Brown marmorated stink bug
The brown marmorated stink bug (Halyomorpha halys, or BMSB) is an invasive exotic insect native to Asia. It is known to settle first in urban areas, then move to other habitats. Discovered officially for the first time in North America in 2001, experts predict a rapid dispersal of this insect pest on the whole continent. The BMSB has been found in 44 states in the U.S., in 4 provinces in Canada and was recently confirmed in Montreal in 2016.
The BMSB can easily be confused with other native brown stink bugs. Nevertheless, it can be easily recognized:
- measures between 12 and 17 mm in length;
- brown marbled body is shaped like a shield;
- antennae and abdominal edge have alternating brown and white bands;
- margin of the shoulder (thorax) is smooth.
Damage to plants
The BMSB insert their piercing-sucking mouthparts into the plant tissues and remove the sap. Digestive enzymes are then inserted into the plant, resulting in the formation of necrotic areas at the feeding site. All plant parts (fruits, stems, leaves or buds) can be targeted.
This exotic pest can attack hundreds of plant species, including several fruit crops (apple, pear, cherry, lemon, apricot, raspberry and blackberry), vegetables (beans, tomatoes, sweet corn, peppers, etc.), ornamental plants (maple, elm, lilac, hibiscus, etc.). It can cause significant damage to a wide variety of crops where it is already established.
Nuisance in homes
The BMSB can be a nuisance in urban areas. It has a tendency to enter heated buildings during fall to spend the winter.
The BMSB is not a danger to human or animal health. It does not bite nor reproduces inside the buildings. Stink bugs only attack plants. They release an unpleasant odor from scent glands located on their abdomen when they are disturbed or squashed.
Mechanical exclusion is the best method to keep them from entering structures. For example:
- seal all cracks;
- repair or replace damaged screens;
- remove or cover window-mounted air conditioners prior to autumn.
Stink bugs that have made their way into your home can be removed with a vacuum cleaner. It is important to empty or dispose of vacuum bags quickly because the smell will persist. It is also possible to make a homemade trap with a plastic bottle to catch the insects. Slide the trap under the insects so that they fall inside the container. Then place the captured insects in an airtight plastic bag.
You can get rid of captured insects by placing them in the freezer for a few days or by drowning them in soapy water. Dead insects can be thrown in the trash or in compost. Do not put them in the toilet. You would waste water unnecessarily!
BMSB Monitoring Project
Observations have increased, particularly in the Montreal area. In Quebec province, the BMSB is monitored since 2014 with a network of traps deployed in different urban and rural areas. The first captures in Montreal were made in 2016. Several spontaneous reports were also made by citizens in 2017, and 2018 and 2019. It is therefore important to characterize the BMSB invasion in the territory in order to better predict the extent of the phenomenon and its consequences.
Since 2017, the City of Montreal has been collaborating with Agriculture and Agri-Food Canada (AAFC) and the Ministry of Agriculture, Fisheries and Food (MAPAQ) in the BMSB monitoring network. The Ecological Transition and Resilience Office (Bureau de la transition écologique et de la résilience, BTER) is coordinating the efforts to detect and identify this pest insect on the island of Montreal. This project aims to detect where the insect is present on the agglomeration territory. Traps are deployed on both public and private lands. The traps are checked on a weekly basis throughout the summer until the end of October by municipal employees. The results are shared with the monitoring network partners.
In past years, several BMSB specimens were captured and observed (adults, nymphs, eggs). The monitoring results, and the spontaneous reports made by the citizens, show that the insect is now well established on the island of Montreal. This project highlights the relevance of involving a city in the early surveillance of insect pests. The proportion of reports spontaneously made by citizens illustrates the great potential of citizen science, an aspect that could be further developed in the coming years.