Doug Johnson, Extension Entomologist, University of Kentucky.
If you’re not checking for stink bugs in your soybeans you should be. 2015 appears to be producing an extra large population of green stink bugs, at least in western Kentucky. For example, as of July 10, 2015, a total of 2,184 stink bugs have been captured in a black light trap on the UK-REC in Princeton, Kentucky. That is more stink bugs than were captured in all of last year (2014) in TWO black light traps on the UK-REC (e.g. 121 + 695 = 816). In fact, more stink bugs were captured in the 2015 single trap week ending on June 26th than in all of 2014). However one looks at it, that is a lot of stink bugs. In addition, you will notice a great deal of difference between the captures at the North Farm in Lexington –vs– The UK-REC in Princeton. This occurs almost every year, but is particularly apparent this year.
We have seen a decrease in capture since that high, but don’t let that fool you as the numbers will likely rise again. Black light traps only capture adult stink bugs. Because the bugs must be able to fly to the trap to be captured, and juveniles do not have wings, only adults are captured. Normally, we would expect to see three generations in each summer season. Sometimes this produces very distinct populations (See Figure 1.) but often the generations tend to show overlap with one another.
Sampling for stink bugs may be done by sweep net or shake
cloth. In Kentucky, most of our beans are in narrow rows so the sweep net is
the tool most often used. For sweeping, use a 15” sweep net and make 25 sweeps.
Then count the number of stink bugs present. Most of the stink bugs will be
green but there may also be brown stink bugs. In addition, juvenile stink bugs
may be multi-colored. You can tell them from the adults because they do not
have wings. Additionally, you will likely see some brown stink bugs whose
shoulders come to a very definite sharp point. These are spined-shoulder bugs
and are predators. They will not harm the plants. With the exception of
spined-shoulder bugs, count all stink bugs as the same.
If you’re not checking for stink bugs in your soybeans you should be. 2015 appears to be producing an extra large population of green stink bugs, at least in western Kentucky. For example, as of July 10, 2015, a total of 2,184 stink bugs have been captured in a black light trap on the UK-REC in Princeton, Kentucky. That is more stink bugs than were captured in all of last year (2014) in TWO black light traps on the UK-REC (e.g. 121 + 695 = 816). In fact, more stink bugs were captured in the 2015 single trap week ending on June 26th than in all of 2014). However one looks at it, that is a lot of stink bugs. In addition, you will notice a great deal of difference between the captures at the North Farm in Lexington –vs– The UK-REC in Princeton. This occurs almost every year, but is particularly apparent this year.
We have seen a decrease in capture since that high, but don’t let that fool you as the numbers will likely rise again. Black light traps only capture adult stink bugs. Because the bugs must be able to fly to the trap to be captured, and juveniles do not have wings, only adults are captured. Normally, we would expect to see three generations in each summer season. Sometimes this produces very distinct populations (See Figure 1.) but often the generations tend to show overlap with one another.
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| Stinkbug populatoins at UK-REC in 2013 |
