Tests conducted with undiluted technical malathion applied by aircraft against rangeland grasshoppers in 1963 at rates as low as 6 fluid oz/acre, and the cereal leaf beetle, Oulema melanopa (L.), in 1964 at 5 fluid oz/acre demonstrated the effectiveness of this material in controlling these insects. On the basis of these favorable results, undiluted technical malathion applied by aircraft at rates as low as 9 fluid oz/acre was tested against the boll weevil, Anthonomus grandis Boheman, in June 1964 near Harlingen, Texas. Eight oz of methyl parathion and 4 oz of Guthion® (O,O-dimethyl S-(4-oxo-1,2,3-benzotriazin-3(4H)- ylmethyl)phosphorodithioate) each applied in 3 gal water/acre served as standards. Results revealed that all rates of technical malathion used without dilution were apparently at least equal in performance to the standards. Further tests are planned to verify these findings.