MONITORING AND BIOCONTROL OF PADDY FUNGAL PATHOGENS COLLECTED FROM HASSAN DISTRICT

Abstract

ABSTRACT Rice or paddy (Oryza sativa L.), one of the staple food crops of 60% of world’s population, suffers from different kinds of diseases caused by fungi, bacteria, viruses, nematodes and other non-parasitic disorders. In the present study, four paddy samples were collected from different places of Hassan District, Karnataka, India and screened for fungal pathogens using Agar plate method. Results showed varied Disease Incidence in collected samples ranging from 52 to 85%. The variety BT collected from Sarguru showed a minimum DI of 52% whereas Rajmudi-sanna collected from Doddamagge showed 85% of maximum of total DI, followed by Dappa batha from Basavapatna (74%) and Rajmudi-Dappa from Handrangi which showed 60% DI. The Individual DI of different pathogens, such as Penicillium, Fusarium , Aspergillus niger and Aspergillus ochraceus in all the four samples have been recorded. Aspergillus niger was the major fungus found in all the four samples. The pathogen Aspergillus niger isolated from all the varieties was subjected to inhibition assay using leaf and stem extract of Leucas aspera L and Datura stramonium L which showed encouraging results in controlling the pathogen. Among these two plants, Datura stramonium controlled the fungal growth to the greater extent when compared to Leucas aspera. Among the plant parts selected for study, stem would a ideal for extraction of antifungal metabolite study. Aspergillus niger isolated from both varieties, Rajmudi-sanna and Dappabatha was controlled effectively by using stem and leaf extract of both Datura stramonium and Leucas aspera. Our results suggested that for extraction of metabolites, solvents such as alcohol and acetone at 50 or 70% can be effectively employed. Dosage dependent study results indicated that the solvent extract of 80 µl had given better results, so this concentration should be useful for inhibition assay.