Piperonyl butoxide is a synergist used to enhance the activity of insecticides, including pyrethrin insecticides, through inhibition of cytochrome P450 enzymes (CYPs).1,2 It increases the toxicity of the pyrethroid insecticide deltamethrin to field-collected, deltamethrin-resistant strains of the bed bug C. lectularius by 40- to 176-fold when used at a concentration of 50 μg/μL.2 Piperonyl butoxide also increases the toxicity of the organotin insecticide Plictran to fourth instar larvae of susceptible strains of the cotton leafworm S. littoralis (LD50s = 0.78 and 40 μg/larva with and without piperonyl butoxide, respectively), as well as field strains (LD50s = 0.015 and 1.1 μg/larva with and without piperonyl butoxide, respectively).3 It is not toxic to the freshwater invertebrates H. azteca, C. tentans, and L. variegatus (LC50s = 530, 2,740, and 3,540 μg/L, respectively) and reduces the toxicity of the organophosphate pesticides diazinon , chlorpyrifos , and azinphos-methyl, which require activation by CYP enzymes in these organisms.1 Formulations containing piperonyl butoxide have been used for the control of agricultural, household, and veterinary pests.
1.Ankley, G.T., and Collyard, S.A.Influence of piperonyl butoxide on the toxicity of organophosphate insecticides to three species of freshwater benthic invertebratesComp. Biochem. Physiol.110(2)149-155(1995) 2.Romero, A., Potter, M.F., and Haynes, K.F.Evaluation of piperonyl butoxide as a deltamethrin synergist for pyrethroid-resistant bed bugsJ. Econ. Entomol.102(6)2310-2315(2009) 3.Radwan, H.S.A., Riskallah, M.R., and El-Keie, I.A.Synergistic effects on the toxicity of organotins on cotton leafwormsToxicology14(3)193-198(1979)