I've been having problems where whenever I prune one of my rose bushes, often one of the branches is burrowed into by a nasty cane borer, meaning I have to cut back the rose even further. I'm trying to control the problem by applying PVA to the exposed canes just after they're cut, but I'm worried this is bad for the rose.
Is there anything I can do to prevent these insects from attacking the plants? It has affected multiple bushes and killed off a gooseberry by now. I don't have photos of the damaged plants, as I've cut off the affected canes.