Leafhopper Newsletter

Nymph emergence continues, starting to see adults - June 7

We are seeing 1st - 5th instar (stage) nymphs, although most are 3rd - 4th instar. Some freshly molted adults were also observed, indicating the beginning of adult emergence. Approximately 92% of the Virginia creeper and 77% of the Western grape leafhopper eggs have emerged.

We project that this week (June 5-11) we will continue to see more 4th and 5th instar nymphs as well as increased adult emergence. Adult populations should continue to grow in the following week (June 12-18) and most of the remaining nymphs will likely be close to molting.

If you have not done so yet, this is the week to monitor your vineyard to determine is control measures will be necessary.

Parasitism of Western grape leafhopper has been consistent at all sites since May 5, indicating that the regional population of Anagrus spp. parasitoids have colonized the vineyards. There is practically no parasitism of Virginia creeper leafhopper.

A batch of Anagrus daanei, the parasitoid that controls Virginia creeper leafhopper, was released on June 3 in Mendocino County near McDowell Valley.