Marestail is one of the most widespread and troublesome weeds in Iowa croplands. It can grow to a height of 1.5 to 6 feet, produce up to 200,000 seeds, and can reduce soybean yields up to 80% if not controlled (Figure 1). Marestail seeds are light and disperse across landscapes with winds. Seeds have little dormancy and can germinate soon after seed shed. In general, 75% of seedlings germinate in fall, remain in rosette-stage until spring, begin stem elongation in April, and start flowering in July. About 25% of seeds germinate in the spring. Due to these unique biological characteristics and a prolonged emergence period, a comprehensive management program is necessary for marestail control.
Iowa State University
Jha, Prashant, "2020 Summary of Herbicide Evaluations for Marestail (Horseweed) Control in Soybean" (2021). Integrated Crop Management News. 2687.
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