28 May 2013

Herbicide Injury

PS: Under field conditions, it is possible to confuse some nutrient deficiencies with certain herbicide injury effects. Additional information on field history and management practices will be needed to help identify the condition.

2,4-D and other related hormonal herbicides (e.g. quinclorac, triclopyr) may cause leaf elongation, irregular veins, and crinkled and curled leaf ends with downward cupping. Leaf color may stay a fairly normal green, but there will be abnormal swelling of the stalk right at the soil line.

Glyphosate injury results in an overall yellowing of cotton plants, with a tendency for the leaf veins to remain green and the stalk to redden. Transient chlorotic symptoms may also occur on transgenic, glyphosate-resistant cultivars.

Dinitroanaline (e.g., pendimethalin) injury causes short, stunted plants with normal color, but with branches and leaves appearing stacked because of shortened internodes. Roots may appear pruned, with few laterals.

Prometryn injury tends to cause discoloration between leaf veins, while the veins themselves remain green. A complete field history is often necessary to accurately diagnose symptoms which may be easily confused with nutritional disorders.

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