Spray with an insecticide or insecticidal soap. In the fall, rake up leaves and remove weeds that can harbor leafhopper eggs through the winter. Growing tips, foliage and canes wilt. Swollen areas up to 1 inch long appear on canes. Borers, moth larvae that are white or yellow worms up to 1 inch long.
Borers enter the canes through wounds and through pruned stem tips.
Cut off the affected area. Make the cut below the swelling on the cane to be sure you remove the borer. To prevent borers from entering canes, apply shellac or white glue to the exposed tips after pruning. Overnight roses are chewed and trampled. Buds and blooms are damaged the most.