Author(s): Getahun Dereje*
Effective weed control in corn (Zea mays L.) is important to optimize yield. Excluding environmental variables, yield losses in corn are caused mainly by competition with weeds. Weed interference is a severe problem in maize, especially in the early part of the growing season, due to slow early growth rate and wide row spacing. Weeds compete with the maize plants for resources such as light, nutrients, space, and moisture that influence the morphology and phenology of crop, reduce the yield, make harvesting difficult, and mar the quality of grains. In order to realize the yield potential of maize, weed management becomes indispensable. Weed species infesting the maize crop are functions of a complex interaction among soil characteristics, climate, and cultural practices. A number of weed species compete with corn plant and have been observed to reduce yield as much as 30%-93% with delay in weed control. Weed species, densities, and their interactions influence maize yield loss. Effective weed management continues to be important in obtaining optimum corn yields. Integrated Weed Management is an important component of Integrated Pest Management (IWM), which is a holistic approach to sustainable agriculture focusing on managing insects, weeds and diseases through a combination of physical, cultural, biological and chemical measures that are cost effective, environmentally sound, and socially acceptable. A successful IWM program must include prevention of weeds from invading, knowing the identity and details of the weed species, mapping its distribution and damage, formulating control strategy based on knowledge of potential damage, cost of control method, and environmental impact of the weed, using a combination of control strategies to reduce the weed population to an acceptable level, and, finally, evaluating its effectiveness. All those weed management strategies are typically grouped into five categories: Preventive, cultural, mechanical (physical), biological, and chemical. No weed management technology used alone is sustainable since weeds will adapt to any single tactic used repeatedly for many years. Therefore, an IWM approach is required for sustainable corn production to meet the growing demand.
