Modification of pesticide toxicants Actara, Desis and Fabcosidine for larvae of Khabra Trogoderma granarium beetle with Prenobyl Piotoxide and phenobarbital

Abstract

This study was designed to evaluate the toxicities of Actara, Decis and Vapcocidin and the effects of the mixed-function oxidase (mfo) enzymes inhibitor, piperonyl butoxide (pb ), and inducer, Phenobarbital (phb ), on the toxicities to the 15 2nd, 3rd, 4th and 51h instar larvae of Trogoderma granarium, using the impregnated filter paper technique. Based on the 24h LC50 values, the three insecticides were highly toxic to the larvae. Decis was about twice as toxic as Actara and both were greatly much more toxic than Vapcocidin. The toxicities of the three insecticides, generally, decreased as the Larval stage advanced (LC50 values in the 5- Larval instars were 1.7, 1.8, 2.2, 2.6, 3.1 0 l/filter paper, respectively, for Decis, 3.0, 3.5, 4.5, 6.0, 7.0 0 1/filter paper, respectively, for Actara and 6.0, 8.0, 11.0, 13.0, 15.0 0 1/filter paper, respectively, for Vapcocidin) and it is considered most likely that the decrease is due to the increase in the mfo enzymes activity. The mfo enzymes modifiers data showed that pband pbb greatly increased and decreased, respectively, the toxicities of the three insecticides. The date also revealed that mfo insecticide detoxifing enzymes activity increased as the Larval stage advanced. The studysuggests that Actara would be an effective alternative to pyrethroids against this insect.