What is in this article?:
• One of the problems that has arisen over the past 10 to 20 years is that we don’t scout peanuts like we did in the 1970s or early 1980s.
• The problem is that one of the easiest things to drop in peanut production during years of potentially low returns is scouting or pest management.
• Insects are highly variable in how their populations attack peanuts.
SCOUTING PEANUTS FOR insects has become a lost art in many fields, causing the emergence of certain pests.
Spider mite explosion
“Over the last 30 years, there might have had been five to seven years when we had real spider mite problems in a general sense. But last year, we did not anticipate the problems in fields where we were not observing very closely, and we let spider mites explode on us before we made any attempt to control them,” he says.
Spider mites are fairly small, says Adams, and most anyone under the age of 30 could see one if they turned the leaf upside down. So when you can see spider mites from the highway, you’ve got a problem.
“Last year was probably the exception to the rule. Years ago, cotton actually was killed by spider mites, and spider mites also can kill a peanut plant.
“There are things we should be aware of when dealing with mites, especially in a dry year. If we harrow or mow field borders after layby, then mites will move into the field. And if the field borders have dried up and died, they’ll move to the peanuts because they’re green,” he says.
Treatments with products like Lorsban can exacerbate spider mite problems, says Adams. This doesn’t mean that growers shouldn’t use Lorsban, or that it isn’t effective for other problems.
“But we have to watch those fields in which we use it for potential spider mite, cutworm and other worm problems. We do kill off a lot of the ground-dwelling predators that live in peanuts.”
Growers many times use pyrethroids with their fungicides to knock out three-cornered alfalfa hoppers, says Adams. “A pyrethroid application typically won’t make something else explode in the field.
“But if we use multiple applications of pyrethroids, we have a tendency to cause problems with other insects, especially foliage feeders.”
Pyrethroids do kill thrips, he says, and thrips is a native predator of mites.
“Typically, we don’t have to use a lot of acetates on peanuts, and we should be worried mostly about in-season applications. It kills a lot of insect pests, and it kills a lot of predators.
“It also hangs around for awhile. It’s still a good insecticide, but you should be judicious in how you use it.”
If you make herbicide rescue treatments in the field, it’s important to remember that mites reside on those weeds, says Adams. If you kill a preferred host, then the mites will move into the peanuts, he adds.