the world of crop insects.
Brown marmorated stink bug
“The brown marmorated stinkbug is one we’ll likely see in the future on both cotton and soybeans, but probably more in home gardens and on vegetables and fruits,” says Smith.
“It’s a native of Asia. It first showed up in Pennsylvania around 2000, and it’s moving south into the Carolinas, causing severe problems on fruits and vegetables. It’s now in soybeans in Virginia and North Carolina.
“We know they like cotton and corn, and they will be a lot more damaging than the stinkbugs we have today because their snout is bigger and stronger, and they can go through an older cotton boll better than our regular brown and green stinkbugs. They also can go through a corn ear more readily. They will be a major pest at some point.
“They are good hitchhikers, so we either already have them here or we’re going to have them — it’s just a matter of time. We should be okay with controlling them with the materials we have, such as the pytrethroids.”
Snails, slugs and pillbugs all can cause economic stand losses in cotton, but most of the losses are from slugs, he says.
“They’re under the crop residue in the daytime, and people associate their damage with the pillbug. But of these three, slugs pose the greatest threat. They’re more common in cotton planted behind corn because there’s more residue, and they’re more common in wet springs.
“There are no effective controls for any of these — you just have to take the loss and replant if necessary.”
The kudzu bug has become a popular topic of conservation for growers, says Smith.
“They are very small when they are hatched, and the adults are not as big as a stinkbug. A lot of people don’t see the immature stage on the stem, and that’s probably the most critical damaging stage.
“In 2009, they were found around Athens, Ga., and in 2012, they were spread throughout Alabama and scattered into Mississippi and Tennessee. They’re also great hitchhikers.
“They are a major pest of soybeans in the Carolinas and in Georgia. Yield losses are up to about 50 percent, but on the average, where they’ve conducted a lot of trials, the average loss is about 20 percent in the untreated plots.”
Kudzu bugs are stress inducers, says Smith, causing fewer pods per plant, fewer seed per pod, and reduced seed size.
They move from kudzu to other hosts such as soybeans in mid-June to mid-July, and early planted beans are at the greatest risk.
“You can survey them with a sweep net or visually survey them. We’re looking for one adult per sweep, but the key is the presence of these immature bugs on the plant stem.
“That’s when we want to spray. If you spray whenever you see adults in a field, you’ll be spraying every week all summer once they get into soybeans.
“My counterpart in Georgia last year properly timed one insecticide spray and controlled them in Tifton. That was around July 20-25.
“I’m saying one or two well-timed insecticide applications will be all that is needed. In Alabama, that would be from July 15 near the Gulf Coast to Aug. 1, in the Tennessee Valley.”