Evaluation of Insect Dynamics in Southeastern Cover Cropping Systems.

Current research suggests winter cover crops could be useful for improving insect pest control in southeastern row crop systems, but analyzing this elaborate relationship between plants and insects is complex. Since certain cover crops may be attractive to both beneficial and pest insects, decisions regarding cover crop species and management should be weighed carefully. Research is needed to determine the effect of winter cover crop species and mixtures on insect dynamics in southeastern row crop systems. Studies were established at the Tennessee Valley Research and Extension Center (TVREC) in Belle Mina, AL and the Wiregrass Research and Extension Center (WREC) in Headland, AL to evaluate the effect of crimson clover (Trifolium incarnatum), cereal rye (Secale cereale), and forage radish (Raphanus sativus) monocultures and mixtures on beneficial and pest insect abundance. Each cover crop treatment was replicated four times in both dryland and irrigated production systems at each location. All cover crops were fall-planted in a soybean-cotton rotation at TVREC and a peanut-cotton rotation at WREC and were chemically terminated 2-3 weeks prior to cash crop planting. Insect samples were collected: 1) in late April prior to cover crop termination and 2) bi-weekly during the cash crop growing season using sweep nets with a total of 10 sweeps per plot. Pest and beneficial insect populations were quantified according to treatment and separated at the species level to determine insect abundance. Regional differences in abundance of pests and beneficials in cover crops treatments were observed in this study, particularly in the rye monoculture. Clover containing treatments had greater populations of tarnished plant bugs compared to rye treatments at both locations during the cover crop growing season. Planting a mixture of cover crop species did not increase the number of beneficial insects compared to clover alone. Further results will be discussed.