Mortality Response of Codling Moth to Methyl Bromide Fumigation and Coolstorage

Complete mortality of one-day old codling moth eggs infesting Red Delicious apples was achieved by fumigation with methyl bromide at 24 g/m3 for 2h at 12.0 ± 0.5°C, followed by 18 d coolstorage at mean fruit pulp temperatures in the range 0.52 1.77°C. Non-fumigated coolstored eggs required a period of 33 d exposure at the same temperatures to achieve complete kill. Fumigation followed by coolstorage of small numbers of fifth instar larvae resulted in complete mortality of this life stage after 26 d, the only duration tested. The postharvest disinfestation treatment currently used to export apples to Japan involves fumigation with methyl bromide (as above) followed by a mandatory 25 d coolstorage period at temperatures of 0.5°C and below. Therefore the approved treatment specification used for export apples is very robust in both its coolstorage duration and temperature range.