Chapter 35 The Use of Corn Gluten Meal As A Natural Preemergence Weed Control in Turf

In a study involving the use of food-grade corn meal as a growth media for microorganisms, it was observed that stand establishment of creeping bentgrass seedlings was reduced by the incorporation of corn meal into the soil. Studies on the effect of adding corn starch, corn gluten meal, corn germ, corn seed fiber, or corn meal to the soil surface before seeding creeping bentgrass (Agrostis palustris Huds.) demonstrated that the greatest concentration of the inhibitory substance responsible for stand reduction was in the corn gluten meal. Further studies have shown that corn gluten meal contains a substance that inhibits root formation in several species, including crabgrass (Digitaria spp.). Gluten meal is the protein fraction of the corn extracted in the wet-milling process and is used as an animal feed. It contains approximately 10% nitrogen (N) by weight and makes a good natural fertilizer for turf. In field studies on the effect of corn gluten meal on crabgrass control, larger amounts were required when the material was applied 4 weeks before crabgrass germination than when it was applied 1 week before germination. Corn gluten meal applied at 99, 198, 297, 396, 495, and 594 g m reduced crabgrass infestation by 50, 65, 80, 95, and 93%, respectively when applied 1 week before application. INTRODUCTION The last few years have brought increased public interest in environmental issues concerning the use of pesticides. This has been particularly true in the turf industry in which the general public may be involved in the applications of pesticides to their own lawns or may see the application of these materials on golf courses or by lawn care companies. With this concern has come an increased interest in natural products that are perceived by the public as being safer than traditional synthetic pesticides. In 1986, a research project involving food-grade corn meal as a growth medium for a microorganism produced some observations that led to the patenting of a natural organic product for the preemergence control of annual weeds. The objective of this work was to establish a Pythium fungi in the soil of a new golf course green that had been constructed at the Iowa State University turfgrass research area. The effects of this pathogen were then to be observed on creeping bentgrass (Agrostis palustris Huds.) ____________________ Published as Journal Paper no. J-14957 of the Iowa Agric. and Home Econ. Exp. Stn., Ames. Project No. 2231.