| As an important bio-control agent entomopathogentic nematodes(EPNs) are used widely for controlling agricultural and forest insect pest. In order to widen its usage range and enhance its desiccation tolerance then increase effect on pest, two studies were carried out, one in greenhouse of Liancheng town of Kaifeng city in He'nan province to explore the effect of entomopathogenic nematodes (EPNs) on soil nematode community structure in rhizosphere of cucumber and another to determine the effect of continuous generation desiccation induction under two regimes on desiccation tolerance and virulence of three nematodes isolate of Rhabditis sp.Eighteen genus in thirteen families in six orders were identified and divided into 5 trophic groups that are bactevores, entomopathogenic nemotodes,phytophages and omnivore predators.fungivores .and Among them Rhabditis and Peladera are the first records in He'nan.After finding possibility of EPNs suppressing plant nematodes, effect of EPNs on other trophic groups were further determined by applying EPNs to cucumber field. The result showed that both applying native strain and non-native isolate can increase EPNs population in soil much more and respectively by 1683 and 1224 per 100mL soil in April of 2005 while plant nematode population reduced respectively by 1285 and 1247 per 100mL soil. The native isolate showed better suppressing effect on plant nematodes than non-native strain did not work until the late growth stage of cucumber.Three EPN isolates of Rhabditis sp were inducted under two regimes, at 42% RH for 24h (Rapid induction) and first at 97% RH 72h then at 42 % RH for 24h (Gradual induction). The result indicated that twenty continuous generation induction under both regimes increased desiccation survival and virulence of induced nemotodes of three isolates, their desiccation tolerance fluctuated before the 13th generation and then trended stable. The last three generations showed stable and high desiccation tolerance. |
PDF Full Text Request