Pear, Pest Control with IGR CME 13406, 1986

Abstract

Abstract Trees in a 25-year-old pear orchard were sprayed by handgun operating at 200 psi. Test plots consisted of 4 single-tree replicates (2 of each variety) arranged in a randomized block. All treatments except the untreated check received a ‘delayed dormant’ spray of Pydrin 2.4EC at 4 oz/100 gal plus 1.5% superior oil and a ‘white bud’ spray of Morestan 2.5WP at 1 lb/100 gal. Three cover sprays of Guthion were timed according to codling moth development (see Washington State University Extension Bull. 1072). Each spray of CME 13406 was applied about 150 to 250 degree-days (base 50°F) earlier than Guthion to coincide with the beginning and peak of egg laying. PP populations were sampled at 2- to 4-week intervals. During May, nymphs were counted on 20 spur leaves/tree (2 leaves/spur). In the 2nd generation and later, terminal leaves were sampled. A top, middle and bottom leaf were collected from each of 6 terminals/tree. Leaves were examined under a stereo microscope. Fruit was evaluated for PP russet and CM damage at harvest. Mite counts were taken by brushing 100 leaves/treatment (25/tree). Leaves were sampled on 3 scaffold limbs from the center to the periphery of the canopy.