Stink Bug Alert!

Hannah Fraser, Entomologist – Horticulture, OMAFRA – Guelph

Vegetable and fruit growers should be on the look-out for signs of stink bugs in their fields and orchards. In the last few weeks, we have visited apple orchards in Niagara with fruit showing damage that is characteristic of stink bugs (Figures 1-4). Early injury is easy to overlook (Figures 5 & 6). We have also seen injury in tomatoes (Figure 7-8).

Figure 1. Two apples, both with stink bug injury. The apple on the right has multiple feeding sites and appears irregular.

Figure 2. Magnification may be required to see the small feeding puncture.

Figure 3. Corking appears immediately under the skin with stink bug injury, versus cork spot (not shown), which may be either circular or diffuse and may be separated from the skin by “healthy” flesh.

Figure 4. Sometimes injury can be hard to diagnose. Closer examination of this apple indicated the injury was likely stink bug.

Figure 5. Recent injury to apple (Photo courtesy of Matt Peters)

Figure 6. Recent injury to apple, multiple stings (Photo courtesy of Matt Peters)

These insects are mobile and can be frustratingly difficult to find during scouting activities. Traps are available for monitoring purposes. These can be useful for early detection, and potentially for action thresholds. Depending on the lure type, they will trap brown marmorated stink bug (BMSB) (Figure 8) and other species.
In the absence of insect samples, we do not know if BMSB is causing the injury, or if it is another species of stink bug. However, BMSB is established in Niagara and other parts of southern Ontario, and it should be added to monitoring / pest management programs. There is some excellent information on managing BMSB in apples and other crops on the stopBMSB.org website: http://www.stopbmsb.org/where-is-bmsb/crop-by-crop/. Note that the products and / or rates we have registered differ from those listed, see http://www.omafra.gov.on.ca/english/crops/insects/bmsb-registrations.htm. Recommendations are provisional and will change as more information about BMSB becomes available.

We are seeing mostly adults at this point in the season. Some of these are starting their movement to overwintering sites, but many are still out there looking for things to feed on. They will likely be active for a few more weeks. As a late-season crop, apples and are at high risk, along with pears, corn, peppers, tomatoes, and grapes. Pest pressure is often highest along border areas, especially woody areas with wild hosts.

If you think you have found stink bug injury, or if you have found BMSB in your crop, please drop off a sample of the insect and associated damage at your local OMAFRA office. BMSB is new to Ontario and we are still learning about its potential impact in crops.

Further information:

Pest monitoring equipment suppliers

Integrated pest management for brown marmorated stink bug in vegetables

Stink bugs in tomatoes