Selection of spatial placements of insectary plants to manage arthropod pests in vegetable production

Integrated pest management is a sustainable approach that utilizes multiple strategies to minimize arthropod pests in crops. Insectary plants, which are flowering plants that attract natural enemies used in crop fields to increase the population of natural enemies, are a conservation biological control strategy. However, information on the effectiveness of different spatial arrangements of insectary plants in vegetable production is still limited. Therefore, this study aims to find the efficacy of various spatial arrangements of insectary plants within a crop field using pest pressure and natural enemies as the study parameters. We conducted an experiment in Nashville, TN, in 2024 using buckwheat and sweet alyssum, as our previous research had shown that these two insectary plants could attract a diverse group of natural enemies compared to others. We used a randomized complete block design and arranged insectary plants with the main crop (green beans) in five spatial arrangements. We used green beans without insectary plants as the control. We took samples at three locations within a plot: first 1.5m, then 1.5-3m, and last, 8.5-10m using visual observations, beatsheet sampling, pitfall traps, flower collections, and yield assessments. Natural enemies, like minute pirate bugs, big-eyed bugs, and ground beetles, were observed visiting insectary plants and the adjacent crop plants. A significantly higher abundance of natural enemies was observed in flowering plants within the first 1.5m and the adjacent main crop in the 1.5-3m. Using optimum field spacings to integrate insectary plants within crop plants can help control arthropod pests in vegetable production.