Native perennial conservation strips to enhance natural biological contol in Michigan blueberries

Conservation plantings of native wildflowers were established alongside highbush blueberry fields to test the hypothesis that provision of resources for natural enemies increases their abundance in adjacent crop fields without increasing the abundance of pest insects. For two growing seasons fields with flowering borders were compared to control fields where growers maintained mown grass perimeters. Insects were categorized according to their trophic level and impact on agriculture and their abundances were compared between years and treatments. Syrphid flies were significantly more abundant in fields with conservation strips, as were 3 out of 9 herbivorous groups of insects. Four out of 9 herbivorous insect groups decreased significantly in abundance from 2007 to 2008. The implications of these findings for pest management and conservation of biodiversity in farmland will be discussed.