General information

The Brown Marmorated Stink Bug (Halyomorpha halys) is an invasive species from Asia (China, Taiwan, Japan, Korea). It was accidentally introduced to other countries in the early 1990s. In the western part of the United States, above all, an increase in the spread and reproduction of this invasive insect has led to the loss of a range of crops, above all apple, peach, soy and corn, from 2010 onwards. In Europe, H. halys first appeared in Switzerland and Liechtenstein in 2004. It feeds on a large number of plants, on which it also reproduces. More than two hundred plant species have been recognised all over the world as falling within the diet of H. halys and also suitable as breeding sites for the insect.

This news provides  more information about the BMSB.

Biological control

Introduction to Trissolcus japonicus to control Halyomorpha halys

Classic biological control, releasing native antagonists in the area of the plant eater has been seen as the most suitable approach in taking control of H. halys once introduced into newly invaded areas. Trissolcus japonicus, also known as the samurai wasp, has been identified as the most promising means of biocontrol, considering its specificity and high level of parasitism. Adventitious populations of T. japonicus have been recorded in Europe since 2017.

Italy is the first country to implement a programme with all the key characteristics of biocontrol initiatives: importation of T. japonicus into quarantine facilities for the assessment of the parasitoid’s range of action; obtaining approval for the issue by competent authorities (Ministries of Agriculture and the Environment and the Superior Institute of Health); experimental breeding of the biocontrol agent; inoculation of individuals in the new area so that their numbers can increase autonomously in response to the stink bug populations.

Activity and results

Since 2020, the Province of Bolzano has been part of the three-year programme to release T. japonicus, also continuing through 2023. There have been three releases in each season, in over forty sites, located in the main valleys of the province. In 2023, releases took place in just ten sites. During the four-year period of the experiment, monitoring was constant to assess the reproductive capacity, spread and effectiveness of T. japonicus against the Brown Marmorated Stink Bug, with a specific focus on the unwanted effects on non-target organisms, in particular, the possible parasitisation of T.japonicus on native stink bugs. The parasitisation of T. japonicus on H. halys has increased over the years, starting with 34.1% in 2020 to arrive at 65.7% in 2023. T. japonicus has been the main H. halys parasitoid since 2021. The ability to pass the winter and settle in the area were assessed in the pre-release period, in locations chosen outside the release sites. Several years of monitoring have shown how the parasitoid is able to pass the winter and to settle in different areas at local level.

Links to websites for more information

• Brown Marmorated Stink Bug: the spread of natural antagonists in South Tyrol: https://bia.unibz.it/esploro/outputs/journalArticle/Cimice-asiatica-la-diffusione-degli-antagonisti/991006484974401241
• Evidence of Trissolcus japonicus settlement in South Tyrol: https://bia.unibz.it/esploro/outputs/journalArticle/Evidenze-di-insediamento-di-Trissolcus-japonicus/991006484842901241
• Biological control of H. halys: report on three years of releasing the antagonist Trissolcus japonicus: https://bia.unibz.it/esploro/outputs/journalArticle/Lotta-biologica-alla-cimice-asiatica-bilancio/991006590593701241
• Factors influencing short-term parasitoid establishment and efficacy for the biological control of Halyomorpha halys with the samurai wasp Trissolcus japonicus: https://scijournals.onlinelibrary.wiley.com/doi/10.1002/ps.7423
• Assessing the Distribution of Exotic Egg Parasitoids of Halyomorpha halys in Europe with a Large-Scale Monitoring Programme: https://www.mdpi.com/2075-4450/12/4/316
• An Insight into the Role of Trissolcus mitsukurii as Biological Control Agent of Halyomorpha halys in Northeastern Italy: https://www.mdpi.com/2075-4450/11/5/306
• Assemblage of the Egg Parasitoids of the Invasive Stink Bug Halyomorpha halys: Insights on Plant Host Associations: https://www.mdpi.com/2075-4450/11/9/588