Codling Moth Control in Pears, 1996

Abstract

Abstract The study was conducted on mature ‘Bartlett’ pear trees in a commercial orchard near Fairfield, Calif. Eighteen treatments were replicated 4 times in a RCB design. Each replicate consisted of an individual tree. Treatments were applied with a hand-held 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 31 Mar biofix for the first generation and 17 Jun for the second generation using a single sine horizontal cutoff model with a lower threshold of 50°F and upper threshold of 88°F. Air temperatures were taken from the IMPACT weather station in Cordelia. Target degree-day timings and “actual timing-date” in parentheses were: V-71639 and CGA-59205 at 100 (104-10 Apr) and 500 DD (523-14 May) from 1st biofix; CM-001 at 200 (216-25 Apr) and 600 DD (699-28 May) from 1st biofix and 200 DD (280-1 Jul) from 2nd biofix; CM002/X, Brigade and Azinphos-M (grower standard) at 250 (288-29 Apr) and 650 DD (699-28 May) from 1st biofix and 250 DD (280-1 Jul) from 2nd biofix. Due to rain on 15 through 18 May and again on 21 May and high winds through 25 May, the 600 DD and 650 DD applications were postponed until 28 May (699 DD). In addition, V-71639 and CGA-59205, which were applied on 14 May, were retreated on 28 May. Control of the first CM generation was evaluated on 6 Jun by inspecting 50 fruit from the bottom of the tree canopy and 50 fruit from the top of the three canopy per replicate. Control of the second CM generation was evaluated at commercial harvest on 22 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 TSM, ERM and PP nymphs was evaluated weekly from 18 Jun through 16 Jul by sampling 10 exterior and 10 interior leaves/replicate. The leaves were brushed and the motile TSM, ERM and PP nymphs were counted under magnification (20X).