| The nematophagous fungus, Paecilomyces lilacinus is one of the most promising fungal species that is employed for control of plant parasitic nematodes. A carbendazim-resistanted isolate of P. lilacinus strain PL221, was used throughout the study. The parasitic capacity of PL221 to Heterodera avenae have been studied under laboratory conditions, we also selected an optimum PL221 liquid culture for solid state fermentation (SSF). The carriers which were used for containing PL221 biomass, were screened out, and granular inoculants were then developed preliminary. Meanwhile, the granular inoculants were evaluated for their protection of wheat against H. avenae in field experiments.The parasitic capacity of PL221 to eggs of H. avenae and tanned cysts of H. avenae were studied in vitro under laboratory conditions, the results showed that the percentage of mixed eggs of all stages, including those in embryonic and those containing unhatched juveniles, infected by P. lilacinus strain PL221 is 61.01% 10d after inoculation. The egg surface was surrounded by extensive networks of PL221 hyphae in early phases, then the egg contents were consumed finally. The tanned cysts of H. avenae were inoculated and monitored with light microscope for 17d continuously, we also found that the cyst were surrounded by networks of PL221 hyphae, However, the eggs in the cyst were stained both with lactophenol-cotton blue and lactic acid glycerol, then examined with a light microscope, show that the eggs were not infected, and suggest that PL221 only grow on the surface of cysts but not infected them.The optimum liquid media were selected, both PDB and Czapek’s PL221 liquid seeds were used for solid state fermentation (SSF). The optimum seed age of PDB liquid seed for SSF is 60h, and inoculum 20%, the conidial content of the inoculum production was up to 7.28×109 conidia/g after 12d inoculated and fermented. The optimum seed age of Czapek’s liquid seed for SSF is 60h, and inoculum 15%, the conidial content of the inoculum production was 6.99×109 conidia/g after inoculated and fermented for 12d.Granular inoculants were developed preliminary. The component of granular inoculant, such as carriers and binder were screened out, and the ingredients were mixed and granulated. The production granular inoculant PLC grew vigorously from the granules and the initial population densities were 8.33×107 cfu/g, and became 7.43×107cfu/g when they were stored in darkness at 25℃for 6 months.The field trial of the granular formulation of inoculants of Paecilomyces lilacinus were carried out to control Cereal Cyst Nematode (CCN) on wheat. The result showed that both four different concentrations of granular inoculants and 5% of the Aldicarb treatment were significant difference with the control. The control efficacy on CCN at wheat seedling stage and early flowering stage with 75kg/ha was 30.9% and 31.96%, respectively, and caused significant reductions in number of cysts in the soil of 49.11%at harvest time, the overall control efficacy of 75kg/ha treatment was equivalent to 5% Aldicarb. The greatest control efficacy was achieved when 100g granular formulation of inoculants were applied in the plot. The control efficacy on CCN at wheat seedling stage and early flowering stage was up to 57.25% and 40.22%, respectively, and the reduction of the number of cysts was 59.82% at harvest time. However, the control efficacy of 25kg/ha and 50kg/ha treatments were significantly lower, only 20.12% and 14.25% at the wheat seedling stage,14.43% and 18.56% at early flowering stage, respectively. And the reduction of the number of cysts at harvest time was 18.75% and 13.39%, respectively. The field test results showed that the granular formulation of inoculants of Paecilomyces lilacinus can control the CCN effectively when appropriate dose of granules were applied in the soil. |
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