| Entomopathogenic nematodes has been one of the most widely used biological pesticide in the past few years.It was indicated that nematode was an ideal pesticide for underground pest control,especially for the white grubs.Because of their biological control value,It was the representative of biological pesticides.Many highly pathogenic nematodes species had been screened and identified for field application. In order to obtain better application of entomopathogenic nematodes on controlling the white grubs in alpine areas,The composition and dynamics of soil pest in Lolium perenne+Poa pratensis+Festuca elata mixed lawn was analysed in Xining region in 2013;Virulence of S. longicaudum X-7 to white grubs larvae was determined at different infective dosage,different temperature,different time,different usage,instared in lab.The main results were shown as follows:(1)The species of soil pests in Xining lawn were consisted a larva of white grubs,Pleonomus canaliculatus and Euxoa segetum,which was mainly distributed in 0~10 cm soil layer.(2)The population densities of soil pests of Dopa and Biological park showed a increasing in may,reducing in August.The population density of a larvae of white grubs in this three sites was significantly higher than which of Pleonomus canaliculatus and Euxoa segetum(P< 0.05),and white grubs was the most serious pest in this region.(3)The S. longicaudum X-7 had strong virulence against white grubs 1st instar larvae and 2st instar.lethal time is mainly concentrated within 48 h. The nematode had low virulence against white grubs 3st instar larvae.At 25℃,virulence was the best. By increasing the dosage of nematodes,virulence were also increased.treating 2 times to control the soil pest was better,but was not better to 2st instar.(4)When the does is 3000 Ijs/m L,The mortality reaches to 73.33%,The fatality rate 0f pestcide is 80.85%and78.73%,63.33%,respectively.It is hopeful that nematodes subttitude pestcide. |
