Natural ecosystems are often sources of pest arthropods and their natural enemies for nearby agroecosystems. This study treats the ecology of the native California blackberry, Rubus ursinus Cham. and Schlecht, and an imported blackberry, Rubus procerus P.J. Mueller, the blackberry leaf-hopper (BLH), Dikrella califomica (Lawson), and its egg parasite, Anagrus epos Girault, in two riparian habitats and a vineyard site. Anagrus is also an effective natural enemy of the grape leafhopper (GLH), Erythroneura elegantula Osborn, which evolved on wild grape in the riparian habitat and became a serious pest after the introduction of commercial varieties.
