Methyl Bromide Quarantine Treacment for Codling Moth (Lepidoptera: Tortricidae) in Unshelled Yalnuts

Unshelled walnuts were artificially infested with diapausing fifth ins tar codling moth, Cvdia nomonella (L.), larvae and fumigated with 56 g/m3 methyl bromide for 4 h at 15.6°C under a reduced pressure of 100 mm Hg. When 34,959 were treated, one larva survived, indicating a survival rate of 2.91 larvae per 100~000 treated. The upper 95% CL for this survival rate was 13.8 larvae per 100,000 treated. When larval survival rates of methyl bromide fumigation tests of a normally applied domestic treatment were combined with survival rates from quarantine vacuum fumigation tests, the 95% CL survival rates were ~0.4 larva per 100,000 treated. cultivars tested, nor from variation in the size of No significant the four walnut the walnuts of differences were found in mortality of larvae among each cu1tivar. Whole.walnuts sorbed-79.6% of the methyl bromide applied, therefore a relatively high dosage of methyl bromide was required to obtain an efficacious treatment. The treatment was accepted by the Japanese Ministry of Agriculture, Forestry and Fisheries in 1986: KEY ~ORDS: Insecta, Cvdia nomonella, methyl bromide fumigation, unshelled walnuts