Fourteen insecticides were tested by direct contact against second-instar nymphs of a grasshopper, Melanoplus sanguinipes F. Of these, seven were judged to be sufficiently promising to be compared for toxicity and persistence as deposits on wheat seedlings. Comparison with a dieldrin standard showed that Dursban, Dibrom, and malathion were extremely effective by contact but had little persistence on growing wheat. Baygon was extremely effective by contact and showed some persistence. CIBA 9643 and dimethoate were the only two compounds to show persistent effects almost equivalent to dieldrin, and CIBA 9643 was more toxic than dieldrin by direct contact.It was concluded that CIBA 9643 was the only compound, of those tested, which might give grasshopper control equivalent to, or better than, dieldrin or the currently recommended dimethoate.