- Author: Houston Wilson
Leafhopper egg deposition continues on both white and red varieties. Eggs of western grape leafhopper (WGLH) are now present at all of the monitoring sites.
Eggs of Virginia creeper leafhopper (VCLH) on white varieties are close to full maturity (eye spot is present) and we observed our first VCLH nymphs (1st instars) last week at the "Hopland" and "Ukiah/Talmage" sites (both are Chardonnay).
Nymph emergence will continue to increase in the coming weeks, so now is the time to start thinking about monitoring nymph populations in your vineyard. Leafhopper nymph identification guidelines are available here (video) and here (text version).
Due to the lack of biological control, effective early-season control of VCLH is critical. Based on monitoring, if control measures are needed, the optimum application period would be when the majority of the population is still in the younger nymphal stages before the emergence of adults. This is especially important if you plan to spray with an oil. Depending on population levels at your site, a follow-up application may be required to impact nymphs that emerge after the spray. Consult your PCA for materials, rates and timing.
On Friday May 12 we released 2 batches of Anagrus daanei in Lake County at vineyards in the Big Valley area.