BMSB Update - May 16, 2014

Based on a new batch of confirmed homeowner finds in the Windsor area and around London, it appears that the brown marmorated stink bug (BMSB, Figure 1) may be established across southwestern Ontario. We need to follow-up with field surveys in these areas to confirm. Growers and their scouts should be on the look-out for this pest as the season progresses, so they are not surprised by any finds in crops.

BMSB found resting on the side of a house

Figure 1. BMSB found resting on the side of a house

For those that were hoping a cold winter killed off most BMSB, think again. Even if mortality under the bark of dead standing trees (where they would naturally overwinter) is higher than normal, the shelter-seeking behaviour of this pest means individuals overwintering in attics and under siding were protected from temperature extremes and will live to see another spring.

Increasing daylight and warmer temperatures seem to be prompting BMSB to vacate their overwintering hideouts, resulting in an increasing number of homeowner finds over the last month or so. A few adults have been collected outside on the side of a building in Hamilton over the last few days (early May), indicating they will soon move onto whatever nearby landscape vegetation suits their taste.

Should you worry about BMSB in your crops at this point in the season? No, not yet. Most BMSB are still moving out of their overwintering sites. Once they make their way into the landscape (usually onto trees and shrubs near buildings), it takes several weeks for the adults to become sexually mature and to begin laying eggs. Crops are at higher risk once the eggs start to hatch, after which both adults and nymphs contribute to feeding damage. In more southerly regions such as New Jersey, this typically occurs in early- to mid-June.

The most important advice is to monitor for BMSB in crops and on preferred wild hosts (examples "tree of heaven", buckthorn; see list at in adjacent landscapes / woodlots, keeping in mind this insect is highly mobile and can move into crops from adjacent natural reservoirs at any point in the season. Stay tuned for more information on scouting and management.

If you think you have found BMSB, please let us know. Collect your suspect bug(s), take some good quality digital pictures, and get in touch with the Agriculture Information Contact Centre at or 1-877-424-1300.

Locations with confirmed established populations: Hamilton / Burlington, Newboro.

Locations with confirmed homeowner finds: Windsor-Essex, Kincardine, Cedar Springs, London, Paris, Stoney Creek, Niagara Falls (image only), Fort Erie, St. Catharines (image only), Niagara-on-the-Lake, Milton, Vaughan, Toronto, Ottawa.

For more information:
Toll Free: 1-877-424-1300