Abstract

Indigenous fungi found associated with water hyacinth were identified and evaluated for their biocontrol potential against the weed. During the study, a series of laboratory and lath-house experiments were conducted and 19 fungal species were identified. Among these, nine species with better virulence were selected based on preliminary test. These included Alternaria alternata, Alternaria geophila, Ascochyta chartarum, Cochliobolus carbonum, Epicoccum nigrum, Fusarium chlamydosporium, Fusarium equiseti, Pythium ultimum and Stemphylium vesicarum. Accordingly, pathogencity test was carried out in RCBD design with three replications to select the best candidates and five of them were found to be virulent to water hyacinth with disease severity ranging from 4.33 to 5.67 in 1 to 6 disease severity rating scale. The five promising candidates were A. alternata, A. chartarum, F. chlamydosporium, F. equiseti and P. ultimum.The highest disease severity 5.67 was recorded by P. ultimum while the least severity with 4.33 was recorded by A. chartarum. Based on the current findings, we concluded that, A. alternata, A. chartarum, F. chlamydosporium, F. equiseti and P. ultimum could be used as effective biocontrol agents against water hyacinth following performance evaluation under natural environmental conditions and their host specificity test.

Key words: Biocontrol, indigenous fungi, virulent, pathogenecity.