Seasonal abundance of key alfalfa (Fabaceae) seed production pests and their natural enemies in southern Alberta, Canada

The economic importance of insect pests in agricultural fields and the potential biological control by their natural enemies warrant foundational studies for the development of integrated pest management strategies. An insect survey was conducted in alfalfa (Fabaceae) seed production fields in southern Alberta, Canada, during the bud, flowering, and seed crop stages in 2020 and 2021. We examined the seasonal abundance of Hypera postica (Gyllenhal) (Coleoptera: Curculionidae), Adelphocoris lineolatus (Goeze) (Hemiptera: Miridae), Lygus spp. Hahn (Hemiptera: Miridae), and 12 natural enemy taxa. We also examined the seasonal abundance, richness, and diversity of generalist predators and the seasonality of the two H. postica parasitoids, Bathyplectes curculionis (Thomson) (Hymenoptera: Ichneumonidae) and Oomyzus incertus (Ratzeburg) (Hymenoptera: Eulophidae). The seasonality of pests and natural enemies was inconsistent between years. Hypera postica larvae, B. curculionis, and O. incertus were present from mid-June to mid-August. However, we detected no correlations between H. postica larvae and its two parasitoids in either year. A number of generalist predators were correlated with A. lineolatus and Lygus spp. Further research is needed to understand the effects of environmental and biotic factors on the seasonality of pests and natural enemies in alfalfa seed production fields, and the insects’ trophic interactions.