Brown marmorated stink bug
The marbled tree bug belongs to the family of tree bugs (Pentatomidae). It is about 15 mm in size, brown-gray marbled in color with conspicuous black and white patterned lateral margins on the abdomen and with black and white striped antennae. There is no appendage between the legs on the underside of the body.
Possibilities of confusion
Confusion with native species is possible, e.g. with the following species:
- Berry bug(Dolycoris baccarum)
- Holcostethus (= Peribalus) strictus
- Gray garden bug(Rhaphigaster nebulosa)
However, the marbled tree bug can be clearly distinguished from the gray garden bug by some characteristics (e.g. no elongated process on the underside of the body between the legs, bright spots behind the neck shield, stripes in the transparent part of the wings).
The adult bugs become active in spring at temperatures above 10 °C and search for suitable host plants, where they feed on plant sap. After several weeks of sucking activity, the females begin laying eggs, which continues into late summer. Their egg clutches (groups of 20 to 30 eggs) are located on the underside of leaves, and a female can lay an average of more than 200 eggs, with a maximum of about 450 eggs. After only a few days, the larvae (nymphs) hatch and like to stay in groups on the plants. After five nymphal stages, they molt into adult bugs. The development from egg to adult bug takes about one and a half to two months. The bugs suck mainly on fruits, but also on leaves. In the fall they leave their host plants and look for overwintering quarters, where they like to gather in larger numbers in sunny places, such as house facades and windows, where they can become a nuisance to humans, but completely harmless. They overwinter as adults in protected areas, such as garden sheds and houses.
In their original habitat (Asia), five to six generations develop per year; in Europe, only one to two generations (in warmer areas) are expected.
The marbled tree bugs sting leaves and fruits with their proboscis to suck the plant sap. In the process, a protein (enzyme) enters the plant tissue with the saliva, causing stains and necroses, which can later discolor and deform the fruit. Not only do the fruits become unsightly and no longer marketable, but the infested plant parts may also die or fall off prematurely.
These symptoms are often not clearly attributable to the marmorated tree bug, because other sucking insects, e.g. soft bugs (Miridae), cause similar damage.
The marbled tree bug is a very polyphagous species of bug that can use more than 100 different plant species as host plants. Mainly it sucks on fruit crops, but also on ornamental trees and shrubs as well as forest trees, plants of vegetable and arable crops and herbaceous plants. It prefers species of the rose family (Rosaceae), such as apple, pear, cherry, peach, nectarine, raspberry, and citrus. Common host plants are also found among ornamental shrubs, such as summer lilac(Buddleia davidii), bluebell tree(Paulownia tomentosa), and trumpet tree(Catalpa bignonioides). Peppers and tomatoes are among the preferred host plants among vegetable crops.
The original natural distribution of the marbled tree bug is in eastern Asia (eastern China, Taiwan, Korea, Japan). From there it was probably introduced with transport crates to North America in 2001, but was probably already present since 1996, and then spread very rapidly and massively. In Europe, it was first detected in Liechtenstein (2004) and then in Switzerland (2007); it is now already found in many European countries. In Austria, the first specimens of the marmorated tree bug were discovered in Vienna and in Dornbirn (Vorarlberg) in 2015; since autumn 2016, the marmorated tree bug was frequently seen on and in houses in Vienna, where it was looking for overwintering sites.
Prevention and control
International studies and experiences on the control of the marbled tree bug, such as with different types of traps, "attract & kill" methods and also mechanical barriers (e.g. netting, sticky tapes around tree trunks) and broad-spectrum plant protection products, have so far shown only partial control success. In Austria, no plant protection product is currently registered for control specifically against the marbled tree bug, but against tree bugs in general (see List of plant protection products registered in Austria).
In China, there are several species among the chalcid wasps (Chalcidoidea) that parasitize eggs of Halyomorpha halys. Representatives of Trissolcus spp. and Anastatus spp. can achieve very high parasitization rates (up to 85%). Various research efforts are currently underway on the influence of native natural counterparts (parasitoids, predatory insects and spiders) in Europe against the marbled tree bug and the potential use of non-native chalcid wasps for biological control.
If suspicious bugs are found (similar in appearance to Marbled Tree Bug), they can be sent to us for clarification of species or identification, but prior contact is encouraged.
We conduct ongoing surveys on the occurrence of various introduced organisms. Within the framework of the international EUPHRESCO project EPIDISARTH, which started in 2021, the distribution of the marmorated tree bug in Austria is surveyed.
Lethmayer, C., 2017. halyomorpha halys - spread in Austria. Better Fruit 12(6).
Last updated: 12.07.2022