Penetration, excretion and metabolism of 14C malathion in susceptible and resistant strains of Plutella xylostella.
1. The rate of penetration 14C malathion into the larvae of the diamondback moth, Plutella xylostella L., was found to be significantly different in an R-strain and S-strain. The rate of penetration was more rapid in the R-strain during the first hour after treatment. 2. The rate of metabolism in vivo and the rate of excretion were also higher in the R-strain compared with the S-strain. 3. The main metabolites produced in both strains were malathion dicarboxylic acid and desmethyl malathion. 4. The mechanism of insecticide resistance in Plutella xylostella L. is multifactorial, and involves a higher rate of penetration into the larvae of the R-strain, a higher activity of enzymes involved in its metabolism, and a higher level of excretion of the toxic compounds from the body of the R-strain compared with the S-strain.
School of Biological Sciences, University of Birmingham, U.K.
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Doichuanngam
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RA
Thornhill
D000818:Animals; D002250:Carbon Radioisotopes; D005243:Feces / Q000737:chemistry; D006358:Hot Temperature; D007305:Insecticide Resistance / Q000235:genetics; D007814:Larva / Q000378:metabolism; D008294:Malathion / Q000378:metabolism / Q000493:pharmacokinetics* / Q000652:urine; D009036:Moths / Q000378:metabolism*; D013045:Species Specificity; D014835:Volatilization
D002250:Carbon Radioisotopes; D008294:Malathion