Description Malathion 5 insecticide is used to control insects in the field, including aphids, spider mites, armyworms, grasshoppers, Japanese beetles, leafhoppers, flies, mosquitos and a variety of other insects. Malathion 5 may be applied by ground or air and is labeled for ULV applications in many crops. To lock in deposition or spray coverage and lock out drift, include InterLock or MasterLock adjuvants.