Glyphosate-resistant Volunteer Maize (zea Mays L.): Impact and Management

The United States is the largest producer of maize in the world. Maize-soybean is the most prominent crop rotation in the Midwestern United States. Glyphosate-resistant volunteer maize is a problem weed not only in soybean, but also in continuous maize or sugarbeet rotations. Storm damage, harvesting problems, poor stalk quality, and insect damage, among other factors, can lead to kernel and ear losses that result in volunteer maize the following year. Volunteer maize results from the overwintering of the hybrid maize used the previous year or from failed maize stand in maize replant situation. Increased adoption of glyphosate-resistant maize resulted in increasing issues of volunteer maize. Volunteer maize also plays a role in the survival and dispersal of corn rootworm and gray leaf spot disease; therefore, it limits the benefits of maize-soybean rotation and creates challenges for insect-resistance management. Management of glyphosate-resistant volunteer maize in soybean is complicated because growers are primarily relying on glyphosate for weed control. The acetyl-coenzyme A carboxylase (ACCase) inhibiting-herbicides, also known as graminicides, are often used to control volunteer maize in soybean. Several pre-emergence herbicides exist for residual grass weed control in soybean; however, none of them provides acceptable control of volunteer * Corresponding author’s email: [email protected]. Complimentary Contributor Copy Parminder S. Chahal, Prashant Jha, Tamra Jackson-Ziems et al. 84 maize. Glufosinate is an alternate herbicide that can be applied alone or in combination with ACCase inhibitors for control of glyphosate-resistant volunteer maize in glufosinateresistant soybean. The commercialization of multiple herbicide-resistant maize hybrids may pose new challenges for management of volunteer maize.