Host stage preference in the parasitoid wasp, Eretmocerus delhiensis, for parasitism and host-feeding

The parasitoid wasp, Eretmocerus delhiensis Mani (Hym., Aphelinidae), is an active ecto-endo and solitary parasitoid in southwestern Iran. To evaluate Er. delhiensis as a biocontrol agent against the greenhouse whitefly, Trialeurodes vaporariorum (Westwood) (Hem., Aleyrodidae) its host stage preference for parasitism and host-feeding was investigated. In this study, choice (multiple-instar) and no-choice (single-instar) tests were conducted under laboratory standard conditions. The results of both tests indicated that Er. delhiensis fed on and parasitized all T. vaporariorum nymphal instars but preferred the 2nd and 3rd nymphal instars for host-feeding and parasitism, respectively. Moreover, it showed the highest and lowest development times were in the 3rd and 1st nymphal instars, respectively. According to our findings, parasitism of the parasitoid wasp, Er. delhiensis, along with its host-feeding on the nymphal instars of the greenhouse whitefly could prove it to be a good candidate for suppressing the greenhouse whitefly populations.