Septoria Leaf Spot: Caused by Septoria cannabis, this disease causes brown to black irregular spots with wide yellow halos. Spots rapidly coalesce and then leaves rapidly turn yellow and drop. Disease progresses from lower canopy upward. Septoria leaf spot develops early in the growing season and tapers off in hot conditions. Despite high severity on some floral cultivars, yield loss has not been documented. No other hosts have been identified.
