Sheath blight of rice

[4] Infected plants develop circular or oblong lesions, usually green-gray and water-soaked, on their lower leaves, normally in the late tillering or early internode elongation stage of growth.

Under favorable conditions of high humidity and low sunlight, the lesions spread and reach the upper part of the plant using runner hyphae.

[5] Both the sclerotia and mycelia of Rhizoctonia solani overwinter in plant debris and in tropical environments where they can survive in weed hosts.

[citation needed] Studies show that some strains of bacteria, when applied to the rice seed before planting, decrease the viability of the sclerotia of R. solani, reducing instances of disease and increasing yield.

The pathogen then releases many cell wall degrading enzymes (CWDEs) that contribute to lesion formation and spread, including polygalacturonase, cellulase, pectin methylgalacturonase, and polygalacturonic acid trans-eliminase.