PENDIMETHALIN AND CORN GLUTEN MEAL COMBINATIONS TO CONTROL TURF WEEDS

Concerns over ground water contamination and other environmental issue s have prompted research to reduce? synthetic herbicide use, Corn (Zea mays L.) gluten meal, a by-product of wet milling, inhibits germinati on and the establishment of many annual and perennial weed species, Ou r objective in the field was to investigate crabgrass control (Digitar ia spp.) in Kentucky Bluegrass (Poa pratensis L.) turf established on a Nicollet soil (fine-loamy, mixed, mesic Aquic Hapludoll), In the gre enhouse, we investigated the control of large crabgrass [Digitaria san guinalis (L.) Scop,] on the same soil with no turfgrass cover. Experim ents were conducted with corn gluten meal at 0, 49, 98, and 147 g m(-2 ) combined in a factorial arrangement with pendimethalin -ethylpropyl) -3,4-dimethyl-2,6-dinitrobenzenamine] at 0, 29, 59, 88, and 117 mg ai m(-2). The minimum label rate for pendimethalin is 176 mg ai m(-2). Fi eld crabgrass control was improved by application of a sublethal rate of pendimethalin in addition to corn gluten meal. As the application r ate of corn gluten meal increased from 49 to 147 g m(-2), the level of pendimethalin required to provide 75 to 85% control for 15 wk decreas ed from 88 to 29 mg ai m(-2). There was no increase in crabgrass contr ol in plots that received amounts of corn gluten meal and pendimethali n exceeding these combined rates.