Alternaria Leaf Spot of Cotton
Published: 08/18/2023
Alternaria leaf spot of cotton is a fungal disease caused by multiple species of Alternaria. It is commonly observed later in the growing season but may develop earlier under favorable conditions. Symptoms include small circular lesions with tan to brown centers and purple margins. The disease can be more severe in plants with nutrient imbalances, especially potassium deficiency.
Foliar symptoms of Alternaria leaf blight of cotton.
Travis Faske
Management strategies include burying infested crop residues, acid-delinting seed, and applying pre-plant potassium (potash). Fungicides are effective, but rarely economically beneficial.
Written and reviewed by Travis Faske, University of Arkansas; Tom Allen, Mississippi State University; Trey Price, Louisiana State University; and Terry Spurlock, University of Arkansas.
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