Biological Control of Cereal Aphids in Wheat: Implications of Alternative Foods and Intraguild Predation
North Central Agricultural Research Laboratory
2013 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 IS and US 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.
Field work was completed in 2012 for this project. The past year has been spent processing samples collected from the 2010-2011 growing seasons. To date, all insect samples (>5,000 specimens) have now been identified to as low a taxonomic level as possible, and have been entered into a series of databases. Using the cold anthrone test, we analyzed the stomachs of 1,207 insect predators for the presence of sugar feeding. Finally, we analyzed the stomach contents of 73 predators collected near aphid-infested areas for the presence of aphid DNA. Manuscripts on this research are now in preparation for submission over the next 12 month cycle.