The use of cover crops provides many benefits for farmland. Improving soil fertility, water penetration, and improving the amount of organic matter in soil are only three reasons why many producers sing cover crop praises.

However, as some Mid-South producers are currently being reminded, cover crops can also have a downside.

Just south of Marvell, Ark., soybeans were planted into a cover crop of Austrian winter field peas. Shortly thereafter, pea weevils were discovered chewing on the young soybean plants.

“The cover crop situation is not as widespread or shocking as some might believe,” says Gus Lorenz, University of Arkansas entomologist. “It is interesting, though.

“This is a relatively small incident on, perhaps, 1,500 acres. It comes after a similar thing occurred last year. I want to be clear: it is only associated with fields using Austrian winter field peas as a cover crop. The problem acreage is very limited.”

Pictures of damaged Arkansas crops

The pea weevils, says Lorenz, “get down into the debris, the cover crop residue and then feed on the plant. They cause a lot of defoliation and there are a lot of them. An application might take out a lot of them on the crop but there are plenty more still down in the residue, in the soil, waiting to move up. And the immature stage of the weevils feed on the nitrogen-fixing nodules of the soybeans.”

Producers are forced to keep chasing after the pea weevils. “You can spray and remove the ones in the crop, then they’ll come out of the residue or ground and you have to spray again. The grower gets into a situation where there’s a continual re-infestation because he can’t get control deep enough into the residue.”