of vineyard pests

1. Habitat manipulation is important for enhancing biological control of arthropod pests, but identification of selective food plants that benefit only natural enemies is required in order to avoid inadvertently exacerbating pest damage. 2. Greenhouse experiments were conducted to identify potential ground-cover plant species that would improve performance of the egg parasitoid Trichogramma carverae when mass released in vineyards to control the leafroller pest Epiphyas postvittana. Further experiments determined which plants increased immature survival and adult longevity of E. postvittana and a field experiment investigated field enhancement of biological control. 3. Greenhouse survival of T. carverae was greater in the presence of flowering shoots of Lobularia maritima than with flowering shoots of either Brassica juncea or Coriandrum sativum, or with shoots of any species from which flowers had been removed or a control with no shoots. Similar experiments with Fagopyrum esculentum and Borage officinalis showed survival was higher in the presence of shoots with flowers than in without-flower and control treatments. 4. Daily fecundity of T. carverae was greater in the presence of flowering shoots of L. maritim