Sustainable Controls for Vine Mealybug

As part of an ongoing foreign exploration and importation initiative for vine mealybug, Planococcus ficus, parasitoids collected in the Mediterranean (Spain, northern Italy, and Sicily) and South Africa were screened for their potential to lower mealybug populations in California. Studies in 2009 focused on geographic strains of Anagyrus pseudococci. Molecular studies showed clear separation of geographic populations in northern Italy, eastern Spain, Israel and California more similar than material collected in Argentina, Sicily. Studies conducted in large field cages suggest that A. pseudococci material from Spain may be better suited to control vine mealybug populations in California, although these results are preliminary. Contacts have been made with entomologists in Iran, Spain and Argentina for the importation of novel vine mealybug parasitoids in 2010. Contacts have also been made with entomologists in Chile and New Zealand for the importation of novel obscure mealybug parasitoids in 2010. In 2009, releases of A. pseudococci and Coccidoxenoides perminutus were made in vineyards in the in San Joaquin Valley (SJV), the Northern Interior Winegrape Region (Sacramento and San Joaquin Counties), and the Central Coast (San Luis Obispo County) regions. There were approximately 10,000 A. pseudococci Sicily, 2,000 A. pseudococci Spain, and 10,000 C. perminutus released in both open-air and caged vine trials. To date, we have recovered A. pseudococci at all sites. We have recovered C. perminutus from all regions, but not from all sites. The releases were made in combination with sustainable control tools (mating disruption and, when needed, Argentine ant controls) and a planned reduction in pesticide use, particularly organophosphates. In each region, a paired-plot design was used with sustainable and conventional treatments paired in each vineyard block, and 5-6 vineyards as replicates in each region. There were few differences between treatments as, in most cases, insecticide use did not vary between sustainable and conventional treatments. Trials investigating the rate of dispensers used in mating disruption programs showed lower trap catches when dispensers were released at 188 and 250 per acre than at 50 and 125 per acre (250 per acre is label rate). This trial will continue for two years to assess application rate for amting disruption, and the impact on parasitism levels.