Petroleum oils in orchard mite control

Investigations with oil sprays for the control of European red mite, <i>Panonychus ulmi</i> (Koch), revealed the following: as dormant sprays, Pennsalt Superior oil was more effective than Shell Neutrol; when either oil was applied at the half-inch green bud stage, the control was better than with dormant applications of the same oil; half-inch green bud sprays of Pennsalt Superior and Imperial 862 were equal in effectiveness. There was no difference in control with a half-inch green bud spray of Volek Supreme, Orchex 796, or Shell Neutrol; summer sprays of Pennsalt Superior oil gave effective control of European red mite. None of the above applications of oil gave effective control of the McDaniel spider mite, <i>Tetranychus mcdanieli</i> McG. Half-inch green bud sprays of Pennsalt Superior, Imperial 862, Orchex 796 and, to a lesser extent, Volek Supreme caused bark lenticel injury to Delicious apple trees but not to Mclntosh, Newtown, Rome Beauty, Jonathan, Winesap and Stayman apple trees. Shell Neutrol oil did not produce bark injury