From March 15 and throughout the 1997 growing season, intensive weekly sampling of herbivorous insects (mainly leafhoppers and thrips) and associated natural enemies (mainly Anagrus sp and Orius sp) have been conducted in two adjacent Chardonnay vineyard blocks of 5 acres each, North of Hopland. Both blocks are managed organically with half of the area of each block planted to summer cover crops (buckwheat and sunflower), and the other half maintained with bare ground.