• By Daniel Stephenson, Donnie Miller, Sebe Brown and David Moseley •
Across the Louisiana, redbanded stink bug numbers are increasing as the growing season progresses. Louisiana State University AgCenter entomologists recommend the control of RBSB threshold populations until the soybeans are out of the field.
This means that the inclusion of an insecticide for the control of RBSB with a harvest aid application could be necessary (sodium chlorate cannot be tankmixed with any insecticide).
It is important to keep in mind, however, the restrictions placed upon many of the products at this point in the season. These restrictions may include total active ingredient restrictions and preharvest intervals.
Acephate, a common recommendation for RBSB control, can only be applied up to 2 lb ai per acre per year in Louisiana. Other insecticides also have increased restrictions, such as the pre-mix product Endigo with a PHI of 30 days.
It is important to read all label materials prior to any use of labeled product. When label restrictions prevent the inclusion of an insecticide with the harvest aid application, growers should not delay the harvest of soybeans so that the seed can be removed from the field as quickly as the label allows.
Table 1. Herbicides labeled for use as a desiccant in soybean.
|Active Ingredient and Rate||Formulated Product and Rate||Weeds Controlled||Remarks and Precautions|
|carfentrazone @ 0.016-0.023 lb/A||Aim 2EC @ 1-1.5 oz/A;
Add 1% v/v COC
|Better on morningglories than pigweed, sicklepod, etc.||Apply after crop has matured and grain has begun to dry down. More effective on annual vines. Do not apply within 3 days of harvest. Apply in 10 gal. by ground, 5 gal. by air.|
|saflufenacil @ 0.022-0.045 lb/A||Sharpen @ 1 – 2 oz/A;
Add 1% v/v MSO + 8.5 lb/100 gal AMS
|Morningglories and other broadleaf weeds||Apply once soybean has reached physiological maturity (all pods and seeds have no green color). Indeterminate varieties: 65% brown pods, more than 70% leaf drop, 30% or less seed moisture. Determinate varieties: more than 50% leaf drop and remaining leaves are yellowing. Preharvest interval is 3 days.|
|paraquat @ 0.13 – 0.25 lb/A||paraquat (2 lb/gal formulation) @ 8-16 oz/A;
paraquat (3 lb/gal formulation) @ 5.4-10.7 oz/A;
Add 0.25% v/v NIS; see label
|Desiccation of weeds and soybeans only||Indeterminate varieties: 65% of pods are mature or moisture content is 30% or less. Determinate varieties: 50% leaf drop and remaining leaves are yellow. Some drought stressed weeds will not be desiccated. Do not graze or harvest for hay. Apply in 20 gal. by ground or 5 gal. by air. Preharvest interval is 15 days. Immature soybeans will be injured.|
|sodium chlorate @ 6 lb/A||6 lb/gal formulation @ 1 gal/A;
5 lb/gal formulation @ 1.2 gal/A;
3 lb/gal formulation @ 2 gal/A
|Desiccation only. Level of weed control is affected by environmental conditions.|
Dr. Daniel Stephenson is a weed science professor. Dr. Donnie Miller is a weed scientist. Dr. Sebe Brown is statewide Extension entomologist, and Dr. David Moseley is state soybean specialist. All are with the LSU AgCenter.