Toxicity of Some Insecticides to the Grasshopper Zonocerus Variegatus (Orthoptera: Pyrgomorphidae)

Abstract

Twenty-one insecticides were tested for acute toxicity by surface film contact method against the grasshopper, Zonocerus variegatus (L.) in the laboratory. Decamethrin, cypermethrin, lindane o,o-diethyl(p-methyl sulfinyl) p’-phosphorothioate, and dieldrin were highly potent. Moderately potent insecticides were propoxur, bioallethrin, telodrin, isodrin, heptachlor and rotenone. A toxic symptom common to all potent insecticides in the female was the opening and closing of ovipositor valves which remained wide open at death. Five insecticides—dieldrin, telodrin, p,p’-DDT, chlorobenzilate, DMC and chlordimeform induced cannibalism among the treated females.

Résumé

Parmi les vingt-et-un insecticides examinés pom la toxicité intense par la méthode contact de la bande de la surface sur la santerelle Zonocerus variegatus (L.) an laboratoire, decamethrin, cypermethrin, lindane, o,o-diethyl (p-methyl sulfinyl) p’-phosphorothioate, et dieldrin étaient fort efficaces. Propoxur, bioallethrin, telodrin, isodrin, heptachlor et rotenone étaient efficaces avec modération. Un symptôme toxique commu a’ tous les insecticides efficases chez la femelle était l’ouverture et al fermeture des tubes de l’oviposteur qui restaient sovent grandes ouvertes à la mort. Cing insecticides, dieldrin, telodrin, p,p’-DDT, chlorobenzilate, DME, et chlordimeform ont prevequé du cannibalisme chez les femelles traitées.