Assessing the efficacy of hail-netting for sustainable apple pest management in Minnesota

Apple growers in Minnesota contend with several specific and generalist insect pests that, if managed poorly, can lead to major crop losses. The primary pests, during the majority of the season, include Codling moth (Cydia pomonella),apple maggot (Rhagoletis pomonella), and red-banded leafroller (Argyrotaenia velutinana). Growers continue to seek integrated pest management (IPM) tactics that are more sustainable and economical than traditional pesticide use, while also avoiding increased risk to yields. Physical exclusion of insect pests is a possible tactic that is gaining interest; however, it must be proven effective and economical. In 2020, researchers in Minnesota found that netting, used to protect high-value apples from hail, could be effective for exclusion of selected pest species. Preliminary results indicated the netting (Drape-Net, N. America) decreased codling moth numbers by 92% and red-banded leafroller by 78%. Our study was expanded to include apple maggot and fruit damage assessment. We assessed the efficacy of hail-netting by trapping pest species and measuring apple damage in both IPM and transitional organic production systems at two commercial orchards over the course of 3 months. Our findings show that all three pest species were significantly reduced inside the netting (P<0.05). These findings suggest that in addition to the economic benefits of hail protection, the netting used in this study may prove very effective at physical exclusion of several key apple pests, which in turn may also reduce insecticide use in Minnesota orchards.