How to Manage Pests
UC Pest Management Guidelines
Both leafhopper species overwinter in the egg stage. Rose leafhopper eggs are laid in young stems on plants of the rose family (including caneberries), and white apple leafhopper eggs are laid in 3- to 4-year-old apple twigs. Eggs of both species cause a pimplelike swelling of the bark where they are laid. Overwintered eggs begin to hatch in mid-April. The nymphs develop on their overwintering hosts and disperse as adults in early June. Adults of both species are present by June; both are white, about 1/8 inch (3 mm) long, and cannot be readily distinguished from each other. They rest on the undersides of leaves and fly actively on warm days. There are two generations of white apple leafhoppers and three generations of rose leafhoppers per year.
Like mites, leafhoppers damage blackberry and raspberry leaves by sucking on leaf tissue and removing green chloroplasts from cells, thus preventing the proper functioning of leaves. Heavily infested leaves are speckled with white markings. They also bear cast skins and tiny specks of black excrement. Leafhoppers do not feed on fruit but can contaminate it with black specks of excrement.
Parasitization of eggs may play a significant role in keeping populations of leafhoppers in check. Another factor is predators, which include green lacewings and minute pirate bugs. If high populations of leafhoppers develop, apply a treatment.
UC IPM Pest Management Guidelines: Caneberries