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Adult brown stink bug (left), adult southern green stink bug (center), and immature redbanded stink bug (right). Photos by J. Villegas
More stink bugs are starting to show up in soybean fields. The stink bug complex in Louisiana soybean includes several species such as the brown stink bug, green stink bug, southern green stink bug, and perhaps the most notorious, the redbanded stink bug. Each species is capable of causing damage. Stink bugs possess piercing-sucking mouthparts that enable them to feed on various parts of soybean plants (stems, pods, and seeds), potentially causing yield and quality losses. The redbanded stink bug stands out as the most economical insect pest due to its extended feeding behavior and ability to pierce deeper into pods.
To stay ahead of these insect pests, regular scouting using sweep nets is essential. Scouting not only helps determine the presence of stink bugs but also aids in deciding the appropriate control measures. For redbanded stink bugs, the threshold recommended by LSU AgCenter is 4 bugs (nymphs and adults) per 25 sweeps, while for southern green, green, and brown stink bugs, the threshold is higher at 9 bugs (nymphs and adults) per 25 sweeps. When it comes to control, different species require different approaches. Please check the 2023 LSU AgCenter Insect Pest Management Guide for recommended insecticides.
While the standard recommendation for controlling southern green, green, and brown stink bugs is to cease insecticide applications once soybeans reach the R6.5 growth stage, the same cannot be said for redbanded stink bugs. Due to their extended feeding period and deeper pod penetration, soybeans must be protected from redbanded stinkbugs until at least the R7-R8 growth stages. Previous studies have documented an average seed weight reduction of 10% if redbanded stinkbugs are not controlled past R6.5.
When applying final treatments, particularly when tank-mixing pyrethroids with acephate or neonicotinoids, two critical factors should be kept in mind: the pre-harvest interval (PHI) and the maximum active ingredient (a.i.) allowed per acre per growing season. Adhering to these guidelines ensures both effective pest control and compliance with safety regulations.
Written by
Dr. James Villegas
Assistant Professor - Extension and Research
Field Crops Entomology
LSU AgCenter
Email: jvillegas@agcenter.lsu.edu | Mobile: 225-266-3805
