Management of aphids on winter high tunnel crops

Abstract

High tunnels offer several benefits to specialty crop growers including crop protection and season extension. Although crops are actively grown in high tunnels during the winter, few management recommendations exist for winter pests that are actively feeding and reproducing in this protected environment. This study evaluated the efficacy of three commercially available predators used for the augmentative biological control of aphids, Adalia bipunctata, Orius insidiosus, and Chrysoperla carnea, in combination with OMRI-approved pesticides labeled for aphids on spinach and strawberry. Pesticides included PyGanic (pyrethrin), Neemix (azadirachtin), and Sil-MATRIX (Potassium silicate). Laboratory and field experiments indicate high survival of biocontrol agents under row covers in high tunnels, and preventative and/or curative management of aphids. Spray trials had varied results, but spinach marketability was highest in plots that received PyGanic while strawberry marketability was lowest in this treatment. We also observed high compatibility of predators with each spray product, with one exception being A. bipunctata that was susceptible to PyGanic in one experiment. Strawberry yield (weight per plant) and spinach marketability was negatively correlated with accumulated aphid days in our study, indicating a need for aphid management in these crops during winter.