Limiting Green and Yellow Foxtail (Setaria viridisandS. glauca) Seed Production Following Spring Wheat (Triticum aestivum) Harvest

Abstract

Green and yellow foxtail seed production following harvest of spring wheat is a concern of producers in the northern Great Plains of the United States and the Prairie Provinces of Canada. Experiments were conducted in 1996 and 1997 in three tillage systems, no till (NT), chisel plow (CP), and moldboard plow (MP), at the University of Minnesota West Central Experiment Station, Morris, MN, to determine whether time of glyphosate application or tillage after spring wheat harvest could reduce postharvest foxtail seed production. In both years, hard red spring wheat was planted in late April and a packaged mixture of fenoxaprop and 2,4-D ester and MCPA ester was applied at a rate of 53 g and 81 g and 246 g ai/ha for grass and broadleaf weed control. Following spring wheat harvest, each main plot was subdivided into seven subplots, including an untreated control. One subplot was disked twice at 4 to 6 d after harvest (DAH) of spring wheat, and five other subplots had glyphosate (0.25 kg ai/ ha) applied on different days (1 to 31 DAH). Foxtail seeds were collected from the soil surface following first frost, and the number of green and yellow foxtail seeds were determined. Tillage immediately after spring wheat harvest eliminated foxtail plants, and no new foxtail seedlings emerged in either tilled or glyphosate-treated plots despite ideal postharvest conditions for foxtail germination and emergence in 1997. Most viable green foxtail seeds were consistently obtained in NT plots, whereas yellow foxtail seed production varied among tillage systems. Either tillage soon after spring wheat harvest or glyphosate application within 16 DAH reduced green and yellow foxtail seed production by greater than 70%.

Effects of Common Wheat (Triticum aestivum) Management Alternatives on Weed Seed Production1

“…Management treatments administered early in the growing season had little to no effect on foxtail seed production after spring wheat harvest, which mimics the results reported earlier (Kegode et al 1999). There are two interesting features regarding postharvest seed production.…”

“…For example, Kegode et al (1999) found that either tillage or glyphosate application within 10 d after wheat harvest lowered foxtail seed production considerably. Even though tillage after wheat harvest can result in burial of weed seeds, it also minimizes foxtail regeneration and consequently lowers the overall foxtail seedbank (Eyherabide and Calvino 2000).…”

“…In our study, foxtail seeds were dispersed twice: during spring wheat harvest; and later, after wheat harvest, when seeds were shed from late-growing plants. With this information, management strategies that are geared toward minimizing the number of weed seeds that are dispersed can be implemented, for example, using tillage or glyphosate after wheat harvest (Kegode et al 1999).…”

Tillage effect on reproductive output by foxtail cohorts in corn and soybean

“…Green foxtail and yellow foxtail are important weeds in many crops grown in North America, and they are known to produce numerous seeds (Kegode et al 1999a(Kegode et al , 1999b(Kegode et al , 2003Santelmann et al 1963;Vanden Born 1971). Because factors regulating foxtail seed production are poorly understood, there is a need to determine the magnitude of seed production of plants that escape control.…”

United States Department of Agriculture–Agricultural Research Service research on pest biology: weeds

“…This level of fecundity is more than enough to replenish the seedbank. Identical processes occur after spring wheat harvest in the Corn Belt with foxtails ( Setaria spp),62 and almost certainly they occur in all other cropped fields as well. In many instances lush maturing crops will hide smaller seed‐bearing weeds and, thereby, lull managers into a false sense of accomplishment.…”