Septoria leaf spot, caused by Septoria cannabis, is a common disease of field-grown hemp (Cannabis sativa L.) in New York. Symptoms include brown lesions with yellow halos on the adaxial leaf surface that cause defoliation in severe infections. This report evaluates the efficacy of fungicides for the management of Septoria leaf spot on hemp. The trial was conducted in 2025 in Geneva, NY on hemp cultivar ‘Magic Bullet 5’. Results from this trial will help advise New York hemp growers in developing management programs for this disease.
Schwartz et al. (Mon,) studied this question.