Biological control of fusarium wilt of tomato by antagonist fungi and cyanobacteria
Biological control of Fusarium oxysporum f. sp. lycopersici (FOL) causing wilt disease of tomato was studied in vitro as well as under pot conditions. Dual culture technique showed that Aspergillus niger, Penicillium citrinum, Penicillium sp. and Trichoderma harzianum inhibited the radial colony growth of the test pathogen. Methanol extract of Nostoc linckia and Phormidium autumnale showed moderate and minor zone of inhibition. Maximum seed germination was observed in seeds treated with N. linckia (93%), whereas, T. harzianum, P. autumnale, P. citrinum showed 80% seed germination, while A. niger treated seeds showed 50% germination. Under pot conditions, the plant heights, fresh and dry weight of plants were found to be increased significantly (p ≤ 0.05) in all treatments except in P. autumnale amended soil. Similar results were observed in chlorophyll (a+b) content of treated plants. Maximum control of wilt disease was observed with T. harzianum (44.4%) treated plants as compared to FOL inoculated plants. Whereas, effectiveness of the other antagonists were recorded in the following order: A. niger (35.6%), N. linckia (33.3%), P. citrinum (24.4%), and P. autumnale (0.9 %).
Key words: Biological control, fusarium wilt, tomato, antagonist fungi, cyanobacteria