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.
After 41 years in the business, one might think that an entomologist would run out of new things to talk about.
Not so, says Ron Smith, long-time Auburn University Extension entomologist, who says 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, said Smith, speaking at a recent Certified Crop Advisor Training in Auburn, Ala.
One of those sporadic pests is the garden fleahopper, a small insect that has been found in Mobile County, Ala., in recent years, he says.
“This past year they were also in Baldwin and Monroe counties, on cotton as well as in peanuts. They will speckle every leaf in the field. One of our growers applied a pyrethroid this past season, but it wasn’t very effective. We think it’s an economic pest in those fields where it occurred.”
Grasshoppers continue to be a problem from central Alabama into the southern portion of the state, especially in reduced-tillage situations, says Smith.
“They’re in the field during the cotton seedling stage — when they can cut off the stems — and they’re out there by the thousands per acre. I would call them a risk insect because they’re a risk to stands, and with the cost of seed and technology today, you have to manage this risk just as you would an insect later in the season.
“I don’t think we’ll ever have an exact, established threshold for grasshoppers, and the problem is much greater where we have reduced-tillage.
“When growers do their winter wheat burndown in March or April is when we’d want to mix something in there with the herbicide to target grasshoppers in the immature stage,” says Smith.
Almost anything labeled for cotton at the lowest labeled rate will kill immature grasshoppers, he continues.
“We could add a couple of ounces of Dimilin, and that would give us some residual control through the spring because there’s always the possibility there would be some infestation from field borders again.
“If you wait until later, like in May, most of the grasshoppers will be adults and you can’t kill them with a sledgehammer. There’s nothing you can do to wipe out adult populations. The problem ends when cotton gets to the fourth or fifth true-leaf stage,” says Smith.
The three-cornered alfalfa hopper also can be a pest of cotton, he says. “I wouldn’t say they were tremendously economic, but you’ll see a stunted, peculiar type of red cotton plant associated with girdling by three-cornered alfalfa hoppers. You’ll also see that problem in soybeans. On cotton, they’re worse during dry springs and in field borders.”
Smith says he gets a lot of call each spring about the burrower bug, but the consensus is that it’s not an economic pest of seedling cotton. It’s a different species from the one that causes problems on peanuts, he adds.