Weed Control Strategies for Controlling Transgenic Herbicide Resistant Volunteer Corn.

Various stand establishment problems, including excessive soil moisture, seedling blights, hail, and frost, force farmers in Ohio to replant corn acreage in late May & early June. Replanting herbicide resistant corn hybrids is more complicated than replanting conventional hybrids. Volunteer corn with resistance to glyphosate and/or glufosinate herbicides may adversely affect the performance of replant corn. A study was conducted at S. Charleston Ohio in 2009-2010 to identify effective herbicide treatments for controlling herbicide resistant volunteer corn. A glyphosate resistant corn was planted in late April and replanted in late May with a glyphosate/glufosinate resistant corn hybrid. Eleven herbicide treatments were considered. In three treatments, glyphosate/non-glyphosate blends (50/50 or 25/75) were planted first and replanted with a glyphosate/glufosinate resistant corn hybrid. The results indicated that when pre-existing plants were allowed to grow, they adversely affected grain yields, and that several herbicide treatments were effective in controlling herbicide resistant volunteer corn.