UC Davis entomologists are joining forces with plant breeders to develop solutions to the infestation of a pinhead-sized louse called phylloxera that is damaging grape vineyards throughout California. The tiny insect lives in the soil and attacks the roots of grapevines, sucking out the sap from the plant. One variety of phylloxera, known as Type A, has been present in California for 100 years. Growers dealt with it by planting vines on rootstocks that were resistant to that strain. However, in 1983, Jeffrey Granett, professor of entomology at UC Davis, discovered the presence of a new strain of phylloxera called Type B, which appears to have outwitted the resistant rootstocks and has attacked plants in Sonoma and Napa Counties. Granett and colleagues have surveyed the state for types A and B and are looking for new strains of the pest that have not yet been detected. "We're also testing various chemicals on phylloxera in the laboratory and looking more deeply into the physiological and ecological mechanisms of resistance," Granett says. Working with plant breeders in the UC Davis viticulture and enology department, he hopes to develop new, resistant rootstocks. "We anticipate that within 15 to 20 years, new rootstocks will be needed throughout California's wine-growing regions," he says. Granett will give a morning poster presentation on Tuesday, Dec. 10, explaining "Recent Research on Control of Grape Phylloxera."