A method for continuous rearing of grapevine leafhoppers, Erythroneura spp. (Hemiptera: Cicadellidae)

We report a two-step method to rear three leafhopper species, Erythroneura elegantula Osborn, Erythroneura vitis (Harris), and Erythroneura ziczac Walsh, for experimental purposes on grapevines. The first step involves rearing adults on grapevines for reproduction, oviposition, and egg development. The second step involves rearing nymphs on isolated leaves placed in Petri dishes lined with agar. No mortality was observed and adults emerged in about three weeks. The three Erythroneura species were reared for 10 consecutive generations with minimal resources.

DEFINING ACTION LEVELS FOR LEAFHOPPERS ON THOMPSON SEEDLESS RAISIN VINEYARDS IN THE SAN JOAQUIN VALLEY OF CALIFORNIA

In the San Joaquin Valley of California, leafhoppers (Erythroneura elegantula and Erythroneura variabilis) can severely damage the foliage of grapevines resulting in economic loss. Most Thompson Seedless raisin vineyards, however, don't require treatment for leafhoppers every year. To help make the correct treatment decision, monitoring guidelines and action levels are important. This study provides information on monitoring techniques and action levels for this leafhopper complex. A sustained population of 20 nymphs per leaf during summer broods results in 20% to 30% visible damage to the canopy by harvest in early September. Populations higher than this may require chemical intervention to prevent an economic loss. The photosynthetic activity was reduced in proportion to visible leaf damage. Methods of estimating damage to the canopy from leafhopper activity are presented.