It is difficult to say what kind of larvae are boring into your rose roots. To get rid of them: Prune the rose canes to be 5 to 6 inches high, then gently dig up the shrub, hose off the roots (over a barrel or bucket full of warm soapy water) until all of the larvae are gone from the roots, remove the affected soil and replace it with new soil and compost, and replant. If the rose is too badly damaged, consider replanting with a new rose. Be sure the larvae are dead before discarding them. If done in the fall, your rose should bounce right back in the spring.
It is difficult to say what kind of larvae are boring into your rose roots. To get rid of them: Prune the rose canes to be 5 to 6 inches high, then gently dig up the shrub, hose off the roots (over a barrel or bucket full of warm soapy water) until all of the larvae are gone from the roots, remove the affected soil and replace it with new soil and compost, and replant. If the rose is too badly damaged, consider replanting with a new rose. Be sure the larvae are dead before discarding them. If done in the fall, your rose should bounce right back in the spring.