Control of culex pipiens (Diptera: Culicidae), the vector of lymphatic filariasis, using irradiated and non-irradiated entomopathogenic nematode, steinernema scapterisci (rhabditida: Steinernematidae)

Abstract

The goal of this work was to investigate the effect of gamma irradiated entomopathogenic nematode EPN; Steinernema scapterisci on third and fourth larval instars of Culex pipiens under laboratory conditions and its effect on the elemental composition of the treated larvae. Results showed that normal and irradiated tested nematodes differed in their efficacies against third and fourth larval instars. The mortality rates increased with increasing the nematode concentration and the period after treatment, in most cases the mortality in fourth instar larvae was more than in third instar larvae under the same treatments, and the percentage of mortality in irradiated nematodes was more than that in unirradiated ones. Studying the elemental composition showed that phosphorus (P) was the highest concentration in untreated larvae or those treated with normal S. scapterisci, while calcium (Ca) was the highest concentration in gamma irradiated S. scapterisci. The lowest concentration in untreated larvae was zinc (Zn), while copper (Cu) was the lowest concentration in unirradiated and 2 Gy gamma irradiated S. scapterisci. In conclusion, the gamma irradiation of S. scapterisci enhanced its efficacy against C. pipiens, therefore it could serve as safe control method for C. pipiens.