Susceptibility of Epilachna Dodecastigma Weid. Adults to Some Modern Insecticides.

Eleven insecticides were screened under laboratory conditions against Epilachna dodecastigma Weid. (Coleoptera: Coccinellidae) attacking musk melon. On the basis of LC₅₀ and LC₉₀ values, phosalone, fenthion, quinalphos and phosphamidon were highly toxic (LC₅₀ 0.01 percent and LC₉₀ 0.04 percent) while trichlorfon en-dosulfan and leptophos were least toxic (LC₅₀ 0.02 percent and LC₉₀ 0.09 percent) and chlorpyrifos fenitrothion malathion were modrately toxic (LC₅₀ 0.01 but more than 0.016 and LC₉₀ 0.06 but 0.10 percent). When the persistent toxicities of field weathered residues of promising insecitcides were studied the decreasing order of merit was monocrotophos, phosphamidon, phosalone, fenthion, chlorpyrifos, fenitrothion, quinalphos and malathion.