English

Abstract

The use of municipal solid waste compost in agriculture has known a particular interest because of its favorable effects on soil, on cultures and on environment. Treatment of plants with compost or compost extract or even their root or foliar inoculation with Trichoderma harzianum Tcomp, isolated from compost, were the most three efficient treatments against three strains of Botrytis cinerea agent of gray mold of tomato. These treatments induced similar suppressive effects in term of severity for the three strains of B. cinerea (B2, Bf3 and BP1), ranging between 0.9 and 1.3 for B2, or between 1 and 1.3 for Bf3 or even between 1.1 and 1.2 for BP1. Conidia productions for these three treatments are also similar for the three strains of B. cinerea, ranging between 1.02 and 1.09 10 4 conidia / cm 2 for B2, or between 1.06 and 1.08 10 4 conidia / cm 2 for Bf3 or even between 1.13 and 1.27 10 4 conidia / cm 2 for Bp1. The antagonists used in this study have efficiently suppress gray mold of tomato to varying degrees according to the antagonist itself (Trichoderma harzianum or Ulocladium atrum) and also to the inoculation method for T. harzianum, since each strain acts using one or more modes of action. Thus, TH1 and Tcomp strains act primarily by inducing the SR (systemic resistance) and LR (local resistance). Ulocladium atrum isolated from compost reduced B. cinerea by direct inhibition of conidia production. Whereas for T. harzianum Ttom, other mechanisms are involved. The effect of compost on B. cinerea, which is a foliar pathogen, is unusual and is due to the induction of tomato systemic resistance plants that is associated with the presence of a population of T. harzianum Tcomp in this compost able to induce this systemic effect. However, unidentified chemical factors in compost are also responsible for this suppressive activity.