D3077: Cover-cash crop rotations affect arthropod community dynamics: Lessons from a multi-year participatory research in the Lower Rio Grande Valley

Recent studies have demonstrated that introducing conservation practices such as cover cropping into the agroecosystem can promote diverse communities of beneficial arthropods such as predators, parasitoids, and even pollinators for the subsequent cash crops. However, the effects of cover crops on arthropod community dynamics and their potential in managing pest populations in agroecosystems is not well understood. To address this, a four-year field experiment in collaboration with local growers in four fields (~750 acres) in the Lower Rio Grande Valley was designed to evaluate the impact of cover crops planted in the summer months on the subsequent cash crops in the winter. We hypothesized that cover crops would attract and provide refuge for beneficial arthropods, leading to the repulsion or reduction of the pest population in the subsequent cash crop. The arthropod community were assessed using a comprehensive trapping method comprising pitfall, sticky, and vane traps replicated multiple times over each crop season. Our preliminary results from year 1 show that cover crops support more pollinators in the early summer season, and similar effects are also observed in subsequent cash crops. The population of herbivores and natural enemies remains unaltered by cover crops in the summer and cash crop growing season. There was also a significant difference in the population of arthropods based on their taxonomic order and feeding guilds. Our results indicate that cover crops mediate plant arthropod interactions which can have cascading effects on the population of herbivores and beneficials in the agroecosystem and should be further explored.