| The Entomophthoralean fungus, Pandora nouryi Humber, belongs to Zygomycota and Zygomycetes. It is an important pathogen-infecting aphid in nature. It can causes epizootics in the populations of the green peach aphid, Myzus persicae, infesting cruciferous vegetables, during spring and autumn. The infecting rate of P. nouryi can reach 49.1% in nature. This dissertation presents data on the biological and infective aspects of the fungus-aphid association, including features of growth and sporulation in vitro, virulence, and interactions between the fungus and the aphid species at regimes of varying temperature and relative humidity (RH). It attempts to evaluate the potential of P. nouryi for use in microbial control of aphides.1. The present paper reported the results of the biological study of Pandora nouryi Humber strain. On the basis of the obtained results of the experiment, it was proved that the conidia could germinate only at high relative humidity (RH). At 95% of RH there is almost no germination. The conidia germinated faster at 100% than 97.5% of RH. The conidia germinated at the temperature from 15℃ to 25℃. At 30℃ there was no germination. The results also showed that the ultraviolet ray could kill the conidia. The range of pH for spores germination was 8~11, the optimum range was 9~10.2. Our study showed that the optimum culture of Pandora nouryi is SEA culture (peptone 10g/l,glucose 40g/l,agar 18g/l,yeast extract 10g/l,5 yolk,some antibiotic). The optimum carbon source and nitrogen source are glucose, peptone, respectively.3. Studies of the invasive and development process of Pandora nouryi Humber strain in the green peach aphid, Myzus persicae, had been done by using paraffine wax microtome technology. The conidium landing on the surface of an aphid host can germinate and produce a germ tube under suitable condition. After succeeded in breaching the host cuticle, the fungus formed protoplasts that had no cell walls, multiplied rapidly in the haemocoel and in tissue. As soon as the protoplasts filled with the host haemocoel completely, they began to prolong and form cell wall, thenturned into hyphal body. Thereafter, hyphal body filled up with the host body cavity and conidiophores broke through the host cuticle. This test made sure that P. nouryi multiplied in tissue of the host aphid in the form of protoplasts, and the process of invasion could be divided into four periods. These phenomenons were first reported in the world. It was found that the strain could produce protease and chitinase in inducing medium.4. Bioassay of the strain against Myzus persicae (1～2 instar nymphs) by using "spore shower" (20℃,12L/12D). Eight spore dosages were used to inoculate among 80~121 nymphaes. The resulting data were analyzed by using a time-dose-mortality (TDM) modeling technique, yielding the parameters for time and dose effect of the strain , the estimates of LD50 4～7 d after the spore shower were 55.92,8.96,5.61,3.95 conidia/mm2 respectively. Meanwhile the author had pointed out three manners of Pandora nouryi Humber attacking aphid under different spore dosages.5. The results showed that all the 17 insecticides had dramatic effect on the growth of Pandora nouryi Humber (P<0.01). In the 10 pesticides, the restrain rate of imidacloprid was 100%. The amount of spores produced in 1h on different culture medias with different pesticides showed that the spores produced by the colonies of imidacloprid were 0. On the contrary, the restrain rate of indoxacarb was 15.78%, the spores produced by the colony of indoxacarb were closed to the control. In the 7 fungicides the restrain rate of mancozeb was 100%. The amount of spores produced in 1h on different culture medias with different fungicides showed that the spores produced by the colonies of mancozeb were 0. The restrain rate of diethofencarb was the lowest, 31.51%. However, the spores produced by the colony of diethofencarb were only the one third of the control.
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