<p>Three different bio-elicitors viz. BE 1, BE 2 and BE 3 were formulated from <i>Fusarium oxysporum</i> f. sp. <i>lycopersici.</i> All three elicitors were screened for defence regulating capacity in an <i>ex vivo</i> system where <i>Lycopersicum esculentum</i> was used as a model host plant. Application of bio-elicitors on detached leaves showed varied degrees of defence induction and antioxidative enzymes and total phenol accumulation after 24 h incubation. Among all, BE 3 (2%) was found to be the most effective. Furthermore, production of nitric oxide (NO) was measured in treated leaves, and concurrently, the extent of oxidative damage was evaluated by measuring reactive oxygen species (ROS), malondialdehyde (MDA), proline and total chlorophyll content. All bio-elicitors except BE 3, which was effective at concentrations as low as 2%, showed enhanced production of MDA and proline and reduction in total chlorophyll at higher concentrations. These results suggest that among three elicitors tested, BE 3 (2%) can be used as a potential bio-elicitor in organic tomato farming.</p
