As much as Bob Beakley dislikes insecticides in soybeans, stinkbugs often leave him no choice. It's spray or pay.
The Ennis, TX, soybean, corn, cotton, grain sorghum and wheat producer farms with his son, Steven. They have learned to get ahead of stinkbugs before damage begins to smell. “We often see stinkbugs the first or second week of June,” says Beakley. “We must apply a heavy dose of insecticide to control them.”
Stinkbugs, either the brown, red-banded, green or southern-green type, have been common in the South since 1970. The red-banded became a major problem in about 2004 when growers began seeing some damage.
Inserting their beak into the pod, stinkbugs suck out the contents of the bean, resulting in complete loss of the bean or a delayed maturity. Among the damage is the “green bean syndrome,” in which plants infested with three to six bugs remain green longer. It can delay harvest by three weeks.
In early infestations, barrel-shaped eggs are laid on leaves in clusters in tight rows. Adult bugs are the size of a small corn kernel.
According to Jack Baldwin, Louisiana State University entomologist, five to eight generations of stinkbugs may occur in one growing season. Adults, nymphs and eggs may be present simultaneously in the same field by mid-summer.
For brown, green or southern-green stinkbugs, 1 bug/row/ft. or 36 stinkbugs in a sweep sample of 100 sweeps is a common economic threshold in some cases. But in some areas, it may be as high as 4/row/ft.
“Red-banded stinkbug is sort of a different critter, compared to the southern, green and brown,” says Baldwin. “We have a lower threshold for it, 24 bugs per 100 sweeps.
“The insects are smaller than the southern-green stinkbug and brown stinkbugs,” he says.
Keeping stinkbugs under control is important to Beakley. He likes soybeans in his rotation with wheat and takes advantage of the nitrogen available from bean residue and the soil. Planted in 30-in. rows, beans are mostly Roundup Ready.
Insect control is usually nota big problem - except for red-banded stinkbugs.
Using a John Deere 4720 90-ft. boom sprayer, stinkbug treatment starts in about the third week of June. “We apply about 10 oz. of Orthene (acephate),” says Beakley. “That's a pretty heavy rate. But it is within the label and one spraying usually provides the control we need.”
Because the insect is relatively new in the Louisiana, Texas and Arkansas area, entomologists are basing their approach to control on their experience with other stinkbugs.
Given the difficulty in controlling them, we're hoping the pest won't be a perennial problem, says Baldwin.
He recommends red-banded stinkbug control using from 0.75-1 lb. of acephate active ingredient per acre. If a suppression or less-than-optimum control is needed, then a Baythroid pyrethroid application of.0044 lbs. of active ingredient should work.
Beakley works with regional Extension personnel to study soybean production, including insect control. “We have soybean, corn and wheat plots with Texas Cooperative Extension. We can identify the top varieties for our area. And we can learn more about stinkbug and other production problems,” he says.