Brown Marmorated Stink Bug

Identification & Biology
Latin Name : Halyomorpha halys
Category : Insects & Spiders
Description :

Brown marmorated stink bug (BMSB) adults are shield-shaped, 13 – 17 mm long, brown marbled appearance, alternating brown and white markings on the outer edge of the abdomen.

Eggs are spherical, white or pale green, 1.6 x 1.3 mm; they are laid in clusters of 20 – 30 on the underside of leaves.

There are 5 immature (nymph) stages of BMSB. Nymphs range in size from 2.4 – 12 mm in length and do not have fully developed wings. Ist instar nymphs are bright orange to red in colour; 2nd instar nymphs are black, tick-like; later instars are pear-shaped, brown with white markings on abdomen and legs and white bands on last two antennal segments.

Look-a-likes: BMSB looks similar to several other bugs including rough stink bug, common brown stink bug and western conifer seed bug, can be distinguished from other stink bugs by the presence of distinctive white bands on the last two antennal segments.

Look Alikes
Habitat

Brown marmorated stink bug was first detected in British Columbia in 2015 and is present at low levels in urban areas of Fraser Valley and Vancouver, Brentwood Bay on Vancouver Island and the Okanagan Valley, as of October 2017. High numbers are present in the downtown Kelowna area.

BMSB attacks tree fruits, berries, grapes, vegetables and ornamental plants. Ornamental hosts include tree of heaven, chokecherry, catalpa, boxelder, white ash, maple, English holly, and buckthorn. In British Columbia, they have been found on Asian pears, vegetables and wild chokecherries.

Impact & Risks

It is a very serious pest that feeds on more than 100 different plant species. In 2010, an estimated loss of $37 million due to brown marmorated stink bug feeding was reported by the apple industry in the Mid-Atlantic States.

Both adults and nymphs feed by inserting their mouthparts into the flesh of fruit or vegetables. Feeding punctures result in small dead areas on fruit, vegetables and leaves. Brown marmorated stink bugs can be a contamination issue for grapes because the presence of a few adults at crush can taint wine.

The stink bug is an excellent hitchhiker and can be moved in shipping containers, wood, packing material, cargo and vehicles. It is also a nuisance to homeowners as the adults aggregate on and in buildings while seeking warm overwintering sites.

Prevention & Mitigation

Growers and homeowners are asked to send pictures or samples of suspect brown marmorated stink bug to the B.C. Ministry of Agriculture office in Kelowna.

Treatment & Disposal

Biological control: Trissolcus japonicus that attack the eggs of brown marmorated stink bugs in Asia have been found in the United States. Researchers in British Columbia are looking for the wasp. Other predators such as spiders, ladybugs and lacewings will feed on brown marmorated stink bug eggs.

Chemical control in commercial crops: the few registered insecticides for brown marmorated stink bug control in Canada provide only suppression of the pest.

Homeowners: Low numbers of brown marmorated stink bugs can be removed by hand, sweeping or a shop vacuum. Prevent entry into the home by sealing off any access points. The use of insecticides for controlling brown marmorated stink bugs in the home is not recommended.

Okanagan Distribution

Priority Level Definitions

Watch For - Poses a significant threat (very high risk) and does NOT presently occur in the region OR is relatively new to the region and is very limited in extent.
High - High risk/impact; limited population with significant potential to spread in the region.
Medium - Medium risk/impact; limited distribution – broader population distribution with potential to spread further in a region.
Low - Low risk/impact; may be widespread or not, may be of concern in specific situations with certain high values – e.g. specific agriculture crops. Some species may be treated primarily with biological control agents.