Morphological and genetic characterization of Fusarium oxysporum and its management using weed extracts in cotton

Abstract

Fusarium oxysporum, a fungal plant pathogen, causes severe wilting and heavy losses in cotton. Present research was planned to appraise the weed extracts of Parthenium hysterophorus, Chenopodium album, Canada thistle and Phalaris minor against F. oxysporum. Morphological identification of F. oxysporum was done by observing white cottony mycelium with dark-purple undersurface on growth media and oval to ellipsoid/kidney shaped oval tapering and three septate spores. Molecular characterization was done by amplifying internal transcribed spacer region using the ITS universal primers, ITS1 and ITS4. The weed extract with concentrations of 5%, 10%, 15% and 20% were applied by using food poison techniques under complete randomized design. Data was taken 3, 5 and 7 days after inoculation of F. oxysporum on potato dextrose agar (PDA). P. hysterophorus showed maximum antifungal response (97%) against F. oxysporum whereas other treatments effectively inhibited the pathogen growth on PDA media. Tebuconazole, a fungicide, was used as positive control. Trichoderma harzianum showed 98% inhibition of F. oxysporum on PDA. Consortium of Trichoderma harzianum + weed extracts was applied in infected roots of cotton grown in pots under complete randomized design. No disease was observed in treatment P. hysterophorus + T. harzianum whereas maximum disease was calculated (50%) in other treatments as compared to control (100%).