Consumption rates and predatory activity of adult and fourth instar larvae of the seven spot ladybird, Coccinella septempunctata (L.), following contact with dimethoate residue and contaminated prey in laboratory arenas

The sub-lethal effects of dimethoate residues on the condition and predatory efficiency of adult and fourth instar larvae of Coccinella septempunctata were investigated in laboratory arenas. Overall, predatory efficiency of both adult and larval C. septempunctata was significantly reduced following encounter with dimethoate residues and treated prey. Prey-choice experiments revealed that adult coccinellids consumed significantly fewer treated than untreated aphids over the 5-h experimental period. Fourth instar larvae preferentially consumed untreated aphids when given the choice of full rate dimethoate treated aphids or untreated aphids. The implications for post-treatment coccinellid survival and integrated pest management are considered.