The first official hemp crop in Louisiana is off to a rocky start. Many of the plants in the state are being hit by southern blight, a fungal disease. A soil-borne fungus called Sclerotium rolfsii is to blame for the problems.
“The pathogen has a wide host range and is known to cause disease on more than 500 plant species in 100 plant families,” Raj Singh, an LSY Ag Center plant doctor, said. “Some of the economically important vegetables include tomatoes, potatoes, peppers, eggplants, and cucurbits.”
With hemp, the plants will start to wilt and then turn brown and die off. Another sign is that the plants will have mycelium of the fungus and sclerotia at the base of the plant at the soil line as well as water-soaked legions. Even without a viable host, the fungus can survive in infected soil for several years.
There are many ways for the fungus to make it to the field. Infected plants could be planted initially, infested soil could be moved in, as well as equipment, tool, and debris. Even the irrigation water can spread the fungi.
“Management of southern blight warrants an integrated disease management approach,” said Singn. “Growers must plant disease-free, healthy transplants and avoid physical injury to roots and lower stems while handling and transplanting the seedlings.”
There isn’t even a fungicide that is effective, farmers are stuck working around the disease and being careful not to let is spread.