Integrated weed management in maize

Abstract

The corn plant is one of nature’s most amazing energy-storing devices. Weed management is one of the important practices for successful corn production. Herbicide-resistant corn hybrids (including glyphosate-, glufosinate-, and imidazolinone-resistant) have been adopted by corn producers primarily in the Americas. Glyphosate-resistant corn is the most widely grown herbicide-resistant variety by corn producers. This technology has provided excellent weed control for a decade; however, continuous and multiple applications of glyphosate in the corn–soybean cropping system have resulted in weed shifts and evolved glyphosate-resistant weed biotypes. This is the best example of negative implication of relying on a single method of weed control for many years. A well-planned weed management program in corn should involve multiple strategies, including preventive techniques, such as monitoring, cultural control, mechanical or physical control, and chemical control tactics. Preventive techniques may start with planting weed-free crop seeds or choosing an alternative field. Rotating crops to disrupt pest life cycles and planting adapted varieties are good examples of cultural control. Mechanical or physical control may include tillage and mowing to disrupt certain hard-to-control and perennial weeds. Flaming for weed control has been receiving attention of several corn producers in North Central USA and Europe, and it can be an important tool in an integrated weed management program. Use of herbicides is still the primary, efficient, and the most economical way for weed control in corn, but their use should be based on a sound management decision and rotation. Several existing corn herbicides have been tank-mixed or sold as premixed. They have been used extensively for control of herbicide-resistant weeds. Multiple herbicide-resistant corn (glyphosate plus 2,4-dichlorophenoxyacetic acid resistant; glyphosate plus glufosinate plus 2,4-D resistant) has been developed by industry and currently pending regulatory approval. Upon commercialization (once all regulatory approvals are secured), they may be effective for control of herbicide-resistant weeds; however, continuous use of the same trait and herbicides may promote evolution of multiple herbicide-resistant weeds.