|Are they harmful to foliage? If so, how do I get rid of them?|
|Some stink bugs are benefical because they prey on other insects; others are destructive because they feed on plants. Home-garden sprays usually aren't effective because they need to make contact with the stinkbugs to kill them and these insects are very mobile and therefore hard to find.
Your first step is to control the stinkbug population by searching for and destroying egg masses on the undersides of the leaves, cleaning up the garden thoroughly in fall and removing any bushy growth, such as wild brambles, around the garden where adult stinkbugs overwinter. You may be able to reduce the pest population significantly by doing this. Inspect plants for the nymph or larval stages of the insect too. Pick these off and destroy, and/or spray frequently with insecticidal soap, making sure to cover the undersides of the leaves.
It is difficult to control the adults, so it's best to try to catch the pest when they are most vulnerable--as eggs and larvae. Pick off and destroy any adults you see feeding on your plants. Good luck with your garden.