Stink bugs are showing up in Delta crops, including rice, soybeans and cotton. The insects have slipped up on many producers, causing substantial yield losses over the last several years. The losses have many growers seeking ways to detect and avoid encounters with stink bugs.
A soybean producer told me last year that he had hired a consultant to watch his beans because the $30 to $40 per acre loss to stink bugs was too large. Since bean prices have increased, the detection of stink bugs is more important.
In soybeans and cotton, we have three primary types of stink bugs — brown stink bug, green stink bug and southern green stink bug. Of these, the brown stink bug is the most difficult to control.
In rice, the only stink bug of significance is the rice stink bug that feeds primarily on grains such as rice, grain sorghum and wheat and on wild species of grass with seed heads.
The brown stink bug and the two green stink bugs feed primarily on larger seed crops such as cotton and soybeans. They are also found in rice but do not cause any significant injury.
An excellent publication on the identification of stink bugs is available from the University of Arkansas Web site at http://publications.uaex.edu/.
Stink bug identification is especially important in soybeans and cotton, where the brown stink bug occurs primarily. A similar predaceous stink bug, the spined soldier bug, is often confused with the brown stink bug. Because the predator is a very effective enemy of many caterpillars that feed on crops, it is important to conserve it.
How do you control stink bugs?
First, you should know the treatment level for each crop. Those vary from state to state, but in general are very similar.
In soybeans, Arkansas recommends one per row foot or nine per 25 sweeps.
For cotton, one stink bug per 6 row feet or when 20 percent of medium size bolls show internal injury is the treatment level.
In rice, the treatment level is five bugs per 10 sweeps the first two weeks of heading and 10 per 10 sweeps the second two weeks of heading.
The level of control for stink bugs using various insecticides may differ. Most pyrethroids will control all stink bugs except the brown stink bug. The brown stink bug is most effectively controlled using Bidrin and methyl parathion. In cotton, bifenthrin or Capture and Discipline, is the most effective pyrethroid for controlling brown stink bugs, according to the ratings in the University of Arkansas insecticide recommendations.
Donald R. Johnson is a retired Arkansas Extension entomologist who consults on rice and cotton production in Arkansas.