In field tests to control the quince treehopper, G. crataegi, DDT was completely effective against both nymphs and adults. The formulation used contained 25% actual DDT plus an inert diluent and suitable wetting agent. Complete knockdown of the adult treehoppers resulted with concs. as low as 2 ounces of actual DDT in 100 gal. The residual effect lasted at least 20 days where the concs. were 12 and 16 ounces per 100 gal., respectively.