Mortality of Susceptible and Resistant Heliothis virescens Larvae Exposed to Various Petroleum Oils and Insecticide Rates

Spray table tests with cotton Gossypium hirsutum L. leaves demonstrated that petroleum oil/diluent residues caused higher mortality in laboratory susceptible tobacco budworm, Heliothis virescens L., larvae than in a laboratory resistant strain. Paraffinic diluents with bifenthrin caused higher mortality of the susceptible and resistant larvae under conditions of long-term exposure to spray residues than bifenthrin in an isoparaffinic oil or an aromatic solvent. None of the bifenthrin-oil treatments increased mortality above water-bifenthrin in either resistant or susceptible strains.