In vitro biocontrol of tomato pathogens using antagonists isolated from chicken-manure vermicompost

The objectives of this study were to (1) isolate and identify pathogenic fungi from vegetative material with wilt symptoms in tomato plantations belonging to the Cienega of Chapala, Michoacán, Mexico, and (2) determine the antagonistic capacity of Trichoderma sp. and Aspergillus spp. isolated from chicken-manure vermicompost. Pathogens were isolated by means of a completely randomized sampling in 6 locations; 9 plantations were inspected and 45 plants with symptoms of the disease were selected. Portions of root and stem were disinfected and placed on potato-dextrose-agar acidifed (PDA). Antagonists isolation was made from a dilution of chicken-manure vermicompost of 1 × 10^-2 in PDA medium culture more streptomycin and tetracycline. Te antagonistic activity was tested by the dual culture confrontation methods. Two pathogens were obtained on tomato in the study area, Fusarium spp. and Rhizoctonia sp., presenting an incidence of 92% and 5%, respectively. Morphological characteristics were determined in cultivation of PDA. Molecular analysis identifed F. oxysporum, F. solani, F. subglutinans and Rhizoctonia sp. Of 11 isolates of chicken manure vermicompost, only Trichoderma sp. and Aspergillus sp., had signif-cant diferences (p≤0.05) with respect to the control. Inhibition of F. oxysporum growth ranged from 45% to 48%, and 24% to 27%, in presence of Trichoderma sp. and Aspergillus sp., respectively; these antagonistic species inhibited growth of Rhizoctonia sp. by 38% and 25%, respectively.