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Abstract
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The Greenhouse whitefly Trialeurodes vaporariorum (Westwood), (Hem.: Aleyrodidae) is a key pest in rose greenhouses in the world. For control this pest, bioassay of Neem essential oil, Citowett and Volk on fixed stages (second, third and puparium) and adult stage of the insect were performed under greenhouse conditions. In additional, the bioassay of deltamethrin on adult and buprofezin on the nymphs and synergistic rate (SR) of three oils on deltamethrin and buprofezin were assessed. The bioassay was carried out in clear plastic cages containing a leaf with three leaflets connected to the plant, containing 30 nymphs or 30 adults. 350 rose cuttings (Rosa hybrida Apollo) were prepared and planted in pots with a diameter of 18cm. The whiteflies were collected from the infested rose plants; their species were determined and then reared on the roses. Each pot plant was infested with a five leaflets leaf that consist ap proximately 200 nymphs. In each pot a three-leaflet leaf was separated in a cage. The number of insects (adults and nymphs) in each cage was 30 for each pot, and 150 for each treatment. The range of concentrations for bioassay was determined based on Robertson and Preisler method and were estimated with logarithmic distance for the mortality of 25 to 75 percent for 5 concenterations. The leaves were immersed in the solution for 5 seconds and after one hour, 30 one-day old adults released to a plastic cage including a three-leaflet leaf connected to the plant. One day after treatments, the adult insects were separated and dead adults were counted. But one week after treatments the leaves were separated from plant with cages and dead nymphs were counted with a stereomicroscope (10X). The results showed LC50 of deltamethrin mix to oils (Neem, Citowett and Volk) for adults as 417.55, 290.51 and 639.07 ppm, respectively. Also SR effect of Neem oil, Citowett and Volk on deltamethrin for adult mortality were estimated as 3.62, 5.45 and 2.56, respectively. Buprof
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