Nothing but net: Hail netting as an effective tool for pest exclusion and fruit protection in a commercial Minnesota orchard

Exclusion netting in European and North American orchards is an effective control method for insect pests. These orchards have reduced costs and risks to the environment and non-target species with decreased dependence on traditional insecticides. This study examined commercially available hail netting (DrapeNet®; Prosser, WA) as a pest exclusion strategy in Minnesota. We also investigated subsequent effects of hail netting on fruit quality and yield, and on the diversity and abundance of natural enemies. We assessed the influence of hail netting by monitoring insect pest species, natural enemies, and fruit quality in netted and open plots in production systems with two levels of insecticide use in 2021 and 2022. Codling moth (Cydia pomonella L.) and the apple maggot (Rhagoletis pomonella Walsh) populations were significantly reduced inside the netting compared to open plots by 94% and 96%, respectively (p< 0.001). Insecticide application alone did not significantly reduce pest pressure in either species. Hail netting and insecticide application resulted in significantly higher proportions of high quality fruit at harvest; and the presence of netting did not significantly influence yield. For natural enemies, netting significantly reduced the number of generalist predators caught, but the diversity of natural enemies was significantly higher under netting. These findings suggest that hail netting: can effectively control key Midwest apple insect pests, does not pose a risk to high quality fruit production, and reduces the population of generalist predators but may not influence the biodiversity of predators present under netting.