Codling Moth Control in Pears, 1997

Abstract

Abstract The study was conducted on mature ‘Bartletty’ pear trees in a commercial orchard near Fairfield, CA. Eight treatments were replicated four times in a RCB design. Each replicate consisted of an individual tree. Treatments were applied with a handheld orchard sprayer operating at 200 psi and delivering 200 gpa of finished spray (2.87 gal/tree). Application timings were based on degree days (DD). DD were calculated with a 25 Mar biofix for the first generation and 1 Jun for the second generation using a single sine horizontal cutoff model with a: lower threshold of 50°F and an upper threshold of 88°F and with air temperature data from the IMPACT weather station in Cordelia. Target DD application timings (with actual DD timings and dates in parentheses) were: Knack and Comply with or without Volck oil at 100 DD (137 DD-8 Apr) followed by Azinphos-M at 650 DD (678 DD-16 May) from 1st biofix and 250 DD (311 DD-17 Jun) from 2nd biofix; Comply with Volck oil at 100 DD (137 DD-8 Apr) and 500 DD (521 DD-8 May) from 1st biofix followed by Azinphos-M at 250 DD (311 DD-17 Jun) from 2nd biofix; Danitol, Brigade, and Azinphos-M (industry standard) at 250 (294 DD-21 Apr) and 650 DD (678 DD-16 May) from 1st biofix and 250 DD (311 DD-17 Jun) from 2nd biofix. Control of the first CM generation was evaluated on 4 Jun by inspecting 50 fruit from the bottom of the tree canopy and 50 fruit from the top of the tree canopy/replicate. Control of the second CM generation was evaluated at commercial harvest on 21 Jul by inspecting a maximum of 125 fruit from the bottom of the tree canopy and 125 fruit from the top of the tree canopy per replicate. Control of motile TSSM, ERM, and PP nymphs was evaluated weekly from 4 Jun through 21 Jul by sampling 10 exterior and 10 interior leaves/replicate. The leaves were brushed and the motile TSSM, ERM, and PP nymphs were counted under magnification (20X).