Effect of Pre-Emergent Herbicide Applications on Environmentally Stressed Cotton

As weed populations with natural resistance to glyphosate have increased and spread, the need for pre-emergent herbicides has again become evident.  Under periods of stress, such as may be observed under extreme early or late plantings, young cotton plants may be exposed to doses of herbicides deemed safe under ‘normal’ conditions. 

Will McCarty, Mississippi State University Cotton Extension Specialist, wrote in 2002 that “all pre-emergence herbicides can damage young cotton or reduce or destroy a stand if a high concentration of the herbicide comes in contact with the germinating seed or young seedling. Tolerance depends upon soil type, organic matter content and amount and timeliness of rainfall the first two weeks after planting.” Vigorous  early season growth is necessary for early fruiting and early crop maturation.