Following a mild winter, red-banded stink bugs (RBSB) are a soybean pest that we should always have on our mind. Last Tuesday, 7/16/19, we found treatment level of adult RBSB at the Prattville experiment station. We found these in relatively early planted soybeans at R4/R5, and although we don’t have very large plots, we were exceeding 5 RBSB on 10 sweeps. That works out to about 3 times threshold and is a cause for concern for soybean growers in Alabama. This is a pest that we haven’t dealt with as much as the mid-south growers in Arkansas, Louisiana, and Mississippi, but they’ve put out some excellent info for control tactics that we can draw from.
RBSB’s are a tropical insect and behave and look different in many ways to the native stink bug pests we often deal with in soybeans, and the control tactics differ as well. RBSB are harder to capture with sweep net samples and time of day can have a large impact on the number you catch in the same field. In our plots in Prattville we caught 3 times threshold on 7/16 and 7/22 on warm mornings when the dew was still wetting the plants, but caught 0 on 7/18 during a hot mid-day. These stink bugs will drop off the plant very quickly when disturbed, and it may be hard to sample them in the heat of the day when they can evade capture or even on very cool mornings when they may be seeking shelter from the cooler temperatures.
RBSB’s should be controlled when populations average 4 adults or nymphs per 25 sweeps through R6.5, 10 adults or nymphs from R6.5 to R7, and should only be controlled after R7 if weather conditions are unfavorable. Cool and wet conditions can make mature soybeans more susceptible to feeding from RBSB, but if conditions will be favorable, no control is necessary after R7. RBSB are harder to control than our normal soybean stink bug complex and generally require a tank-mix to get adequate control and residual to keep them knocked back. Bifenthrin at 5.8–6.4oz with a half-pound of acephate is one of the most reliable control options. Bifenthrin can also be tank-mixed with imidacloprid at 3oz or Belay at 4oz and provide reliable control. Endigo at 4–4.5oz is also a good control option, but may not be available for many producers.
Aaron Cato, Post-Doctoral Fellow in Entomology
If you have any questions or concerns, please contact Ron Smith at 334-332-9501 or Smithrh@auburn.edu.
Adults are identified by their cigar shape when compared to normal stink bugs, the red band behind their head, and the clear/white spine extended forward between the legs as picture on the left.