The Action of the Systemic Insecticide Systox, on Pieris brassicae (L.) and Phaedon cochleariae (F.)

Abstract

The mixture of O, O-diethyl O-ethlmercaptoethyl thiophosphate and O, O-diethyl S-ethylmercaptoethyl thiophosphate, known as Systox, which has been previously tested against Aphids, has now been tested as a systemic insecticide against the eggs and larvae of Pieris brassicae (L.) and the eggs, larvae and adults of Phaedon cochleariae (F.).Systox is toxic by direct contact to all stages of these insects but is much less effective in this way than diethyl p-nitrophenyl phosphate (paraoxon).As a systemic insecticide applied to the roots of teh host-plant, Systox again acts on all stages of the insects (except the eggs of Phaedom), but, compared with the dose which killed Aphids, about twice as much is required to kill Phaedon larvae and between 20 and 100 times as much to kill Pieris larvae, depending on the method employed.When applied systemically Systox, like paraoxon, can prevent the emergence of Pieris larvae from the eggs.