THE INFLUENCE OF WEED MANAGEMENT IN WHEAT (TRITICUM-AESTIVUM) STUBBLEON WEED-CONTROL IN CORN (ZEA-MAYS)

The objectives of this study were to determine how the timing of weed management treatments in winter wheat stubble affects weed control the following season and to determine if spring herbicide rates in corn c an be reduced with appropriately timed stubble management practices. F ield studies were conducted at two sites in Ohio between 1993 and 1995 . Wheat stubble treatments consisted of glyphosate (0.84 kg ae/ha) plu s 2,4-D (0.38 kg ae/ha) applied in July, August, or September, or at a ll three timings, and a nontreated control. In the following season, s pring herbicide treatments consisted of a full rate of atrazine (1.7 k g ai/ha) plus alachlor (2.8 kg ai/ha) preemergence, a half rate of the se herbicides, or no spring herbicide treatment. Across all locations, a postharvest treatment of glyphosate plus 2,4-D followed by alachlor plus atrazine at half or full rates in the spring controlled all broa dleaf weeds, except giant ragweed, at least 88%. Giant foxtail control at three locations was at least 83% when a postharvest glyphosate plu s 2,4-D treatment was followed by spring applications of alachlor plus atrazine at half or full rates. Weed control in treatments without al achlor plus atrazine was variable, although broadleaf control from Jul y and August glyphosate plus 2,4-D applications was greater than from September applications. Where alachlor and atrazine were not applied, August was generally the best timing of herbicide applications to whea t stubble for reducing weed populations the following season.