Stink bugs killing Monarch Butterfly caterpillars

Asked August 20, 2015, 7:28 PM EDT

Help!! I have found numerous monarch caterpillars being killed by stink bugs in my swamp milkweed. Both small and large caterpillars, I have found a stink bug firmly attached and sucking them dry. What can I do?

Centre County Pennsylvania

1 Response

I see quite a bit of research online regarding monarch caterpillar predation by a number of animals including birds, wasps, flies, assassin bugs, and stinkbugs. There are a number of Hemiptera (the order to which stinkbugs and assassin bugs belong) that are generalist predators in the the food web. To my knowledge, you will not be able to apply any kind of pesticide, insecticide in this case, to kill only the predatory stinkbugs and not harm your monarchs or other beneficial insects. Handpicking of the stinkbugs or caging off your milkweed looks to be two of your best management options.