Adult Description: Brown marmorated stink bugs (Halyomorpha halys) have a shield shaped body characteristic of all stink bugs. The adults are approximately 15-17 mm long with a mottled brownish grey color. The (4th) antennal segment has a white band. Several abdominal segments protrude from beneath the wings and are alternatively banded black and white. The underside is white, sometimes with grey or black markings, and the legs are brown with faint white banding.
Larva Description: The white or pale green barrel-shaped eggs are laid in clusters on the underside of leaves. Egg masses contain about 25 eggs that are about 1 mm in diameter but become apparent when nymphs have recently emerged, as they will stay at the egg mass for several days. In Pennsylvania, eggs first appeared in late June, but females continued to lay egg masses until September.
Host Plant: Many agriculturally-important plants, from apples to soybeans. Also, various ornamental plants are at risk.
Ecological Threat: Similar to other stink bugs, the nymphs and adults have a piercing-sucking mouthparts. Stink bugs use these mouthparts in a straw-like fashion by piercing the fruit. Small necrotic spots on fruit and leaf surfaces often result from feeding damage, and it may be compounded by secondary infections and scarring as the fruit matures. In particular, affected apples often exhibit pitting and discoloration and peaches frequently display a characteristic distortion referred to as "catfacing". Even if the fruit is still edible, it may not be suitable for market. Similar damage to other crops, such as soybeans, is more likely to occur in the southern U.S. Because the brown marmorated stink bug is polyphagous, or feeding on a wide range of host plants, almost any crop with fruit may be at risk.
Biology: Although the first specimen was positively identified in 2001, there were numerous reports of a nuisance stink bug in Allentown, Pennsylvania several years prior to that date. Interviews with homeowners indicated that there were likely breeding populations in Allentown as early as 1996, and the brown marmorated stink bug has been reported in 34 Pennsylvania counties as of 2011. The brown marmorated stink bug has been reported, detected, and/or intercepted in several U.S. states, including Virginia, Maryland, North Carolina, Delaware, and New Jersey. The pest could potentially be more destructive as it invades southern states.
The brown marmorated stink bug is a strong flier and a highly mobile pest which can move from host to host during the growing season (e.g. from early to late-reopening fruits). Over long distances the pest can be disseminated by trade of host plants, but also by movement of goods or vehicles. For example, in California it is suspected that the first brown marmorated stink bugs were introduced with household items as they were found on a property whose owner had recently moved from Pennsylvania. Until now, the pathways of introduction of the brown marmorated stink ug into the U.S. or Switzerland remain unknown but it is suspected that this pest was introduced either as a hitchhiker on packing material or via plant imports.
History: The brown marmorated stink bug, is a pest that was first officially reported from the western hemisphere in Allentown, Pennsylvania in 2001. This stink bug may become a major agricultural pest in North America, similar to the southern green stink bug, Nezara viridula. Both species are polyphagous pests of various crops, but in the U.S. it has been primarily reported as a household nuisance and ornamental pest. However, in eastern Asia where the brown marmorated stink bug is native or indigenous, it is a pest on fruit trees and soybeans.
U.S. Habitat: The brown marmorated stink bugs are often found on or around its desired host plant, using its mouthparts to suck juices from the plant.
Native Origin: Asia, specifically China, Japan, Korea and Taiwan.
U.S. Present: CA, DE, DC, FL, GA, IN, MD, MA, MI, NJ, NY, NC, OR, PA, TN, VA, WV
The Brown marmorated was found in Corpus Christi located on an RV that had traveled from PA in October. It is hypothesized that this insect will thrive in warmer climates and continue to be transported via travelers who winter in Texas, specifically in the Rio Grande Valley.
The southern green stink bug, Nezara viridula, another invasive species, is often mistaken for the Brown marmorated stink bug.
Pesticide is the most-commonly used method of management for the Brown marmorated stink bug. However, a newly described species, Trissolcus halymorphae Yang (Hymenoptera: Scelionidae) is an egg parasitoid that has been identified as the primary biological control agent responsible for the management of Brown marmorated stink bug in northern China. This parasitoid averages a 50% mortality rate for Brown marmorated stink bug populations, and it was the only natural enemy identified with a mortality rate exceeding 10%. Trissolcus halymorphae is currently not known to occur in the U.S. with existing populations of brown marmorated stink bug. Future management of brown marmorated stink bug populations in orchards or other commodity-based fields will probably consist of a combination of integration of reduced-risk pesticides and biological control.
Khrimian A, Shearer PW, Zhang A, Hamilton GC, Aldrich JR. 2008. Field trapping of the invasive brown marmorated stink bug, Halyomorpha halys, with geometric isomers of methyl 2,4,6-Decatrienoate. Journal of Agricultural and Food Chemicals 56: 197-203.
Nielsen AL, Hamilton GC. 2009. Seasonal occurance and impact of Halyomorpha halys (Hemiptera: Pentatomidae) in tree fruit. Journal of Economic Entomology 102: 113-1140.
Nielsen AL, Shearer PW, Hamilton GC. 2008. Toxicity of insecticides to Halyomorpha halys (Hemiptera: Pentatomidae) using glass-vial bioassays. Journal of Economic Entomology 101: 1439-1442.
Yang Z, Yao Y, Oiu L, Li Z. 2009. A new species of Trissolcus (Hymenoptera: Scelionidae) parasitizing eggs of Halyomorpha halys (Heteroptera: Pentatomidae) in China with comments on its biology. Annals of the Entomological Society of America 102: 39-47.
Mike Merchant - Texas A&M University - firstname.lastname@example.org