New Stink Bug Found in Missouri Soybean

Published: December 8, 2009

Dr. Kelly Tindall, field crop research entomologist located at Delta Research Center, Portageville, reported Red Banded Stink Bugs (Piezodorus guildinii) were found in soybean fields from Dunklin County Missouri. She believes this insect may initially become a significant pest of soybean grown in Southeast Missouri in 2010 and possibly cause problems in soybean statewide in future years. During October, Dr. Tindall surveyed 14 soybean fields in Dunklin and Pemiscot counties and found red banded stink bugs in 3 fields. Although low in number at this time (5.4% of total stink bug species captured), they possess the ability to rapidly increase in number and pose a threat to soybean in future years. The red banded stink bug is a major pest of soybean in most states south of Missouri and in South and Central America.

Figure 1. Redbanded Stink Bug. (courtesy of Russ Ottens, University of Georgia, Bugwood.org)

At present the common stink bug species currently inhabiting Missouri soybean fields include the green stink bug (Acrosternum hilare), Southern green stink bug (Nezara viridula) , and two brown stink bug species, the brown stink bug (Euschistus servus) and the one spotted stink bug (Euschistus variolarius). In general, the green stink bug feeds mainly on soybean with heavy feeding resulting in "delayed senescence" of the soybean in some fields. In contrast, the two brown stink bug species tend to feed on seedling through silking stage corn plants, although they sometimes can be collected in high numbers from soybean during the fall of the year. The Southern green stink bug, along with an additional species named the red shouldered stink bug (Thyanta sp.) are primarily found on soybean in Missouri counties close to Arkansas. All stink bugs use their "piercing/sucking" type of mouthparts to feed on plant juices. Most attack soybean stems, foliage, and more importantly pods when feeding.

The red banded stink bug adult is green in color although it yellows with age. It has a predominant red, and less predominant black, and yellow bands running across the back of the pronotum. A total of five nymphal or immature stages are produced and appear as small versions of the adult in shape, but vary in color with more red or yellow coloration present. Each adult female will lay approximately 15 black eggs that are positions in two joined lines to produce a sting of eggs. This is in contrast to most other common stink bug species which lay egg in clumps or masses.

The movement of the red banded stink bug into Southeast Missouri soybean fields will most likely alter the existing composition of stink bugs in soybean. In Louisiana where the red banded has been a major problem for the past 5-7 years, it now is the most prevalent (70%) and most important stink bug present. It also is the most difficult to control with insecticides as compared to green stink bug being easiest and brown stink bug species intermediate in ability to control. The red banded stink bug may cause significant economic damage to soybean pods, especially in late planted beans. In several studies conducted at the Louisiana State Agriculture Center, soybeans yields were reduced by an average of 43% when left untreated as compared to treated plots which typically required four insecticide applications to suppress red banded numbers to below economic threshold levels. In studies conducted at the LSU AgCenter, red banded stink bugs damaged an average of 41% of soybean seeds resulting in about a 30% reduction in seed weight when insects were caged on soybean for a period of 72 hours.

Our concern with this insect comes from the fact that it is a rapid disperser as observed in Arkansas where it movedthrough the state in about three to four years. It also is more difficult to control with insecticides than most other stink bugs which will allow it to more rapidly become the predominant stink bug pest in Missouri soybean fields. On the other hand, the more northern climate found in Missouri may slow or restrict the movement of this pest into central and northern areas of the state. An extensive monitoring program for this pest in Missouri will be implemented in 2010 in order to track any movement of this pest further into the state.