Occurrence of rice blast disease caused by Magnaporthe oryzae B.Cauch in Jigawa State, Nigeria

Abstract

The aim of this research was to determine the presence of rice blast disease in the three major rice producing Local Government Areas of Jigawa state (Hadejia, Kaugama and Auyo) in 2020 (Rainy and Dry seasons) with the object of determining the incidence; distribution and severity of the disease. The survey was conducted two times; rainy season and dry season during which at least fifty one (51) rice fields (replicated two times) and selected purposively, were surveyed in each season for blast symptoms. Results of the survey have shown that the disease occurred at varying disease incidences (%) and severities. The disease symptoms appeared more on rice cultivated in Kaugama (16.3%) than in both Auyo (12.6%) and Hadejia (12.5%) Local Government Areas and more in the dry season than in the rainy season thus indicating a significant difference (p<0.05) in the study areas and across the seasons. However, careful observation on the agronomic practices in the three study areas have shown that about 50 % of the fields surveyed in Kaugama were weedy, poorly fertilized, waterlogged and with other disease symptoms such as blight and spots. This might have been the reason for the relatively higher incidence and severity of the disease in Kaugama rice fields. Farmers should be informed of the danger of abandoning rice fields to become bushy as this might cause the disease to escalate to an uncontrollable stage.