Biological Control of Cereal Aphids in Wheat: Implications of Alternative Foods and Intraguild Predation
North Central Agricultural Research Laboratory
2011 Annual Report
1a.Objectives (from AD-416)
1. Objective 1. Determine the mechanisms whereby the availability of alternative prey and plant-provided resources affect pest suppression by carnivorous and omnivorous ladybeetles.
2. Objective 2. Characterize the IGP interactions between omnivorous and carnivorous ladybeetles within wheat systems and assess the impact of these interactions on cereal aphid predation.
3. Objective 3. Evaluate how spatial patterns in the availability of non-prey resources and IGP affect predation on cereal aphids by omnivorous and carnivorous ladybeetles.
1b.Approach (from AD-416)
Novel tools, including molecular and biochemical gut content analysis and geospatial analysis, will be coupled with traditional techniques used to monitor insect populations and predator efficacy. Our approach will, under field conditions, manipulate key alternative foods and IG contests to determine how these individual interactions contribute to the ability of ladybeetles to suppress cereal aphids within systems where cover crop and field margin management strategies are evaluated in production scale plots. Using these strategies, the proposed project will not only provide cost-effective and realistic solutions for pest management issues faced by Israeli and American producers, but also will provide a better understanding of how spatial dispersion, IG predation, and the availability of alternative foods contribute to biological control by omnivores and carnivores within agroecosystems.
Spring wheat was planted, and sugar sprays were applied weekly to field margins that had been planted to alfalfa. Insects in the soil and plant foliage were counted weekly along a grid, so that we could analyze the spatial distribution of beneficial and pest insects with relation to sugar availability. Predators were placed in the freezer, so that we can analyze their stomachs for consuming cereal aphids and sugar.