Conservation biological control of agricultural pests can be elusive in intensively farmed, annual crop systems. In such highly disturbed systems, extra-farm vegetation may be critical habitat for maintaining local natural enemy populations and conserving the biological control services they provide. We investigated the importance of natural vegetation in maintaining ichneumonid wasp diversity, an indicator taxon for biodiversity and biological control services, at 35 commercial farm sites in the Central Coast region of California. Wasps were sampled using Malaise traps in May, July, and September in 2004, 2005, and 2006. Landuse and vegetation classes were characterized by manual aerial photo interpretation with GPS field-verification at two landscape scales (0.5km and 1.5km radii from farm centers) and quantified as percentages of landscape area. Research landscapes ranged from primarily agricultural to complex vegetation-landuse mosaics. Initial analyses using 10 research sites, with combined vegetation classes and insect samples across years, showed a positive correlation between ichneumonid diversity and percent of landscape under unmanaged vegetation at both landscape scales. Separate analyses on single and combined vegetation classes across all 35 sites will be reported to determine if specific types of natural vegetation are strongly associated with ichneumonid diversity. Taxa of interest to natural biological control will be highlighted. Opportunities and constraints for enhancing biodiversity and biological control in agricultural landscapes will be addressed.