Toxicity of pyrethroids and other insecticides against susceptible and resistant tobacco budworm larvae and synergism by chlordimeform.

1987

Tobacco budworm resistance to pyrethroids: resistance spectra, synergists, and substitute insecticides.

1988

Efficacy and economic returns from various insecticide combinations applied for tobacco budworm control in the Brazos River Valley.

A field efficacy evaluation revealed significant differences in efficacy among a few of the numerous insecticides or combinations of insecticides applied for Heliothis spp. control. An increasing proportion of made up this field population during the test period. Partial budgeting revealed that the net returns from applying any treatment were directly proportional to the resulting yield obtained from that treatment.

Synergism of pyrethroids by chlordimeform against susceptible and resistant Heliothis.

Chlormideform sunergizes synthetic pyrethoids against both Heliothis zea and H. virescens. Synergism is grater against the latter species. The precise mechanism of the synergism is not known but probaly involves target site effects rather than inhibition of metabolism. In preliminary test with pyrethroid resistant insects from western Texas evidence was obtained that chlordimeform was more synergistic with a strain than with laboratory insects.