Each year, I hear the statement that grasshoppers must be sprayed when they are small because adult grasshoppers are notoriously hard to kill. I was not certain that this statement was true, so last year I sprayed adult differential grasshoppers in a laboratory experiment. Ten adult grasshoppers were singly caged in paper cups and covered with nylon mesh for each treatment. Cups containing the grasshoppers were then sprayed in a mechanical spray chamber with an insecticide at a rate of 19.6 gallons of water per acre and 25 psi by using an 80005-E nozzle.