Codling Moth Control with Insect Growth Regulators, 1995

Abstract

Abstract The trial was conducted in a commercial walnut orchard near Tracy, Calif. Twelve treatments were replicated four times in a RCB design. Each replicate consisted of an individual tree. Treatments were applied with a hand-held orchard sprayer operating at 300 psi and delivering 400 gpa of finished spray (5.7 gal/tree). Application timings were based on degree days (DD). DD were calculated with a 2 Apr biofix for the first generation and 25 Jun biofix 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 from the San Joaquin County weather station in Tracy. Target application timings were: Confirm and Neemix-250 DD from 1st and 2nd biofix and 1250 DD from 2nd biofix, Dimilin-300 DD (combined with Lorsban), 900 and 1900 DD from 1st biofix, Comply and Pyriproxyfen-300 DD (combined with Lorsban or Lorsban alone) from 1st biofix, 100 and 1100 DD from 2nd biofix and grower standard-300 DD from 1st biofix, 250 and 1250 DD from 2nd biofix. Control of the overwintering CM generation (first application) was evaluated by inspecting all dropped nuts weekly from 31 May through 7 Jul for CM infestation. In addition, control of the overwintering generation was evaluated by banding each tree with single sided corrugated cardboard on 15 May. The cardboard was removed and inspected for CM larvae or pupae on 7 Jul. Control of the summer generations was evaluated by inspecting 100 nuts/tree at commercial harvest on 18 Sep for CM and NOW infestation.