Insect Action Picking Up In Early Maturing Soybean Fields

JACKSON, TENN.
   Some of the especially early fields are holding threshold levels of green stink bugs at this time. This is not the norm, but it is not uncommon to see this in fields that are considerably more mature than surrounding fields. Stink bugs are primarily seed feeder. Early maturing fields can serve as a kind of traps crop, sucking in stink bugs looking for an early meal. This is why it is a good idea to sample fields before applying fungicide. The recommended treatment threshold for stink bugs is an average of 9 per 25 sweeps.
   I’ve also observed a few more bean leaf beetles that I’m used to seeing in some of these same fields. We have a threshold of 2 bean leaf beetles per sweep (200 per 100 sweeps), so it takes a lot to cause economic injury. However, they can contribute to threshold levels of defoliation (20- 25 percent from R1 – R6) when they occur combination with other defoliating pests. 
   I’ve had several calls about “loopers”. My first thought was we had some cabbage loopers, which are much more likely early season than the more difficult to control soybean looper. However, I visited one of these fields and discovered they were actually green cloverworms. The other fields certainly could have had cabbage loopers, but this reminds me that we need to be able to accurately identify our caterpillar pests in soybean. The difference in control costs for controlling cloverworms or cabbage loopers versus soybean loopers is considerable. Soybean loopers are resistant to pyrethroid insecticides. Δ
   DR. SCOTT STEWART: IPM Extension Specialist, University of Tennessee

Bean Leaf Beetle