[Parasitic and lethal action of Trichoderma longibrachiatum against Heterodera avenae].

OBJECTIVE: To evaluate the potential of Trichoderma longibrachiatum spore suspension against Heterodera avenae.
METHODS: The parasitic and lethal effects of T. longibrachiatum spore suspension against the cysts of H. avenae were studied in vitro and observed under microscope.
RESULTS: Microscopic observation showed that the spore suspension of T. longibrachiatum parasitized on the cyst surface, germinated a large number of hyphae, and grew on the surface of the cyst at the initial stage. Later, the cysts were completely surrounded by dense mycelium, and the contents of digestion in cysts was lysed, even some cysts produced vacuoles, and some were split up and finally the cyst was dissolved by the metabolite of T. longibrachiatum. In vitro studies showed that high concentrations of T. longibrachiatum spores had strong parasitic and lethal effects on the cysts of H. avenae, and the probable mechanism of parasitic and lethal effects of T. longibrachiatum against H. avenae were mainly by inducing and increasing chitinase, glucanase and caseinase activity. The cysts were parasitized by 93.3% at 18 days, the hatching of cysts were inhibited by 93.6% at 10 days when treated with the concentrations (1.5 x 10(8) CFU/mL) of T. longibrachiatum.
CONCLUSION: Trichoderma longibrachiatum had strong parasitic and lethal effects on the cysts of H. avenae, and has the potential as a new biocontrol agent.