Rome Ethredge, Contributing writer
I remember one year a grower was going to plant peanuts in a small field that had been in pasture for over 15 years. He said the last time he had peanuts there he had noticed some nematode damage at harvest time. We thought that with the good rotation, he shouldn’t have a problem. We were wrong.
The peanut root-knot nematode (Meloidogyne arenaria) is a force to be reckoned with and caused yield limiting damage again after all those years since we used no nematicide or resistant variety.
Here in deep south Georgia, we are always considering the nematode, but what got me really thinking about them is the mild winter we’ve had so far. Up until the second week in January, we still had cotton, peanuts and corn growing in many spots. I pulled up plants and saw actively growing root systems. Nematodes have likely been surviving on these root systems.
Nematodes are some of the most common animals on earth. There are about a million types of them worldwide, second only to insects in diversity. We don’t often see them, however, due to the fact that many are microscopic. But some are large, like those found in whales that can reach 20 feet in length. About 10 percent are plant parasitic, and those are the ones that really hurt agriculture. What can we do?
Among actions to take are crop rotation, resistant varieties, chemical control (including fumigants) and crop destruction. And just because we didn’t have a problem in cotton last year doesn’t mean much if we will plant peanuts in the field this year. We need to consider the last time peanuts were in that field, like my friend who switched from pasture to peanuts and still had nematode damage. Nematode sampling is a good thing but it must be done right and the sample kept in good shape until it gets to the lab. What must be considered is what crop had just grown in the field when the sample was taken.