The Control of the Pear Leaf Blister Mite with Endosulfan

Abstract

Single applications of endosulfan at dosages of 0.25 and 0.5 lb. of active ingredient per 100 gal. of spray were evaluated for the control of the pear leaf blister mite, Eriophyes pyri (Pagenstecher), on young pear trees. Phostex® (a mixture of his (dialkyloxyphosphinothioyl) disulfides (alkyl ratio 75% ethyl, 25% isopropyl)) lime sulfur with oil, and binapacryl were also included in the trials. The treatments were applied at various times after harvest until the delayed dormant period. Based on blistered fruit and leaf cluster counts, endosulfan as well as lime sulfur with oil provided extremely effective control, irrespective of the time of application. The effectiveness of Phostex and hinapacryl was limited to that period in which the fall migration of the mites from the leaf blisters has been completed. Applications of lime sulfur and oil made in September and October caused severe leaf burn and subsequent defoliation. None of the other materials included in the trials and any apparent form of phytotoxicity.