For the development of more effective insecticides for aphids, including the cotton aphid, Aphis gossypii Glover, control released insecticides were developed and tested as new type of formulation for the cotton aphid. Etofenprox is a target-of-control-released formulation that is toxic to insects with piercing-sucking type mouths including aphids and hoppers. The insecticidal effect of etofenprox is distinguished among others; however, continuance period of the effect of insecticide is shorter than other insecticides. In addition, the control effect of control released etofenprox on the cotton aphid was examined. The results show that control released etofenprox induced no control effects to the cotton aphid within 5 days of treatment. The cotton aphid's population was increased, and their reproduction rate was also high. However, control effect was shown to have very low levels 7 days after treatment, and it increased to higher effect. It is supposed that it is possible to control the cotton aphid using the type of control released etofenprox with a kitosan carrier. It is necessary to develop a more effective carrier type to release more of the insecticidal ingredient on the leaf after spraying.