Management of European Red Mite (Acari: Tetranychidae) and Several Aphid Species on Apple with Petroleum Oils and an Insecticidal Soap

Abstract

Three petroleum oils and one insecticidal soap were evaluated in laboratory tests at different rates for ovicidal efficacy against overwintering Panonychus ulmi (Koch) eggs. Sunspray 6E and Volck Supreme oils caused the greatest mortality of all materials tested. Sunspray 6E+ caused less mortality than did the Sunspray 6E and Volek Supreme but greater mortality than Safer Insecticidal Soap Concentrate, which caused only slightly greater mortality than the distilled water check. Field applications of the same materials by airblast sprayer and high-pressure handgun caused less mortality of overwintering eggs than in the laboratory study. Summer applications of these materials were tested for their ability to suppress mite and aphid populations throughout the growing season. Applications of all materials provided significant control of populations of P. ulmi , rosy apple aphid, Dysaphis plantaginea (Passerini), and a green aphid complex made up of the apple aphid, Aphis porni De Geer, and the spirea aphid, Aphis spiraecola Patch. Spray volume, coverage, and rate of material applied were related to mite and insect control and plant phytotoxicity; the greater the volume, coverage, and rates used, the greater the control and phytotoxicity obtained. Volck Supreme oil, particularly at the high rate, caused more damage to fruit and foliage than did any of the other treatments. Suns pray 6E and Suns pray 6E+ appear to be equally safe to fruit and foliage based on phytotoxicity ratings taken throughout the growing season.