In Manipur, onion species are screened for the white rot disease caused by Sclerotium rolfsii Sacc.

Abstract

Onion cultivations at many small-scale onion producing places in Manipur have been severely damaged by white rot caused by Sclerotium rolfsii. In all onion species, April had the highest incidence of white rot disease, whereas February had the lowest. For the first three months after planting, the disease's symptoms were not noticeable. During the second week of February, yellowing of the leaves began at the tips and progressively spread downward, indicating the presence of white rot. The illness became most noticeable during the final week of March and the first week of April, when the onion plant began to wilt and collapse and the basal portion of the stem began to rot and droop. The pathogen's symptoms, such as sclerotia and white mycelium, are present in the decomposing bulbs of infected plants.