Differential response of the epigeal arthropod community to tillage and pesticide-treated seeds in a corn-soybean rotation

Soil tillage and pesticide seed treatments are both common in annual feed grain rotations in the US. Tillage is used to control weeds and prepare seedbeds for planting; however, because of the detrimental effects of tillage on soil health, there is much interest in reduced- and no-tillage practices. Pesticide seed treatments, seed coatings containing a mixture of systemic and contact fungicides and insecticides, are commonly applied to corn and soybean to protect the crop against soil-inhabiting insect pests and soil-borne fungal pathogens during the early stages of plant development. Our study examined how tillage systems and pesticide seed treatments may interact to influence soil arthropod communities in a corn-soybean rotation. We conducted a three-year field experiment in southeast New Hampshire, USA from 2017-2019. Corn and soybean were planted in rotation with and without pesticide seed treatments and under three tillage systems (full-, strip-, and no-till) in a randomized complete block design with four replications. Using pitfall traps, we sampled arthropod communities in each plot during the growing season from September to October 2018-2019 and the trapped arthropods were counted and identified to species level. Carabid beetle and other arthropod data were analyzed with analysis of variance and several multivariate techniques. Arthropod communities differed based on pesticide seed treatment in 2018 and tillage system in 2019 (PerMANOVA: P< 0.05). There were no interactions between pesticide seed treatment and tillage system in either year. Our data provide evidence that both pesticide seed treatments and tillage systems can influence arthropod communities in agroecosystems.