Cane borers cause damage to the cane regardless of the species of the
critter. Many will carry disease into the cane that will cause further
damage to the plant. The bored cane will normally die back, the rate
depends on the bore damage and what if any fungal disease was carried into
the bore hole. If the damage is sufficient it can potentialy kill the
plant.

Many people 'seal' the canes immediately after they are cut. This tactic
usually doesn't work well because the cut will ooze for a day or so and
prevents most of the sealant from adhering to the end of the cane. A
better, albiet more labor intensive approach is to wait at least 24 hours to
allow the cut to 'dry' and then apply a sealant. This obviously leaves the
freshly cut cane exposed for a period and also requires a second pass
through the garden trying to find all the fresh cuts.

Borers are just one of the nusances we have to put up with and find an
approach that works for each individual gardener.

Unfortunately there is no magic bullet.

Tim