Corn (Zea mays L.) gluten meal (CGM) was evaluated under greenhouse conditions for efficacy on 22 selected monocotyledonous and dicotyledonous weed species. Corn gluten meal was applied at 0, 324, 649, and 973 g·m–2 and as a soil-surface preemergence (PRE) and preplant-incorporated (PPI) weed control product. CGM reduced plant survival, shoot length, and root development of all tested species. Black nightshade (Solanum nigrum L.), common lambsquarters (Chenopodium album L.), creeping bentgrass (Agrostis palustris Huds.), curly dock (Rumex crispus L.), purslane (Portulaca oleracea L.), and redroot pigweed (Amaranthus retroflexus L.) were the most susceptible species. Plant survival and root development for these species were reduced by ≥75%, and shoot length was decreased by >50% when treated PRE and PPI with 324 g CGM/m2. Catchweed bedstraw (Galium aparine L.), dandelion (Taraxacum officinale Weber), giant foxtail (Setaria faberi Herrm.), and smooth crabgrass [Digitaria ischaemum (Schreb.) Schreb. ex Muhl] exhibited survival and shoot length reductions >50% and an 80% reduction in root development when treated with PPI CGM at 324 g·m–2. Barnyardgrass [Echinochloa crus-galli (L.) Beauv.] and velvetleaf (Abutilon theophrasti Medic.) were the least susceptible species showing survival reductions ≤31% when treated with 324 g CGM/m2.

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Annual grassy weeds often inhibit establishment of spring-seeded creeping bentgrass (Agrostis palustris Huds.) on golf courses. The objective of this experiment was to evaluate the safety of the annual grass herbicide quinclorac in spring-seeded creeping bentgrass in varying climatic regions of the United States. Experiments were initiated in Indiana, Iowa, and North Carolina in Spring 2000. Treatments included siduron at 6.72 kg·ha-1 a.i. applied immediately prior to planting (PRE), and quinclorac at 0.84 kg·ha-1 a.i. applied 7 days before seeding (DBS), PRE, and 14 or 28 days after emergence (DAE). Herbicides were applied to three creeping bentgrass cultivars at each location. Siduron reduced establishment of `Providence', `L93', and `Putter' creeping bentgrass in Indiana. Quinclorac applied PRE, 14 DAE, and 28 DAE caused short-term phytotoxicity, primarily in `Providence' in Indiana. Quinclorac applications did not significantly affect cover of `Providence', `L93', or `Putter' in Indiana or `L93', `Pennlinks', or `Penncross' in Iowa. All applications of quinclorac reduced cover of `L93', `Pennlinks', and `Penncross' in North Carolina. Though quinclorac applications resulted in no long-term damage when applied to creeping bentgrass seedlings in Indiana or Iowa, results from North Carolina indicate that caution should be exercised when using quinclorac on seedlings of creeping bentgrass. Chemical names used: 3,7-dichloro-8-quinolinecarboxylic acid (quinclorac); 1-(2-methylcyclohexyl)-3-phenylurea (siduron).

Concerns over ground water contamination and other environmental issues have prompted research to reduce synthetic herbicide use. Corn (Zea mays L.) gluten meal, a 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 ai 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 gluten meal. As the application rate 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 decreased from 88 to 29 mg ai m−2. There was no increase in crabgrass control in plots that received amounts of corn gluten meal and pendimethalin exceeding these combined rates.