Inhibitory effects of pyriproxyfen on some physiological parameters of Adalia decempunctata L. (Col.: Coccinellidae)

The lady beetle Adalia decempunctata L. (Col.: Coccinellidae) is known as the ten-spotted ladybeetle, whose larvae and adults are active hunters. These insects have been reported from several stone-fruit trees, seed-fruit trees, broad leaved forest trees and coniferous forest trees infested with pests like aphids, mealybugs and psyllid from several countries on the world. The culture of this predator was maintained in laboratory condition (25 ± 2 ºC, 75 ± 5% RH and 16:8h L:D). In this research, the bioassays of pyriproxyfen was performed through topical application method. The concentration of IC10, IC30, IC50 and IC90 were estimated 18.6, 33.1, 49.3 and 130.6 µg/ml, respectively. Also, in order to have a better understanding, some of the most important biochemical parameters were evaluated in the 4th instar larvae treated with sublethal concentrations of pyriproxyfen. The results showed that lipid and protein amount were relatively increased compared to control, while the glycogen amount was reduced in treated larvae. The activity of detoxifying enzymes (Glutathione S-transferase and general esterases) in treated larvae were significantly increased compared to control. The activity of peroxidase was also increase significantly compared to controls. As the pyriproxyfen is a juvenile hormone analogue, therefore the growing stages of this predator is affected. While adults that have surpassed this stage are no longer dependent to growth hormones and are less affected. Hence, supplementary evaluation of the use of pyriproxyfen and this predator at the same time under field conditions is needed.