Pruning Infested Limbs
Because partly grown borer worms often pass the winter in the stems of shrubs or trees, cutting off infested branches destroys them and limits their damage before they resume feeding in the spring. Look for branches showing swollen areas with cracked bark that has broken away from the wood. Small holes, with or without the telltale sawdust, may be visible. With a pruning saw or loppers cut off the affected branch back to healthy wood nearer the main trunk or crown of the plant.
If the whole top of a tree is infected or borers are in a main trunk or stem of a large tree, then pruning is probably not appropriate and other control methods must be used. Consult a trained arborist for advice and assistance.
Flexible Wire Trick
It is possible to kill borers by inserting a flexible wire into their tunnels. The wire approach works only in situations where there are only one or two borers in accessible places and the borer holes are fairly straight and shallow. With a hooked wire, it may be possible to catch the worms and pull them out. Otherwise, use the wire tip to mash the worm. Do this in March or April and again in August or September. Take some care using the wire to avoid extra damage to the tree or shrub.