Submitted to: Weed Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/30/2002
Publication Date: 12/1/2003
Citation: KEGODE, G., FORCELLA, F., DURGAN, B. EFFECTS OF COMMON WHEAT (TRITICUM AESTIVUM) MANAGEMENT ALTERNATIVES ON WEED SEED PRODUCTION. WEED TECHNOLOGY JOURNAL. 2003. V. 17. P. 764-769. Interpretive Summary: One of the keys to solving the seemingly endless battle of controlling foxtails (pigeon grass) in spring wheat in the northern Great Plains is prevention of foxtail seed production. For two years we examined the effects of wheat seeding date, tillage system, standard postemergence herbicide application, and post-harvest foxtail control on the production of seeds by green and yellow foxtails. Our results showed that foxtail seed production is reduced with early seeding of spring wheat, largely unaffected by tillage system, and reduced by application of postemergence grass herbicide. Once spring wheat is harvested, however, small foxtail plants under the wheat canopy rapidly develop, flower, and produce seeds. Regardless of the effects of the above-mentioned management practices, control of these late developing foxtails must occur within 10 days of spring wheat harvest if overall foxtail seed production is to be reduced. The importance of these results is that it underscores how foxtail seed production can be prevented and scores the management factors that regulate seed production in order of increasing importance: tillage system, early seeding, postemergence herbicide, and post-harvest control.
Technical Abstract: Research was conducted to determine the influence of tillage regime, date of wheat seeding, and postemergence herbicide application on foxtail plant density, plant height, panicle length, and viable seed production at and following wheat harvest. Hard red spring wheat was seeded in late-April (early), early-May (mid), and mid-May (late) into moldboard plow, chisel plow, and no-till plots in 1996 and 1997. At the 4-leaf stage of spring wheat, postemergence applications were made of fenoxaprop plus 2,4-D ester plus MCPA ester (FMT), for grass and broadleaf weed control, and 2,4-D ester for broadleaf weed control in comparative plots. Foxtail plant densities were influenced significantly by seeding date of wheat in 1996, by tillage regime in 1997, and by herbicide both years. FMT significantly reduced green and yellow foxtail plant height both years, whereas delayed seeding of wheat reduced foxtail plant heights in 1997. Application of FMT resulted in a significant reduction in panicle size of green foxtail in 1996 and of yellow foxtail both years. Green and yellow foxtail seed production at time of wheat harvest was reduced when FMT was applied but increased when wheat seeding was delayed. Treatments administered early in the season had little to no effect on foxtail seed production following wheat harvest. This study indicates the importance of early seeding of wheat and the application of postemergence herbicides in reducing foxtail plant density, height, panicle size, and seed production at time of wheat harvest. However, following spring wheat harvest, regardless of prior management, control of regenerating foxtails is necessary to prevent the production of viable seeds before the first killing frost.