Theilaviopsis Root Rot. In: Compendium of Pea Diseases and Pests

Authors: HARMAN, G - Cornell University; Porter, Lyndon

Submitted to: American Phytopathological Society Press
Publication Type: Book / Chapter
Publication Acceptance Date: 7/17/2020
Publication Date: N/A
Citation: N/A

Interpretive Summary: Thielaviopsis root rot, also called black root rot, caused by Thielaviopsis basicola, is a disease reported to cause severe root rot in pea growing regions across the U.S. It has a wide host range infecting many different species of crops. The symptoms appear as dark brown to black elongated lesions on roots. Infected plants are usually chlorotic and stunted. The fungus produces both endoconidia and chlamydospores. Endoconidia are short-lived, while chlamydospores are the survival spores and are abundantly produced in infected tissue. Root infections are often associated with other root rots forming a root rot complex. Infection is favored by high soil moisture and temperatures. The pathogen is disseminated by movement of infested soil and infected plant tissue, colonized debris, water and farm equipment. Rye in crop rotations has shown to have a suppressive effect on T. basicola populations in soil. Soil fungicides and fumigants to manage the pathogen are generally not considered economically feasible, although fumigants and selective fungicides have been effective against the pathogen. Genetic resistance to this pathogen has not been identified.

Technical Abstract: Thielaviopsis root rot, also called black root rot, caused by Thielaviopsis basicola, is a disease reported to cause severe root rot in pea growing regions across the U.S. It has a wide host range infecting many different species of crops. The symptoms appear as dark brown to black elongated lesions on roots. Infected plants are usually chlorotic and stunted. The fungus produces both endoconidia and chlamydospores. Endoconidia are short-lived, while chlamydospores are the survival spores and are abundantly produced in infected tissue. Root infections are often associated with other root rots forming a root rot complex. Infection is favored by high soil moisture and temperatures. The pathogen is disseminated by movement of infested soil and infected plant tissue, colonized debris, water and farm equipment. Rye in crop rotations has shown to have a suppressive effect on T. basicola populations in soil. Soil fungicides and fumigants to manage the pathogen are generally not considered economically feasible, although fumigants and selective fungicides have been effective against the pathogen. Genetic resistance to this pathogen has not been identified.