Abstract

                                A rice field trial against the sheath rot pathogen was conducted at Paddy Breeding Station, Coimbatore. The study proved that sheath rot was incited by Sarocladium oryzae and not due to Fusarium which is a saprophyte organism. The involvement of insect pests viz., stemborer, leaf hoppers, earchead bug, leaf folder and mite in favoring the sheath rot infection was also proved. Among the insects stem borer paved the maximum way for the sheath rot infection followed by hoppers. The method of spread depicted that the pathogen spread was faster in a vertical manner (movement within the plant) followed by horizontal manner (plant to plant). The yield loss study also indicated that the reduction in growth parameters viz., plant height, healthy tillers/ hill and panicle length were 16.84,100 and 20.17 percent over control respectively. The loss in yield parameters viz., the per cent reduction in 1000 grain weight (11.22 percent over control) and grain yield (29.3 percent over control) were recorded in highly susceptible cultivar CO43.

Key words : Sarocladium oryzae, rice, yield loss, insect pests, disease spread