Prevalence and distribution of rice blast disease in paddy growing areas at Pasir Puteh district, Kelantan / Raja Mohd Saifuldin Raja Mamat

Blast (Magnaporthe oryzae) disease is the one of the most important disease that affects the rice production in Pasir Puteh district, Kelantan. The present study that was carried out in order to identify the disease intensity and the characteristic of its causal agent in the rice field at Pasir Puteh district, Kelantan. The survey of the rice blast disease incidence was conducted in 15 farmer’s field in a same district during the rice cropping season which comprised of 5 localities such as Bukit Yong, Sungai Gali, Wakaf Bunut, Gong Datok and Tok Kamis. The results that obtained from the survey showed that the disease incidence and severity were different from low to high on the different rice fields which was depending on different rice variety and agro-ecological. The disease incidence of rice blast in 5 different localities were varies from 30.83% to 49.23%. The highest mean of disease incidence was recorded in Wakaf Bunut which was 49.23% and the lowest was recorded in Bukit Yong which was 30.83%. In addition, the blast severity revealed the same trend as the disease incidence in 5 different localities. The highest disease severity was recorded in Wakaf Bunut which was 45.78% while the lowest disease severity was recorded in Bukit Yong locality which is 25.33%. For the disease prevalence, the entire field in different localities showed 100% of blast disease prevalence. The rice blast pathogen was isolated to identify its characteristics on PDA medium after 7 days incubation period. After 7 days, the fungus of the rice blast disease appeared is grey in color, cottony texture, margin was irregular, and pigmentation was black. The result for conidia observation was done by using the microscope which to observe the microscopic characteristics of the fungus. The pathogenicity test which was done by using the detached leaves method to test the M.oryzae on the leaves of the rice has given the positive result for the infection development. The pathogenicity tests have proven by using the Koch’s postulates method that isolated M.oryzae was capable to infect local susceptible rice plants at Pasir Puteh district, Kelantan.