First Report of Southern Blight of Industrial Hemp Caused by Athelia rolfsii in Louisiana

Abstract

Louisiana growers planted their first industrial hemp (Cannabis sativa L.) crop in 2020. A total of 932 licensed acres were planted, predominantly with CBD cultivars, for hemp fiber, extraction of plant resin, and grain and seed production. Between June and August of 2020, southern blight was reported from all major growing areas including Avoyelles, East Baton Rouge, Lafayette, Lincoln, and Rapides Parishes. Disease incidence and severity varied from 10 to 50% and from 30 to 90%, respectively. Based on morphological characteristics and sequence analysis, the fungus was identified as Athelia rolfsii (anamorph: Sclerotium rolfsii). To our knowledge, this is the first report of southern blight of industrial hemp caused by A. rolfsii in Louisiana.