The effect of sublethal concentration of three commercial formulations of neem including Kofa, NeemAzal and Nimbecidine on the life table parameters of the greenhouse whitefly, Trialeurodes vaporariorum (Hem., Aleyrodidae)

Greenhouse whitefly, Trialeurodes vaporariorum Westwood is one of the most important pests of vegetables, crops, and ornamental plants. In order to control this pest, it is necessary to find alternative solutions in order to reduce the adverse effects caused by the excessive use of chemical pesticides. Therefore, this research investigated the sub-lethal effect (LC20) of three formulations of Azadirachtin, including Nimbecidine®, NeemAzal T/S®and Kofa® investigated on the greenhouse condition. Experiments were carried out in the greenhouse with light conditions of 16:8 hours (light: dark), temperature 27±2 °C, and 65±5% RH. The results showed that Nimbecidine®formulation with LC50 was equal to 0.261a.i. mg/L was the most toxic formulation on the third instar nymph of this pest. In investigating the sub-lethal effects of all three formulations, they affected the duration of immature stages, survival, longevity, and fecundity of the whitefly. The lowest net rate of reproduction (R0) (3.68 offspring), the intrinsic rate of population increase (r) (0.06 1/day), and the finite rate of population increase (λ) (1.06 1/day) were related to the Nimbecidine® formula. However, the average duration of one generation (T) was not affected by the sublethal concentration of the three formulations. The findings of the present research indicated the adverse effects of the sub-lethal concentration (LC20) of all three neem formulations on the biological parameters and population growth of this pest. Accordingly, it is possible to use the sublethal concentration of the Nimbecidine® formula in the integrated management of this pest