Putting the research spotlight on weed biology can aid development of better integrated pest management practices for snapbeans, a crop widely grown in the Midwest. Crops can tolerate varying degrees of weed competition with- out adverse effects on crop growth and yield. These weeds are prolific seed producers, emerging from May to September during the main cropping season for snapbeans. At densities greater than two plants per row foot, redroot pigweed and large crabgrass emerging with the snapbeans reduce yield. Later-emerging weeds do not significantly affect yield.
Weeds also can affect insect pests.
Populations of two insect pests, potato leafhopper and bean leaf beetle, are being monitored as well to determine if changes in weed density affect the potential influence of these pests on snapbean production. Snapbeans growing in rye mulch Snapbean plot with pigweed Reduced tillage high residue systems can prevent soil erosion, improve soil tilth, and suppress weeds in vegetable crops. By changing the crop environment, these alternative production systems also can affect other pests and may lower crop yields. The use of strip tillage was found to reduce much of the adverse effects of cover crop mulches on vegetable crop yields, but additional modifications are needed to reduce risk and increase snapbean yields in reduced-tillage rye mulch systems.