Sclerotinia Rot ofOcimum sanctumand the Host Range of its Pathogen

Abstract

Sclerotinia rot of Ocimum sanctum caused by Sclerotinia sclerotiorum has been recorded for last three years during winter season (2011–2014) at Kalyani, Nadia, West Bengal. The disease appeared in first week of December and progress of the disease continued up to the end of February. Drooping of leaves in one or more young twigs was the first symptom of the disease. Light brown discolouration on the twig and presence of white sclerotia might be associated with the initial symptom. Gradually more and more twigs were affected followed by death and drying of the infected twigs. In humid condition, prominent cottony white mycelia developed on the affected tissue. Towards end of February many plants became dead. Black matured sclerotia were found on the dead branches. On artificial inoculation the causal organism, Sclerotinia sclerotiorum infected fifty plants indicating that the pathogen did not have host specificity. But susceptibility of seventeen plants (Capsicum annum var. grossum, Trichosanthes dioica, Cucurbita pepo, Abelmoschus esculentus, Raphanus sativus, Trigonella foenumgraecum, Amaranthus tricolor, Portulaca oleracea, Pachyrrhizus erosus, Ipomoea batatas, Lathyrus sativus, Ricinus communis, Allium sativum, Foeniculum vulgare, Carica papaya, Chrysanthemum indicum, Chenopodium album) is recorded first time in India.