Brown Marmorated Stink Bug

• In autumn it gathers in hundreds on sunlit house walls and squeezes through any gap to spend the winter indoors, where it does no damage but is a considerable nuisance.
• Its defensive smell comes from glands on the thorax and is so persistent that it taints fruit and can ruin an entire vintage if the bugs get into the press.
• Biological control is being trialled with an Asian wasp that parasitises its eggs, and which has already turned up in Europe and North America of its own accord.
• It was first detected outside Asia in Allentown, Pennsylvania, in 1996, although it was mistaken for a native bug until 2001; it is now in more than forty US states and across much of Europe.
• It feeds on more than 170 plant species, from 45 families.
• In 2010 it caused losses of more than 37 million dollars in apples alone in the Mid-Atlantic region, and of 60 to 90% of the peach crop in New Jersey.
• It enters houses en masse when the cold arrives, which makes it a domestic nuisance as well.
• It is being controlled with the samurai wasp, Trissolcus japonicus, which parasitises its eggs: in Trentino apple orchards parasitism rose from 8% in 2020 to 41% in 2023.

Skeleton type

Invertebrate - chitin exoskeleton (insect)

Habitat and environment

Fruit trees, crops and buildings in temperate regions

Size at birth

Smooth egg 1.3 mm across by 1.6 mm long; the first-instar nymph measures 2.4 mm and the fifth reaches 12 mm

Sexual maturity

The overwintering adults leave their shelter in early May, feed for about two weeks and then mate

Gestation / incubation

The eggs hatch in 3-7 days; after five nymphal instars development from egg to adult is completed in 40-60 days depending on temperature and day length

Litter / clutch size

Clutches of 20 to 30 eggs (28 on average) every 5-7 days on the underside of the leaves; 9 to 16 clutches over 2-3 months and 100 to 500 eggs in all, averaging about 240

Sources consulted: Wikipedia (es): Halyomorpha halys · StopBMSB.org (Lee et al. 2013, Medal et al. 2012-2013, Hoebeke & Carter 2003) · University of Georgia IPM, ficha BMSB · University of Minnesota · LSU AgCenter · University of Georgia IPM · LSU AgCenter, ficha Brown marmorated stink bug · Guias de manejo de Halyomorpha halys en Norteamerica · ficha CABI de Halyomorpha halys

Best time: Autumn, when it looks for somewhere to overwinter and comes into houses