Gw. Elzen et al., INHERITANCE, STABILITY, AND REVERSION OF INSECTICIDE RESISTANCE IN TOBACCO BUDWORM (LEPIDOPTERA, NOCTUIDAE) FIELD POPULATIONS, Journal of economic entomology, 87(3), 1994, pp. 551-558
Responses of an insecticide-resistant strain of tobacco budworm, Helio
this virescens (F.), were examined in the laboratory by using three di
fferent insecticide bioassays during continuous culture without insect
icide selection pressure. Resistance to the pyrethroid cypermethrin an
d the carbamate thiodicarb did not revert to susceptiblity until 12 ge
nerations in culture- Previous studies indicated that reversion tends
to occur much more rapidly in this species. The temporal sequence of r
esistance in field populations of H. virescens collected in 1990 and 1
991 was determined by using a spray-chamber bioassay. Resistance to se
veral classes of insecticides varied and was often high before and dur
ing the cotton growing season. Inheritance of resistance to insecticic
les in H. virescens was examined with two different bioassays. Results
of bioassays with third instars and adults were similar. Resistance i
n reciprocal crosses was intermediate to that of the parent susceptibI
e and resistant strains. Codominant mechanisms of resistance to the py
rethroid and carbamate insecticides are suggested from the data.