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.
|Common name||Amount per acre||R.E.I.‡||P.H.I.‡|
|(Example trade name)||(hours)||(days)|
|The following are ranked with the pesticides having the greatest IPM value listed first—the most effective and least harmful to natural enemies, honey bees, and the environment are at the top of the table. When choosing a pesticide, consider information relating to air and water quality, resistance management, and the pesticide's properties and application timing. Not all registered pesticides are listed. Always read the label of the product being used.|
|(Malathion 8)||1–2 pt||12||1|
|MODE-OF-ACTION GROUP NUMBER1: 1B|
|COMMENTS: Highly toxic to honey bees; do not apply if crop or weeds are in bloom.|
|(M-Pede)||1–2% volume by volume||12||0|
|MODE OF ACTION: A contact insecticide with smothering and barrier effects.|
|COMMENTS: Target first generation nymphs. Provides only a temporary reduction in the population levels, which generally rebound as a result of immigration.|
|‡||Restricted entry interval (R.E.I.) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (P.H.I.) is the number of days from treatment to harvest. In some cases the REI exceeds the PHI. The longer of two intervals is the minimum time that must elapse before harvest.|
|#||Acceptable for use on organically grown produce.|
|1||Rotate chemicals with a different mode-of-action Group number, and do not use products with the same mode-of-action Group number more than twice per season to help prevent development of resistance. For example, the organophosphates have a Group number of 1B; chemicals with a 1B Group number should be alternated with chemicals that have a Group number other than 1B. Mode of action Group numbers are assigned by IRAC (Insecticide Resistance Action Committee). For additional information, see their Web site at http://www.irac-online.org/.|
UC IPM Pest Management Guidelines: Caneberries
UC ANR Publication 3437
M. P. Bolda, UC Cooperative Extension, Santa Cruz County
L. J. Bettiga, UC Cooperative Extension, Monterey County