Effect of Trichoderma asperellum Samuels, Lieckfeldt and Nirenberg strains on the development of tomato and Meloidogyne incognita (Kofoid and White) Chitwood population

摘要

The objective of this study was to determine the potential of strains of Trichoderma asperellum, Lieckfeldt & Nirenberg to control M. incognita, (Kofoid and White) Chitwood. Under laboratory conditions (in vitro), six native strains of T. asperellum (Ta.25, Ta.1, Ta.90, Ta.78, Ta.79, and T.13) were selected for their high antagonistic capability, production of various metabolites, and adaptation to different environmental conditions and substrates. For the in vitro trial, 1/10, 1/25, 1/50 dilutions and the pure filtrate of each strain were tested, including a control treatment with sterile water. For the study under semi-controlled conditions, tomato (Solanum lycopersicum L.) plants were inoculated with 2.5 second instar juveniles (J) per gram of soil and, after 72 hours, 107CFU of the strain Ta.90 were added per pot The treatments were: healthy plants (absolute control), plants + Ta.90, plants +Ta.90 + nematodes, plants + nematodes, and nematodes + Ta.90 (without plants). The parameters evaluated after 35 days were galling index (IA), number of eggs per root system, plant height, stem diameter, root length, number of leaves, and weight of fresh root. High mortality levels were shown by all the T. asperellum strain filtrates; the strain Ta.90 stood out with 90% mortality at 24 hours. In the pot trial, this latter strain significantly reduced the number of eggs per female compared with the unapplied control, and attenuated the effect of the nematode on parameters such as plant height, stem diameter, number of leaves, and root fresh weight.