ISOLATION OF NATIVE STRAINS OF TRICHODERMA SPP, FROM HORTICULTURAL SOILS OF THE VALLEY OF TOLUCA, FOR POTENTIAL BIOCONTROL OF SCLEROTINIA

Abstract

The presence of Trichoderma mold strains was evaluated in seven localities in the southern part of the Valley of Toluca in the State of Mexico. This area has a high potential for growing vegetables. In the study, native strains of Trichoderma were isolated from soil samples, physiographic factors were identified, as well as the physicochemical properties of the soil which may affect Trichoderma occurrence. The potential of Trichoderma strains for control of Sclerotinia spp., a pathogenic fungus which causes soft rot in lettuce, was evaluated. Eleven strains were isolated, most of them associated with the type of soil found in the San Francisco Putla and San Francisco Tetetla localities. Logistic regression analysis showed no relationship between the soil properties (organic matter content and pH) and the presence of Trichoderma. Tukey test (p<0.05) showed significant differences between the percentage of inhibition of Sclerotinia by the eleven native strains of Trichoderma. The TF10, TL4 y TX8 strains had a high biocontrol potential, with inhibition percentages of 80%, 86% y 88%, respectively. These strains are an ecological alternative for the control of Sclerotinia spp.