CCS HAU Rice Research Station, Kaul-136 021
National Symposium on Strategic Issues in Plant Pathological Research held at Department of Plant Pathology, CSK HP Krishi Vishvavidayalaya, Palampur on November 24–25, 2011
Sheath blight of rice (Oryza sativa L.) caused by Rhizoctonia solani Kuhn, earlier considered to be minor, has now attained the status of a major disease in Haryana. The roving surveys conducted in paddy growing areas indicated that the severity of the disease increased after 1995, particularly after 2005. During Kharif 2010, the disease appeared in severe form particularly in PR 114, CSR 30 and Pusa Basmati-4 and the symptoms of sheath blight were observed upto flag leaves with abundant fungal sclerotia and discoloured/chaffy grains, resulting in lodging and withering of the crop in patches resembling hopper burn patches in extreme cases. Out of 26 weed species tested, 22 were found to be infected by sheath blight pathogen on artificial inoculation while four weeds viz. Erigeron sp. (Horse weed), Ipomea aquatica (Ivy-leaved morning glory/Sarnali), Calotropis procera (Swallow wort/Madar/Ak) and Aeschynomeme indica (Indian joint vetch) were not infected. Among the infected weed species, E. crusgalli, E. colona, C. dactylon, D. aegypticum were observed to be naturally infected by R. solani. Euphorbia microphylla, Cassia sp. Dicanthium annulatum, Caesulia axillaris, Sida sp., Xanthium strumarium, Parthenium hysterophorus, Euphorbia hirta, Leptochloa panicea, Chenopodium album and Trianthema portulacastrum have been reported as hosts of R. solani for the first time.
