Sugarcane Beetles Moving Into Louisiana Cornfields

No Foliar Control Agents Available

ST. JOSEPH, LA.

   Sugarcane beetles are moving from the sweet potato fields to the cornfield in Louisiana. Dr. B. Rogers Leonard, Field Crop Pest Management, Louisiana State University explained the devastation. “We’ve been seeing terrible injury in sweet potatoes recently. It’s a massive pest. Some fields are almost unharvestable. They literally have no controls for this critter. It seems to have moved out into cornfields, which is not a common host. We even see some injury in sorghum and cotton. I think these are consequential hosts; there is just nothing else for the sugarcane beetle to feed on at that point.”

   Producers have had to replant but according to Leonard, unless they go back into that field with a higher seed treatment, they are going to see the same injury. “It is an amazing insect in that when it first flies into the field, it burrows into the soil very, very rapidly. It is only a matter of a few seconds that if you try to put any insecticide out, that it would actually be susceptible. It basically burrows under the soil and moves from plant to plant.”

   The sugarcane beetle is a subterranean feeder. “It looks as if someone would take a spoon and just carve out the side of root systems of a plant. The injury is devastating. It literally kills the plants outright or those plants will die back. The remaining root system of the plant will sucker out. That plant then becomes a weed. If it does produce an ear, it is out of sync of maturity,” explained Leonard.

   “One sugarcane beetle per plant, or one beetle could damage several plants in a field,” added Leonard. “It is causing complete stand loss. There are no foliar control agents so you can’t stop the problem. You can’t recognize how serious it is until you go out and all of your plants are just basically wilted down, you pull them up and the root system has been destroyed,” stated Leonard.

   Leonard added seed companies are working on increasing their seed treatment dosage. “The seed companies have gotten concerned enough about it. Pioneer has recently put out a fact sheet on this problem. Syngenta is gravely concerned about it and are having discussions now with a possibility of increasing their seed treatment dose or working with the dealer/distributor network to bring those up. This has been a problem that has been occurring. We are on the tail end of it now, finishing up as you move north. If we don’t get it in this year, and certainly over the winter months, it is going to be a very hot topic. It is causing complete stand loss. The whole purpose of seed treatment is risk management; tools to try to maintain the plants in the field. To lose plants in this manner, we get in a serious bind. Corn acreage is likely to maintain itself so this issue is not going to go away in the mid-south.

  Unfortunately for our farmers in the south, sugarcane beetle is really a pest of Louisiana, South Arkansas, Mississippi and Tennessee. Very localized.” Δ

REGINA LAROSE: Associate Editor, MidAmerica Farmer Grower

On the move! Dr. B. Rogers Leonard, Professor of Field Crop Pest Management at LSU, notes the movement of sugarcane beetles and their damage.

Photo by John LaRose, Jr.