The brown marmorated stink bug could be a huge problem for fruit growers in California and especially bad for a few specific crops like wine grapes.
We now know that the brown marmorated stink bug (BMSB) is spreading down California from the northern part of the state. Cal Poly professor David Headrick says we have learned a lot from the pest’s history in other states and some producers in particular should be concerned. He says Napa area wine makers could be the first to see a major problem with the pest as a single stink bug could ruin grape crush.
More about Brown Marmorated Stink Bug
From the UC Integrated Pest Management website: The adult BMSB is a typically-shaped stink bug, about 5/8 inch long, and marbled brown. It can be distinguished from other stink bugs of comparable size and color by the following characteristics: the antennae have two white bands; the forward edge of the head is blunt; the margin of the shoulder (thorax) is smooth; the legs are marbled brown with faint white bands; the membranous parts of the forewings have dark bands at the tip; and a banded abdominal edge is visible to the side of the wings. BMSB is commonly mistaken for other stink bugs, especially the rough stink bug, Brochymena sulcata, due to its similar size and brownish color. The rough stink bug has a rough shoulder margin, the forward edge of the head is extended with two points, and there are no white bands on the antennae, although there are tiny light-colored striations where the antennae segments join. The consperse stink bug, Euschistus conspersus, has banded abdomen edges like BMSB but no bands on its antennae, and the legs have distinct dark spots rather than marbled markings and white bands; it is also a little smaller with a length of about 1/2 inch.
Eggs are barrel shaped, white to pale green, and laid in clusters on leaves. Nymphs shed their outer skin (molt) as they progress through five stages or nymphal instars before becoming adults. Nymphs range in size from 2.4 mm (first instar) to 12 mm (fifth instar). The newly hatched nymph has an orange abdomen with dark brown plates and brown head and thorax. First instars remain clustered around the egg cases feeding from the egg before dispersing, sometimes remaining until they molt to the second instar. The newly-molted second instar has an almost black appearance; subsequent instars (third through fifth) have marbled brown head and thorax and reddish brown, black, and white abdomen markings. They have distinct white bands on the antennae and legs and spines in front of red eyes and on shoulder edges. Fourth and fifth instars have visible wing pads. Read more here.