Meloidogyne incognita is one of the most important soil-borne and plant parasitic pathogens in cucumber
worldwide. An ideal strategy is to develop and use effective and environmentally-friendly bio-control
agents to control the plant parasitic pathogen M. incognita. This study determined the biocontrol efficacy
of Trichoderma longibrachiatum, a fungal species native to China, against M. incognita. In vitro,
T. longibrachiatum at the concentrations of 1.5 105 to 1.5 107 conidia ml1 had a strong lethal and
parasitic effect on the second stage juveniles of M. incognita, with the concentration of 1.5 107
conidia ml1 inhibited and parasitized the second stage juveniles >88% 14 days after treatments.
Microscope observations revealed that after the mutual recognition with the second stage juveniles, the
conidia of T. longibrachiatum adhered or parasitized on the surface of second stage juveniles, germinated
with a large number of hyphae and penetrated the integument, and was reproduced on the surface of
second stage juveniles. Meanwhile, the surface of second stage juveniles became deformed and some
were completely dissolved by the metabolite of T. longibrachiatum. The maximum protease activity of
T. longibrachiatum was 3.35 Umin1 ml1 at the 5th day after the treatment of second stage juveniles. In
greenhouse experiments, the concentrations of T. longibrachiatum ranging from 1.5 105 to 1.5 107
conidia ml1 all decreased M. incognita infection and increased plant height, root length, shoot and root
fresh weights in cucumber significantly compared to the control. T. longibrachiatum can be considered to
be a promising bio-control agent against M. incognita with a high efficacy.
ã 2015 Elsevier B.V. All rights reserved.