Marmorated stink bugs
In the home garden, pears, both Asian and European, are among the prime tree fruit targets of brown marmorated stink bugs (BMSB, the technical name Halyomorpha halys). Other frequent targets include apples, nectarines and peaches.
Few cultural and mechanical methods exist for managing Brown Marmorated Stink Bugs (BMSB) in the home garden. Unfortunately, there’s no way to get rid of them. Gardens adjacent to wooded areas are typically among the most severely damaged.
No single resource lists all management options, so consider this a sampler of what you can try. Most likely, a combination will be wise.
Destroy egg clusters when seen and flick the insects into slightly soapy water. A spray of kaolin clay (Surround-at-Home) can reduce fruit damage when thorough coverage is applied but realize that the tree will appear as if coated with dust.
Exclusion by protecting the planting with floating row cover is advised with vegetables. This might work for pears if you can rig a protective “sleeve” for individual branches. Then, too, some folks bag individual fruits such as is done against codling moth.
No effective pesticides are available for home use against BMSB. Even so, the active ingredient azadirachtin (neem extract) may be useful to help limit populations as it is suggested for use against other, less damaging stink bugs. Then, too, insecticidal soap, sold under various brand names, may also limit activity, but only if the spray contacts the insects.
In general, insecticides are more likely to be useful against the nymphs (youngsters) than against the adults. Follow label directions for dilution rate and frequency of use.
“Brown marmorated stink bugs” contains images of various life stages as well as detailed information. (http://entnemdept.ufl.edu/creatures/veg/bean/brown_marmorated_stink_bug.htm) Notice that the antennae of every life stage, from the youngest to the oldest, are marked with white bands.
Thank you Jean. It sounds like it is going to be a battle. Doug
Yes, it will. But there's hope. I've received anecdotal reports from previous clients that their BMSB population declined through the next several years.