Pear, Seasonal Pear Psylla Control Experiment, 1994

Experimental sprays were applied to replicated three tree plots in a block of ‘Bartlett’ (84%), ‘Bosc’ (9%), and ‘D’Anjou’ (7%) pears. Trees were planted to a spacing of 24 × 24 ft and were 15 years old. Each treatment was replicated four times in a RCB design. Experimental sprays were applied with a Friend Airmaster ‘309’ calibrated to deliver 100 gpa at 2.2 mph. All plots received a regular fungicide maintenance schedule of Benlate 50DF, Streptomycin and Ziran 76WP. All sampling was conducted on the middle ‘Bartlett’ tree in each replicate. All treatments were evaluated by counting eggs and/or nymphs from leaf samples using a binocular microscope under 10X magnification at 5-14 d intervals. Counts were made on 15 spur-leaf samples from 6 May to 18 May; on 5 spur and 10 third most distal leaf samples from 24 May to 30 Jun; and on 15 third most distal leaf samples on 7 Jul to 28 Jul. Adult PP were sampled by making two taps on eight limbs per center plot tree. All adults dropping onto 0.2 m2 collecting tray were counted. Pear fruits (25 per replicate) were rated as 0 (no russet), 1 (1-10% russeted surface), 2 (11-25% russeted surface), 3 (26-50% russeted surface), or 4 (>51% russeted surface). Possible ranges are 0-30 (none to 1-10% russeted surface), 31-60 (1-10% to 11-25% russeted surface), 61-90 (11-25% to 26-50% russeted surface), and 91-120 (26-50% to >51% russeted surface).