So, what's the problem
The brown marmorated stink bug, Halyomorpha halys (Stal) (Hemiptera: Pentatomidae), is native to China, Japan, Taiwan and Korea and is invasive in the US, Canada and Switzerland. Due to its extremely wide host range it is a serious pest of many fruit trees, shrubs, ornamentals, fruit and vegetable crops.
In North America it was first detected in 1996 in Allentown, Pennsylvania, and is now present in 38 states in the USA. The stink bug quickly became a major nuisance pest in the mid-Atlantic USA region due to its overwintering behaviour (where it enters houses and other manmade structures). In Canada H. halys was first reported in Vancouver where it was found in goods imported from Japan in 1993. In 2010, some of these intercepted specimens were also reported in Ontario and Quebec. In 2012, the first breeding population was found in Hamilton, where the stink bug now seems well established. Its discovery immediately raised concern among Canadian fruit growers because H. halys previously caused severe losses in fruit production in the Mid-Atlantic States of the US (in 2010). It is expected that H. halys will spread further throughout Canada and become a serious threat to Canadian fruit production in the next few years causing potential economic impacts on other crops including sweet corn and soybean.
In the US, control of H. halys is only currently through broad-spectrum chemical insecticides, but research is being conducted to use natural enemies from Asia, which are thought to be important in mortality. In China, parasitoid wasps in the genera Trissolcus and Anastatus cause high levels of egg parasitism. Among these, Trissolcus halyomorphae (Hymenoptera: Scelionidae) is the most promising candidate for biological control of brown marmorated stink bug in North America.
What is this project doing?
The objectives of the study are to determine the natural enemy complex of H. halys and non-target stink bugs in Asia and the extent of the field host range of candidate biological control agents. The purpose is to develop host range and non-target information that will allow future investigations on the ecological host range of Trissolcus halyomorphae and other possible candidate biological control agents of H. halys in China. This work will supplement both field and laboratory studies being done in Canada, and will allow Agriculture and Agri-Food Canada scientists and Canadian Food Inspection Agency regulators to assess the risk to native stink bugs species presented by the importation of these exotic parasitoids to North America. The results may also support the importation of additional parasitoids of H. halys – selected for their performance in Canada.
Field surveys have been conducted in the two Chinese provinces – Beijing and Hebei – to assess egg parasitism of different Pentatomid species (stink bugs) co-occurring with Halyomorpha halys. In both provinces several field sites were visited, including fruit orchards, botanical gardens and natural sites.
In total, six pentatomid species were found during the field surveys, e.g. Halyomorpha halys, Dolycoris baccarum, Plautia sp., Eurydema sp., Stollia sp. Erthresina fullo. Field collected egg masses of H. halys were heavily parasitized by Trissolcus halyomorphae and Anastatus sp., whereas non-target species were attacked by five different egg parasitoids from the genera Trissolcus, Anastatus, Ooencyrtus and Telenomus.
Investigations on the ecological host range of T. halyomorphae in China will be continued. In addition, we will monitor the spread of H. halys in Switzerland and investigate whether native European egg parasitoids have the potential to control the invasive stink bug.