Natural enemies (predacious and parasitic arthropods) are valuable partners for crop growers in managing the pest insects in agroecosystems. Typically, we value natural enemies based on their ability to consume insect herbivores and therefore remove the pest from the crop. However, the mere risk of predation can provoke changes in herbivore behavior and physiology that can influence herbivore reproductive capacity and survival. It has been shown that predation risk can reduce insect herbivore populations almost as significantly as predation itself. Despite this promise, little work has been done to harness risk effects as a potential pest management strategy, in addition to identifying the mechanisms insect herbivores use to identify predation risk. The goal of our research is to 1) identify what mechanisms insect herbivores use to determine predation risk and 2) successfully mimic those cues. We ask these questions using the herbivorous green peach aphid (Myzus persicae (Sulzer)), the predatory multi-colored Asian lady beetle (Harmonia axyridis), and collards (Brassica oleracea) as a system. Our research has demonstrated that H. axyridis odor cues reduce M. persicae reproductive capacity, deter host-plant colonization, and stifle aphid population size. The second component of this study was to create a synthetic blend of compounds that mimic the odor profile of Harmonia axyridis by identifying the compounds using GC-MS, and assessing their bioactivity of the compounds using GC-EAG. With this information, we are able to determine which compounds M. persicae uses to identify Harmonia axyridis, and assess the efficacy of this synthetic blend in comparison to cues given off by live lady beetles. Ultimately, this tool will be used to evaluate aphid colonization and population size in several vegetable crops during the summer growing season. This work highlights a promising area of research that merges chemical ecology with sustainable pest management, with possible uses in numerous agricultural commodities.

Nosy pests: Exploiting predatory insect odors to control aphid pests in sustainable crop production

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ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.