Begonia - Web blight (Rhizoctonia)

Web blight on Begonia caused by Rhizoctonia

Rhizoctonia is a natural inhabitant of the soil and can survive there indefinitely. The pathogen is widely distributed, has a wide host range, and causes diseases such as damping-off, root rot, crown rot, stem cankers, and web blight. This fungus prefers dry soil and is more active in the upper portion of the soil. It is easily introduced into the growth medium by soiled hands, tools,flats, and colonized transplants. Keep hose-ends off floors as Rhizoctonia can persist in dirt and debris on concrete floors. Fungus gnats and shore flies may introduce and spread this fungus within a crop. Biological and chemical methods are available for controlling these insects. Use soil-less growing medium and clean pots and flats. Fungicides for the control of Rhizoctonia include Banrot, Cleary’s 3336, Compass, 26 GT,26/36, Heritage, Sextant,Contrast, Defend, FungoFlo, Medallion, Terraclor, and Terraguard.

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