Toxicity and Neurophysiological Effects of Fipronil and Its Oxidative Sulfone Metabolite on European Corn Borer Larvae (Lepidoptera: Crambidae)
- 1 October 2001
- journal article
- Published by Elsevier BV in Pesticide Biochemistry and Physiology
- Vol. 71 (2), 97-106
- https://doi.org/10.1006/pest.2001.2564
Abstract
The phenylpyrazole insecticide fipronil is the first compound of its class to be registered for commercial use. The mode of action of this class of insecticides involves antagonism of the inhibitory neurotransmitter, γ-aminobutyric acid (GABA). The sulfone metabolite of fipronil has been reported to be similar in toxicity to the parent compound. In this study, the toxicity and neurophysiological effects of fipronil and the sulfone metabolite were determined for European corn borer larvae. Fipronil was very toxic to neonate European corn borer larvae in feeding bioassays (LC50 = 3.34 ng a.i./cm2 of treated diet) and to fifth instars in topical bioassays (LD50 = 18.78 ng/insect). The sulfone metabolite was slightly more toxic to neonate larvae (LC50 = 1.44 ng a.i./cm2) and equally toxic to fifth instar larvae (LD50 = 19.54 ng/insect) compared with the parent compound. Neonate larvae preexposed to piperonyl butoxide (PBO) residues coated on the inside of glass scintillation vials for 6 h at 100 μg/vial resulted in significant antagonism of fipronil toxicity (LC50 = 4.39 ng a.i./cm2), whereas preexposure to PBO at 1 μg/vial had no effect (LC50 = 2.91 ng a.i./cm2). Fifth instars topically treated with 10 μg of PBO caused significant antagonism of fipronil toxicity (LD50 = 34.41 ng/insect). Electrophysiological recordings of spontaneous electrical activity were conducted on isolated ventral nerve cords from fifth instar larvae. Results from these experiments indicate that fipronil and its sulfone metabolite both reverse the inhibitory effect of GABA on spontaneous electrical activity. Fipronil, however, caused an increase in spontaneous electrical activity relative to that of the sulfone metabolite.Keywords
This publication has 17 references indexed in Scilit:
- Fipronil: An Ultra-Low-Dose Bait Toxicant for Control of Red Imported Fire Ants (Hymenoptera: Formicidae)The Florida Entomologist, 1998
- Fipronil seed treatments for the control of chironomid larvae (Diptera: Chironomidae) in aerially-sown rice cropsField Crops Research, 1998
- Field trials of fipronil for control of Rhammatocerus schistocercoides (Rehn, 1906) hopper bands in BrazilCrop Protection, 1998
- Antagonism of Fipronil Toxicity by Piperonyl Butoxide and S, S, S-Tributyl Phosphorotrithioate in the German Cockroach (Dictyoptera: Blattellidae)Journal of Economic Entomology, 1997
- Toxicity of Fipronil to Susceptible and Resistant Strains of German Cockroaches (Dictyoptera: Blattellidae) and House Flies (Diptera: Muscidae)Journal of Economic Entomology, 1997
- Toxicity of fipronil to German and American cockroachesEntomologia Experimentalis et Applicata, 1997
- Actions of the insecticide fipronil, on dieldrin‐sensitive and ‐resistant GABA receptors of Drosophila melanogasterBritish Journal of Pharmacology, 1995
- Actions of agonists and convulsant antagonists on a Drosophila melanogaster GABA receptor (Rdl) homo-oligomer expressed in Xenopus oocytesNeuroscience Letters, 1994
- Cyclodiene resistance at the insect GABA receptor/chloride channel complex confers broad cross resistance to convulsants and experimental phenylpyrazole insecticidesArchives of Insect Biochemistry and Physiology, 1994
- Action of Phenylpyrazole Insecticides at the GABA-Gated Chloride ChannelPesticide Biochemistry and Physiology, 1993