Would this product be good to kill the Viburnum Beetle. I have read many different articles on this bug that say there is no way to kill it. I have a snowball bush that has been brutilized by this bug.
I'm not sure if DE will kill it, but as to what eats and will naturally control viburnum beetle, apparently lady beetle, lacewings and spined soldier bugs (mostly larvae) feed on this beetle and can naturally control it:
So I would try to find ways to draw more beneficial insects to your bush, if at all possible.