Insecticide Cross-Resistance in Pyrethroid-Resistant Strains of Tobacco Budworn (Lepidoptera: Noctuidae)

Dose-mortality regressions were estimated for eight pyrethyroids applied to fenvalerate-resistant strain of tobacco bud worm, Helios this viruses (F.), collected during 1986. A broad spectrum of cross-resistance was detected to permethrin (16.0-fold), cypermethrin 9.4-fold), flu validate (15.5-fold), biphenthrin (11.9-fold), esfenvalerate (10.4-fold), and deltamethrin (6.7-fold), although only cypermethrin, fenvalerate, and permethrin have been used extensively in the field. Cross-resistance to lambda-cyhalothrin was consistently low (1-2-fold) on several strains of tobacco bud worm. Pyrethroid-resistant strains tested with methyl parathion and profenofos exhibited 2.0-15.8-fold and 4.1-5.1-fold levels of resistance, respectively. Methyl parathion resistance was correlated with increasing levels of fenvalerate resistance.