Trials carried out during 1976 and 1977 have demonstrated the high insecticidal activity of decamethrin againstHeliothis armigera, one of the major pests of the tomato crop in the Cap Vert region of Senegal. Acephate, carbaryl and tetrachlorvinphos also gave acceptable levels of control, whereasBacillus thuringiensis, dichlorvos and dimethoate were unsatisfactory. The effectiveness of all the products was diminished when tomatoes were irrigated by means of overhead rotary sprinklers.