Toxicity of selected biorational insecticides to Pulvinaria aurantii Cockerell and its predator, Cryptolaemus montrouzieri Mulsant in citrus field
ABSTRACTThe citrus cottony scale, Pulvinaria aurantii Cockerell, is the most important pest of citrus orchards in northern Iran in recent years. Owing to the harmful impacts of chemical insecticides, the use of biorational pesticides seems a safe and convenient way to control this pest. The present investigation was set up to study contact toxicity of various biorational and chemical compounds on the first, second instar nymph and overwintering adult of the citrus cottony scale, P. aurantii, and its predator, Cryptolaemus montrouzieri Mulsant under field conditions. The results indicated that the highest percentage of mortality of first instar nymph of the citrus cottony scale was observed in the Dayabon treatment of 9 and 10 ml/L, 100.0% ± 0.0% and the lowest percentage was observed in Palizin treatment of 1.5 ml/L, 34.7% ± 2.9%. In the second instar nymph, the highest mortality was seen in the Dursban treatment of 2 ml/L, 94.7% ± 2.4% and the lowest mortality in the Palizin treatment of 1.5 ml/L, 30.0% ...