Spray with Bacillus thuringiensis , called Bt, a bacterium fatal to caterpillars but harmless to plants and other animals. If caterpillars return to your garden every spring, Bt can be sprayed in anticipation of the problem. Upper surfaces of leaves are covered with small yellow specks. Leaves may curl. They feed on the undersides of leaves and suck the sap from the foliage.
Leafhoppers can carry and spread diseases.
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.