Influence of alternative cover cropping on ground dwelling predators in a cotton agroecosystem

Integration of living or dead mulches coupled with reduced tillage in agricultural production systems may allow growers to utilize fewer pesticide applications to manage insects and weeds, thereby improving economic returns while increasing ecosystem services. Basic research is needed to demonstrate simple, cost effective solutions that promote insect natural enemies.  The objective of this study was to evaluate the suitability of different living and dead mulches to increase natural enemy abundance and species richness in a cotton agroecosystem. Replicated cotton plots, measuring 7.3 by 12.2 m, were established using conventional tillage (control) or strip tillage into winter cover crops including crimson clover, white clover, or rye; crimson clover and rye were terminated prior to cotton planting while the white clover continued to grow as a green mulch throughout the summer.  Pitfall samples were taken monthly over the growing season to assess arthropod communities. For the first two sampling dates (April and May), we collected a total of 13,250 arthropods; relative abundance of ground dwelling predators was dominated by five groups: fire ants, ground beetles, rove beetles, spiders and earwigs, respectively. Capture of these arthropods varied by date and in white clover and crimson clover treatments activity of some predators was greater compared to the remaining treatments. These results provide further evidence in seasonality of ground-dwelling predatory communities and preliminary evidence that mulches can increase natural enemy abundance and species richness within these communities.