Five experiments were conducted in May and June 1963, using insecticides applied by aircraft against both adults and larvae of the cereal leaf beetle, Oulema melanopa (L.), in Mlichigan and Indiana. Both toxicant and spray volume were tested on oats and wheat. Compounds studied included malathion, carbaryl, Bayer 39007 (o-isopropoxyphenyl methylcarbamate), Guthion® (O, O-dimethyl S- (4-oxo- 1,2,3-benzotriazin-3(4H)-ylmethyl) phosphorodithioate), and dimethoate. Materials were evaluated both from field observation and assay of plants brought from the field to the laboratory. The data show that 1 lb of active carbaryl was more effective than the same amount of malathion because of its persistent residual activity, its apparent ovicidal action, and equally high effectiveness when applied from an altitude of 50 ft. Carbaryl was more effective when combined with a sticker. The volume of spray applied, ranging from ½ gal to 5 gal per acre, did not appear to be significant. Guthion was highly effective against larvae of the cereal leaf beetle. Bayer 39007, owing to formulation problems, cannot be judged by its performance in these studies. Dimethoate did not give satisfactory control.