TEST Brown Marmorated and Other Stink Bugs

  • The brown marmorated stinkbug (Halyomorpha halys) (BMSB) is a pest that was discovered in the United States in during the 1990s.
  • The BMSB feeds on the fruits and seed pods of a wide range of plants including corn and soybeans.
  • Additional stink bug species affecting crops are green stink bug, Acrosternum hilare (Say) and brown stink bug, Euschistus servus (Say) (BSB) with corn field infestation early in the season and soybean fields later in the season.

Topic

Figure 5. Symptoms of brown marmorated stink bug  damage may include misshapen ears. Photo courtesy Dr. Angus Catchot, Mississippi State University.

Generally, stink bugs are shield-shaped, have long piercing-sucking mouthparts, and often release an odor when crushed. 10;10;Brown marmorated stink bugs (Figure 1) are mottled shades of brown and gray and are covered with dense puncture marks on the upper side of the body. The underside of the body is white, sometimes with gray or black markings. They have dark red eyes and the legs are brown with faint white banding. Broad light and dark bands on the last two antennal segments distinguish BMSB from other stink bugs.  10;10;Green stink bugs (Figure 2) are bright green in color and measure 14 to 19 mm long.1 A narrow, orange to yellow line borders the major body regions of the green stink bug.  10;10;Brown stink bugs (Figure 3) are commonly found in corn.  The adults have a shield-shaped body nearly 12 to15 mm long and are dull grayish-yellow in color.

 

Effect

Figure 6. Shrunken and unfilled kernels may indicate BMSB damage. Photo courtesy Dr. Galen Dively, University of Maryland.

Damage occurs when stink bugs insert their needle-like mouthparts into the plant tissue, injecting enzymes to dissolve the tissue, then sucking out plant sap.  At the location of feeding punctures, small brown to black spots may be formed.  

Weekly scouting that begins two weeks after corn emergence can be helpful in managing stink bugs.  Especially in the case of BMSB and BSB, growers should scout field borders near host plants (including woods, wheat, and fruit orchards). Thresholds vary widely and are still being developed for brown marmorated stink bug in some states.  
When plants reach the ear elongation through pollen shed stages, treatment may be warranted when the threshold of 1 bug per 4 plants is reached (25% infested). Fields in the later part of pollen shed and in the blister/milk stage can be treated if there is 1 insect per 2 plants (50% infested).2
Corn ears are more prone to damage especially during tasseling.  Corn ear damage may be hidden when husks covering ears are pierced by stink bugs and hide blemished kernels or distorted ears (Figures 5,6).
 

Action

Figure 6. Shrunken and unfilled kernels may indicate BMSB damage. Photo courtesy Dr. Galen Dively, University of Maryland.
Table 1. Caption goes here
 Nitrogen
 Phosphorus
 Potassium
 12
 54
 43
 32
 65
 32
 43
 34
 12
 
 

The BMSB is very mobile and expected to be problematic again this year in corn and soybean fields.  Suspected insects or damage from BMSB can be brought to local county extension offices for identification.  Many insecticides, including pyrethroids, are effective against BMSB; however, spray equipment needs to be adjusted to allow for adequate coverage of the product.  Damage to crops may be most severe near tree lines, and field perimeter treatments may be used to temporarily stop a BMSB invasion.  Such treatments likely will limit the insect for a short time as adult BMSB can move in and out of fields as well as move farther into the field.  As adults, stink bugs are strong fliers and can fly to other fields.  Consequently, stink bug management can be challenging as they may fly toward more attractive feeding locations when reproductive stages begin in nearby fields.6