The Brown Marmorated Stink Bug first appeared in the Mid-Atlantic Region around 1994 and was primarily considered an urban nuisance as it is fond of wintering over in your home. By 2010, it was causing $37 million annually in damage to the Region’s apple crop. It is not an apple pest management issue exclusively ; it also likes small fruits (blueberries and other cane fruits), ornamental plantings, vegetables, grapes, and other orchard crops.
The Northeastern IPM Center provides a broad review on the insect, what is known, and the ongoing research. Oregon State University is researching the possibility of using a tiny parasitic wasp, also from China, that lays their eggs in the Stink Bug’s eggs. However because the environmental impact from releasing another non-native wasp species into the wild is unknown they are keeping these wasps in quarantine. Not all Stink Bug species are bad and the ideal solution is finding a predator that attacks the Brown Marmorated Stink Bug exclusively. These pests are harmless in the house but are very detrimental to crops.
I have found them mostly on my Rosa Rugosa but as the blackberries and raspberries are beginning to flower and will set fruit soon, as I already have fruit set on my cherries, currants and blueberries, I will be a little more diligent in patrolling the yard this summer. They are easily confused with the Brown Stink Bug which is more of a problem for corn and soybean but also can damage fruit crops.
Good luck, stomp them out if you get a chance. Check underneath leaves where you have seen them and destroy any egg nests encountered.