Description of the Pest
Most leafhoppers are minor problems on potatoes in California with the exception of the beet leafhopper. Adults are small, pale green or mottled brown, somewhat wedge shaped, and about 0.12 inch (3 mm) long. Nymphs are whitish to pale green and move rapidly when disturbed. Both adults and nymphs are found on the underside of the leaves.
Leafhoppers feed by sucking sap from the plant causing a white to yellowish stippling of the leaves, browning of the leaves, or yellowing of lower leaves depending upon the species involved. The beet leafhopper is responsible for transmitting the curly top virus.
Treatment is occasionally necessary in California; however, treatment thresholds have not been established. Keep weeds controlled in and around the field, especially with late spring plantings in the southern San Joaquin Valley. The insecticides suggested for control of aphids and flea beetles will control leafhopper populations.