Brown marmorated stink bug damage

As a polyphagous pest, the brown marmorated stink bug has the potential to cause damage to several crops, including tree fruit, nuts, vegetables and row crops. On tree fruits, feeding injury causes depressed or sunken areas that may become cat-faced as fruit develops. Late season injury causes corky spots on the fruit. Feeding may also cause fruiting structures to abort prematurely. Similar damage occurs in fruiting vegetables such as tomatoes and peppers, although frequently later in the season. Feeding can cause failure of seeds to develop in crops such as maize or soybean. There is frequently a distinct edge effect in crop plots as H. halys has an aggregated dispersion and moves between crops or woodlots.

Life cycle of the brown marmorated stink bug

Halyomorpha halys goes through five nymphal instars. Eggs are laid in clusters of approximately 28 on the under surface of leaves. Newly laid eggs are about 1.3 mm in diameter and 1.6 mm in length and light green or light blue. As the embryo develops it may become visible through the egg, with the eyes appearing as two red spots.

The first instar nymphs are approximately 2.4 mm in length, with a black head and thorax and an orange-red abdomen. First instars, aggregate around the empty eggs. The possible advantages of aggregating in this manner are increased protection from drought and high temperatures, and increased protection from natural enemies by pooling their chemical defences. Following the transition to second instar, the nymphs lose a majority of their orange-red colouring. Second instar nymphs appear dark, with rough spiny projections along the lateral edge of the thorax. Wing buds begin to develop with each successive molt. Later instars have a black to grey base coloration with noticeable spines along the humeral (shoulder) margins, as well as white bands on the legs and antennae.

Adults of the brown marmorated stink bug are from 12 to 17 mm in length. The base colour is a mixture of brown, dark red and black on the dorsal surface, with a beige or cream-colored ventral surface punctuated with metallic green markings on the ventral thorax. Key features for identification of the adult include white bands on antennae and legs, no humeral (shoulder) spines, and alternating dark and light bands on the margin of the abdomen.