LD 50  values of methyl parathion and endrin to tobacco budworms and bollworms collected in the Americas and hypothesis on the spread of resistance in these lepidopterans to these insecticides.
D000818:Animals; D002489:Central America; D001517:Coleoptera / Q000187:drug effects*; D004732:Endrin; D007300:Insect Control; D007313:Insecta / Q000187:drug effects*; D007305:Insecticide Resistance; D007306:Insecticides / Q000633:toxicity*; D007928:Lethal Dose 50; D008800:Mexico; D010278:Parathion / Q000633:toxicity*; D013020:South America; D014481:United States
D007306:Insecticides; D010278:Parathion; D004732:Endrin