What is in this article?:
- Kentucky soybean farmers: Donâ€™t forget about stink bugs
- Stink bug sampling in narrow or wide rows
- Stink bugs hang around until frost. In soybeans, the pods are at risk up to the R6 stage. So if you have beans less mature than this you should definitely be looking for these critters.
- Synthetic pyrethroids commonly control green stink bugs. Brown stink bugs are a bit more tolerant of pyrethroids. If they are plentiful, inclusion of an organophosphate like acephate may be needed.
DUE TO DELAYED planting and a cool summer, some Kentucky soybeans are still filling pods, and this leaves them open for late-season damage from stink bugs.
Stink bug sampling in narrow or wide rows
In wide-row beans, a shake cloth, or drop cloth) may be used. This is a 3- foot long section of white cloth wide enough to reach from row to row. Shake the beans on both sides over the cloth and count the stink bugs that fall to the cloth. Adults can fly so you need to count quickly. Juveniles do not yet have wings so they are a bit slower to escape.
In narrow-row beans, use a sweep net. The 15-inch-diameter sweep net is the standard tool for most thresholds. Take 25 sweeps per location and count the stink bugs captured. In both types of sampling, each field should be sampled at multiple locations. The more locations you sample, the more accurate and precise your estimates will be. Average the number of stink bugs captured over all locations.
Thresholds that warrant control are when with a shake cloth an average of one stink bug per row foot, or if sampled with a sweep net, treat if you collect an average of 9 stinkbugs per 25 sweeps at R4-R6.
If control is required, synthetic pyrethroid insecticides are commonly used for control and are very effective on green stink bugs. Brown stink bugs are a bit more tolerant of pyrethroids. So if they are plentiful, inclusion of an organophosphate like acephate may be needed.
Producers in the central and eastern Kentucky production areas need to keep their eyes open for the two invasive stink bug species. Populations of the brown marmorated stink bug, or BMSB, have become established in central and eastern Kentucky over the last 3 years. BMSBs look typically like other brown stink bugs except that they are often a bit larger and have two small but very distinct white bands surrounding the joints in their antennae. In addition, the Kudzu bug has been found in three southeastern Kentucky counties bordering I-75. They are dark green to olive with a rounded shape and about the size of an English pea.
Neither of these species is believed to be of major importance in this year’s crop, but as their populations become established and grow larger in size they have the potential to become major soybean pests.