Abstract
The citrus cottony scale, Pulvinaria aurantii Cock. (Hem.: Coccidae) is one of the most important citrus pests in Iran. This study investigated the toxicity and synergistic effects of organophosphorous insecticides (Malathion, Chlorpyrifos, Buprofezin and DG oil) on first nymphal instars of P. aurantii in the laboratory conditions (25 ± 1 °C, 75 ± 5% RH and 16L:8D photoperiod). The values of LC50 for Malathion, Chlorpyrifos and Buprofezin insecticides on the first nymphal instars were calculated as 76.90, 105.25 and 24.70 ppm, respectively. Also, results indicated that Buprofezin and Pyriproxifen are the most effective insecticides on first nymphal instars of P. aurantii. The values of LC50 for each insecticide without oil and in half dose along with DG oil were equal. This was an indication for synergism role of DG oil combination. The results of this study showed that DG oil not only decreases the consumption of insecticides, but also increases their efficacy.
Acknowledgement
This work was supported by Faculty of Agricultural Sciences, Shahed University, Tehran, Iran.