Trichoderma strains as growth promoters in Capsicum annuum and as biocontrol agents in Meloidogyne incognita

The Trichoderma species act as plant symbionts, decomposers of organic material, and as antagonists of root phytoparasites. To estimate the potential of four native strains of Trichoderma as growth promoters of Capsicum annuum L. and as biocontrol against root knot nematode Meloidogyne incognita (Kofoid and White) Chitwood, two bioassays in greenhouse were established. In one, the capacity of Trichoderma to promote initial growth of seedlings (36 d after planting, dap) was evaluated. In the other, the biocontrol of Trichoderma against M. incognita at 96 dap was also evaluated. The Trichoderma strains and the chemical fertilization treatment significantly promoted seedling growth at 36 dap (P = 0.01). With respect to the control, T. atroviride promoted greater height in the seedlings, while T. atroviride, T. virens and T. harzianum-C2 increased fresh weight in roots (60.14%) and both T. atroviride and T. harzianum-C2 produced up to 82.30% more dry root biomass. In biocontrol, the control plants registered the highest damage with galling indexes of 85.50% (P = 0.01). The lowest galling indexes were estimated with all the Trichoderma strains (21.60% to 35%). Trichoderma atroviride reduced egg production by 63% and the production of females by 14.36%, with respect to the oxamyl nematicide. Biocontrol of the nematode through the application of the Trichoderma strains favored growth of the plants in general. The fungal species studied show potential as growth promoting agents and as biocontrol agents M. incognita in C. annuum.