Methyl Bromide Efficacy and Residues in Large-Scale Quarantine Tests to Control Codling Moth (Lepidoptera: Tortricidae) on Nectarines in Field Bins and Shipping Containers for Export to Japan

Abstract

Large-scale tests in 1986 through 1992 of the methyl bromide quarantine treatment (48 g per m3 for 2 h at ≤21°C with a 50% volume chamber load) to control codling moth, Cydia pomonella (L.), on nectarines for export to Japan resulted in 100% mortality of 159,829 1-d-old eggs on fruit in field bins and three survivors in 64,004 eggs tested on fruit packed in shipping containers. The true survival proportion at the 95% CL was ≤35 per million based on the total number of eggs in all tests. Methyl bromide sorption in tests with nectarines packed in shipping containers (range, 33.4-41.2%) was lower than in tests with fruit in field bins (range, 49.6-60.5%) because less fruit was placed in the fumigation chamber when packed in shipping containers. The products of mean concentration multiplied by time in all tests were essentially within the recommended values of 68.0 ±3.0 g · h per m3 to provide quarantine security. Forty-eight hours after fumigation, inorganic bromide residues were below the tolerance of 20 ppm. Five days after storage at 2.5°C, mean organic bromide residues were <0.001 ppm. ‘May Glo’, ‘May Diamond’, and ‘Mayfire’ nectarines were approved for export to Japan after fumigation in field bins based on our test results. Efficacy and residue data for fumigation of ‘May Grand’, ‘Firebrite’, ‘Red Diamond’, ‘Royal Giant’, ‘Spring Red’, ‘Summer Grand’, and ‘Fantasia’ nectarines in shipping containers are in review by regulatory agencies.