Importance of Trichoderma species for control of Macrophomina phaseolina in agricultural areas of Aragua state, Venezuela

Abstract

Fungi of the genus Trichoderma deserve maximum attention as biocontrol agents because they demonstrated their high antagonistic power plant pathogens. The objective of this research was to identify Trichoderma species isolated from soil samples of bean growing areas, corn, tomato and sorghum in Aragua, Carabobo and Guarico and the antagonistic value was found in the control of Macrophomina phaseolina. The samples were processed using the method of agar plate dilution, the isolates obtained were purified on PDA, its determination was performed at the species level. To do this, the isolates were grown for 3-4 d and 6-8 d being examined macro and microscopically. Twelve isolates were obtained, nine were related to the species Trichoderma harzianum (06146, 06143, FTSC05, JCFA05 , 06153, I9, J10, and San Miguel 06151); and the remaining isolates belong to the species T. crassum (06141), T. koningiopsis (06152) and T. longibrachiatum (Samán Mocho) respectively. Variability in vitro was found in the control exercised by each isolated against M. phaseolina, depending on the percent inhibition of sporulation (PIE) and growth inhibition (PIC). The isolated belonging to T. crassum 06141 was the most effective in controlling M. phaseolina, and showed higher PIE of 91.02% and 91.50% of PIC compared to other isolates, which had an inhibitory effect with respect to the fungal pathogen in the range of 65.09 to 84.69% for the PIE and 67.33 to 77.48 for the PIC.