The Toxicology of 4, 6 Dinitro-o-cresol as an Aphid Ovicide12

Abstract

The toxicity of dinitro-o-cresol in aqueous soln., to aphid eggs was studied under controlled conditions against 22 spp. Minimum effective dosages (point of 95% kill) of the toxicant were found to range from 0.003% for the most susceptible spp. to 0.05% for the most resistant. The indicated dosage for eggs of the apple aphid, Aphis pomi, was 0.012%. Spp. whose eggs hatch earliest proved the most susceptible; increasingly more toxicant was required to kill the eggs of later hatching forms. Solns. of dinitro-o-cresol and of its Na, Ca, NH4, and Mg salts were equally effective at the same dinitro-o-cresol concn. Aphid eggs apparently differ little, if any, in susceptibility to dinitro-o-cresol at various stages of their embryonic development.