Abstract

Chitosan, chitosan hydrolysates and menadione sodium bisulphite (MSB) were applied to soil and sprayed on tomato plants in different sets of experiments, to evaluate their combined effects on disease development in tomato plants. In young plants, the three products were effective protecting plants against the disease, foliage sprays showing the best results with chitosan hydrolysates and MSB (0.25 + 0.05 g.L-1 respectively), suggesting that the induction of systemic resistance plays a major role as defense mechanism of tomato against Fusarium oxysporum f.sp lycopersicii (FOL) attack. Several enzymatic mechanisms related with host defense were measured in plants treated with elicitors and inoculated with FOL as markers for disease resistance.