Separation And Cultivate Of Entomopathogenetic Nematodes And Preliminary Determination Of Its Pathogenicity

For find an entomopathogenic nematode strains that prevention and of treatment mushroom flies effective,isolated nematodes from more than 500 samples soil of collected from Xinjiang Yili and Urumqi area, and preliminarily screening isolated to nematode.Observe a strong pathogenicity to Drosophila and Tenebrio molitor of nematode strains(NLK-1). The mortality of infected with the nematode of Tenebrio molitor last instar larvae and Drosophila larvae was 92.6% and 89.3%,signif icantly higher than that of other kinds of entomopathogenic nematodes.Through the observation of the morphological characteristics of seven species of entomopathogenic nematodes, and measure the important parameters the infected of larvae,and showed that morphological characteristics of nematode NLK-1 was most similar with h.bacteriophora; At the same time, the results of 18S-r DNA sequences alignment and 16S-r RNA sequences alignment to symbiotic bacteria and phylogenetic analysis showed the population also had the closest genetic relationship with H. bacteriophora. Therefore, the population was identif ied as H. bacteriophora NLK-1 strain.Virulence of H. bacteriophora nlk-1 strain to Tenebrio molitor instar larvae was determined at different infective dosage and temperature in lab. It was confirmed that the mortality of larvae increased with dosage and with time dependent. The mortality at the doses of 250 IJs/mL, 400 IJs/mL all reached to 100% after infection of 60 h and 72 h respectively.In different temperature,Heterorhabditis NLK-1 infected Tenebrio molitor larvae suitable temperature between 20 ℃ ~30 ℃, The temperature treated at 25 ℃ and 30 ℃ were most in favour of infection, mortality rates were reached 85.7% and 96.4% after infected 96 h. In the suitable temperature range,Pathogenicity of the nematode to Tenebrio molitor b ecome higher with the increase of temperature,and can shorten the time of disease.Using three methods of mass cultivate Heterorhabditis NLK-1.The result showed,White trap method with tenebrio as host insects, for in vivo propagation, collecting nematode by nematodes collecting plate and harvest nematodes,infection rate of 92.6% and production of 2.47 x 105 IJs/g; Liquid Production technology using PSYG medium and TSYS medium nematodes to culture nematodes,harvest nematodes within 11-25 d, the production of nematodes TSYS medium is more, 17 d as the best time to harvest, infection rate of 77.8% and production of 1.52 x 105 IJs/mL; Solid sponge Production technology using PSYG medium and TSYS medium nematodes to culture nematode,harvest nematodes within 11-25 d,the production of nematodes PSYG medium is more,23 d as the best time to harvest, infection rate of 81.5% and production of 1.8 x 105 IJs/mL. Strongest nematodes ability to infect the host is white trap method, second liquid propagation method, third solid propagation method.