Biological Control Services from Parasitic Hymenoptera in Urban Agriculture

Urban Farm DB summary

Over two growing seasons, this study sampled brassica crops at urban agriculture sites spanning a gradient of surrounding landscape imperviousness, size, and management to assess parasitic Hymenoptera abundance, richness, and parasitism of the cabbage aphid. On-farm agroecological practices—mulch coverage, floral richness, and crop-plant richness—and larger on-farm noncrop area increased parasitoid abundance, and greater crop-plant richness raised aphid parasitism, supporting the enemies hypothesis in urban agroecosystems.