Leafhopper Newsletter

Adults mostly passed peak but remain elevated, nymphs increasing - Sept. 14

MENDOCINO COUNTY

At most sites, densities of VCLH adults remain elevated while WGLH adult populations have peaked and are now in decline, with the exception of Potter and Redwood Valley, where WGLH adult densities may be rising again. Nymph densities of both VCLH and WGLH appear to have passed peak, although at some sites densities continue to increase.

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). 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).

PARASITOID RELEASE PROGRAM

No parasitoids were released last week in order to build up populations in our greenhouse colonies in preparation for the fall-winter period. The next release is scheduled for September 23 in Mendocino County, but this si contingent on parasitoid densities in the colony.