Potential use of Trichoderma asperellum (Samuels, Liechfeldt et Nirenberg) T8a as a biological control agent against anthracnose in mango (Mangifera indica L.)

Twenty isolates of Trichoderma were obtained from orchards located in three main mango-producing States in Mexico: Chiapas, Oaxaca, and Michoacan, which represent different agronomical management practices and levels of soil fertility. Phylogenetic analysis showed that Trichoderma isolates belong to the following taxa: Hypocrea lixii (10 isolates), Hypocrea jecorina (four isolates), Trichoderma asperellum (three isolates), Trichoderma spirale (two isolates), and Trichoderma brevicompactum (one isolate). The genus Hypocrea is the teleomorph (sexual) stage of the genus Trichoderma, anamorph stage. Seventeen Trichoderma isolates showed at least 67% growth inhibition against the phytopathogenic fungus Colletotrichum gloeosporioides ATCC MYA 456 and three Trichoderma isolates showed complete overgrowth of this pathogen. One member of this group, identified as T. asperellum T8a, was able to control C. gloeosporioides ATCC MYA 456 in vitro and in vivo, as well as five C. gloeosporioides isolates obtained from mango orchards from the State of Oaxaca. Assay of the lytic enzymes involved suggest that cellulases of T. asperellum T8a play a role in biological control against C. gloeosporioides ATCC MYA 456 more than chitinase or glucanase. Thus, native T. asperellum T8a associated with mango trees can be used to enhance mango production, controlling anthracnose through cellulase activity.

Highlights► 20 Trichoderma isolates were obtained from mango orchards located in south Mexico. ► High soil fertility leads to smaller number of Trichoderma isolates. ► T. asperellum T8a is a biological control agent against C. gloeosporioides. ► Cellulases produced by the strain T8a degrade the mycelium of C. gloeosporioides. ► T. asperellum T8a can be used to enhance mango production.