Pendimethalin and corn gluten meal combinations to control turf weeds

Abstract

Concerns over ground water contamination and other environmental issues have prompted research to reduce synthetic herbicide use. Corn (Zea mays L.) gluten meal, by-product of wet milling, inhibits germination and the establishment of many annual and perennial weed species. Our objective in the field was to investigate crabgrass control (Digitaria spp.) in Kentucky Bluegrass (Poa pratensis L.) turf established on a Nicollet soil (fine-loamy, mixed, mesic Aquic Hapludoll). In the greenhouse, we investigated the control of large crabgrass [Digitaria sanguinalis (L.) Scop.] on the same soil with no turfgrass cover. Experiments were conducted with corn gluten meal at 0, 49, 98, and 147 g m-2 combined in a factorial arrangement with pendimethalin [N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine] at 0, 29, 59, 88, and 117 mg al m-2. The minimum label rate for pendimethalin is 176 mg ai m-2. Field crabgrass control was improved by application of a sublethal rate of pendimethalin in addition to corn glutea meal. As the application rate of corn gluten meal increased from 49 to 147 g m-1, the level of pendimethalin required to provide 75 to 85% control for 15 wk decreased from 88 to 29 mg al m-2. There was no increase in crabgrass control in plots that received amounts of corn glutea meal and pendimethalin exceeding these combined rates.