Sf. Abdelghafar et Co. Knowles, PHARMACOKINETICS OF FENVALERATE IN LABORATORY AND FIELD STRAINS OF HELICOVERPA-ZEA (LEPIDOPTERA, NOCTUIDAE), Journal of economic entomology, 89(3), 1996, pp. 590-593
Pharmacokinetics of fenvalerate-C-14 were examined in the bollworm, He
licoverpa erpa (Boddie), 3rd instars from a pyrethroid-susceptible str
ain (BCIRL-S), a field strain (ARK) that possessed a low level of resi
stance to this pyrethroid (resistance ratio 2.7-fold at LD(90)), and a
composite strain (HZC) that was reared under pyrethroid selection but
did not significantly differ from ARK larvae in its suceptibility to
fenvalerate. We observed differences in rates of fenvalerate penetrati
on and degradation among larvae from the 3 strains. Based on actual di
sappearance of total radiocarbon from the insect rinses, half-times fo
r fenvalerate penetration were approximate to 7, 16, and 18 h in BCIRL
-S, ARK, and HZC 3rd instars, respectively. Fenvalerate was degraded f
astest by HZC larvae followed by BCIRL-C and ARK larvae. The only diff
erence in fenvalerate pharmacokinetics likely related to toxicity was
slower pyrethroid penetration in the ARK and HZC strains as compared w
ith the BCIRL-S strain.