Impact of Post-Harvest Management Practices in Corn (Zea mays L.) Fields on Arthropods in Subsequent Soybean (Glycine max [L.] Merr.) Plantings

SIMPLE SUMMARY: Soybean plantings typically consist of a diversity of herbivores and beneficial arthropods. In many instances, soybean producers rely on insecticide sprays to suppress pestiferous insects. However, these sprays may prove more damaging than beneficial. Increased vegetation diversity aims to enhance natural enemy abundance and efficacy and subsequently reduce pest populations more sustainably. The aim of this study was to investigate the impact of three post-harvest practices in corn, resulting in varying levels of plant residue remaining on the soil surface, on populations of arthropod pests and beneficials within a subsequent soybean crop. Overall, insect herbivore abundance was greater in soybean with no cover crop and/or corn plant residue. However, the abundance of predators within the soybean foliage was similar among plots with plant residue or most residue removed via plowing. Among ground predators, spider activity density was greatest in soybean where residue was plowed under. Stink bug egg mortality due to predation and parasitism were inconsistent among treatments. Findings suggest that post-harvest practices investigated during this study will have a similar influence on most ground and foliar arthropods. However, post-harvest practices that limit tillage and maintain plant residue on the surface promote long-term sustainable ecosystems that benefit society. ABSTRACT: There is increased adoption of cover cropping and conservation tillage in the USA. Many farmers view these practices as methods for improving their soils. However, different cover cropping and tillage practices conducted post-harvest can have a disparate impact on arthropods within the subsequent cash crop. Field experiments were conducted during 2017 and 2018 at two experimental sites to examine the influences of different post-harvest practices following corn (Zea mays L.) harvest on pests and beneficials in subsequent soybean [Glycine max (L.) Merr.] plantings. Experimental treatments included: (1) tillage via chisel plow (CP), (2) no-tillage in which corn residue/stubble remained on the soil surface (CS), and (3) planting a cover crop into corn residue (CC) following corn harvest. Overall, insect herbivore abundance was greater in the CP treatment. Foliar predator numbers were similar among treatments or of greater abundance in CP. The activity density of epigeal insect predators varied according to site and feeding guild. However, spider activity density was greatest in CP. Stink bug egg mortality due to predation and parasitism varied among treatments. However, the percentage of stink bug eggs that hatched was greatest in the CC during both years. Findings suggest that post-harvest practices investigated during this study will have a similar influence on most epigeal and foliar arthropods in soybean.