What is in this article?:
- Entomologists contend the southward movement of the brown marmorated stink bug is almost certain to continue.
- Virginia Tech Entomologist and IPM Leader Ames Herbert says brown marmorated stink bugs, sometimes called Asian stink bugs, have reached soybean fields in northern Virginia and appear to be moving from full-season to double-crop beans.
Easy to find
Herbert says these critters are easy to see on soybean plants and easy to catch, but unlike their American stink bug cousins, Asian stink bugs have an amazing startle reflex. “They quickly drop to the ground when the plant they are on is disturbed. I can stop, move close to take a picture of one of these stink bugs, and it will fall off the leaf to the ground,” Herbert explains.
The startle reflex doesn’t mean much to farmers — at least not yet, but it makes life very frustrating for researchers trying to learn more about these pests. It makes setting an economic threshold for these bugs very difficult, Herbert notes.
Not only did brown marmorated stink bugs make their way to the upper Southeast, but they appear to have brought their favorite native habitat with them. BMSB are listed as an invasive insect species and the tree-of-heaven, also native to Asia, is listed as an invasive plant species.
Tree of heaven is now common throughout most of Virginia. In the areas of north-central Virginia where Asian stink bugs have caused damage to soybeans, this weed species is everywhere. Many of the soybean fields in Virginia that have been infested with the Asian stink bug are small, irregular shaped fields with tree of heaven growing right up to the field border.
“In some of the soybeans fields we’ve looked at up there, we can find damage in the field, go to the edge of the field and find a tree-of-heaven, tap a limb and dozens of the bugs fall out. Farmers have tried cutting the weed/tree down, but they sprout back out quickly,” Herbert says.
The veteran Virginia Tech Entomologist adds that getting rid of tree-of-heaven wouldn’t likely do much to stop the southern movement of Asian stink bugs. These insects have hundreds of hosts, and though they do seem to prefer the tree-of-heaven, there are plenty of other plant hosts that suit them well.
Despite all the hoopla about the brown marmorated stink bug, it is not a super bug, according to Herbert.
There is no doubt it is a serious pest that needs a lot of attention, but many of the insecticides we have in our arsenal will kill it. The problem is populations build back up very quickly, and we don’t seem to be getting much residual activity from the insecticides we’re using to control them, he adds.
One management strategy that seems to be working in north-central Virginia is treating the field edges, up to 30-40 feet in from border areas. Herbert says that damage to soybeans has been largely restricted to the outer rows of a soybean field. Treating and re-treating these areas seems to be holding up as far as controlling populations found in these bean fields.