Leafhopper Newsletter

Adults mostly passed peak but remain elevated, nymphs increasing - Sept. 7

MENDOCINO COUNTY

Densities of VCLH adults remain elevated at most sites while peak WGLH adult populations are starting to decline. Nymph densities of both VCLH and WGLH continue to increase or remain high, with the exception of Potter and Redwood Valley, where WGLH populations have been declining. For the WGLH, the current nymph population represents the second brood whereas for VCLH the nymphs are likely third brood.

LAKE COUNTY

VCLH densities are generally low and more variable across all sites (less than 3 adults per trap). No VCLH nymphs have been observed since mid-July, with the recent exception of Scotts Valley, but densities are still very low (less than 0.5 nymphs per leaf). These VCLH nymphs represent the third brood.

WGLH adult populations have peaked at all sites and we are now seeing nymph densities peaking (or just passed peak) at most sites with the exception of "Finley" (no WGLH nymphs observed since June). These nymphs represent the second WGLH brood.

PARASITOID RELEASE PROGRAM

A batche of Anagrus daanei, the parasitoid that controls VCLH, was released on September 2 at a vineyard in Mendocino County in the Hopland area. The next release is scheduled for September 16 in Mendocino County.