Submitted to: National Allium Research Conference
Publication Type: Abstract Only
Publication Acceptance Date: December 18, 2006
Publication Date: December 29, 2006
Citation: Webber III, C.L., Sherefler, J.W., Taylor, M.J. 2006. Corn gluten meal as a preemergence herbicide for spring-transplanted onions (Allium cepa L.) [abstract]. National Allium Research Conference. p. 42.
Onions (Allium cepa L.) are a potential alternative crop for Oklahoma and northeast Texas. Corn gluten meal is a certified organic material used for preemergence or preplant incorporated weed control. In 2002 and 2003 field research was conducted in southeast Oklahoma (Lane, OK) to determine the crop safety, weed control efficacy, and yield response to corn gluten meal (CGM) and selected preemergent synthetic herbicides (pendimethalin and oxyfluorfen) when used in spring-transplanted onion production (cv. Hybrid Yellow Granex PRR). CGM was applied at 4 rates (1000, 2000, 3000, and 4000 kg•ha**-1). No phytotoxic symptoms or yield reductions were observed due to either the CGM or the synthetic herbicide applications. The highest CGM rate (4000 kg•ha**-1) gave fair, 72.1%, total weed control and good, 82.7%, broadleaf weed control until 46 days after planting (DAP), whereas the synthetic herbicide treatments resulted in significantly greater weed control at 46 DAP and at harvest compared to all CGM application rates. Pendimethalin provided the best early and full season weed control. Increased weed competition caused a shift in bulb size distribution across the four categories (colossal, large, medium, and small), resulting in a decreased number of colossal and large bulbs and an increase in small bulbs. Although the CGM and synthetic herbicides provided crop safety, and to some extent early weed control, reductions in crop yields as a result of weed competition indicate the need to supplement postemergence herbicides with other weed control methods in order to minimize onion yield losses to weeds.