California nectarines [Prunus persica (L.) Batsch. var. nectarina (Ait) Maxim.] packed in single-layer corrugated fiberboard boxes were fumigated with methyl bromide (MB) at a rate of 48 g·m-3 for 21 hours at 21C and normal atmospheric pressure and a 50% load (v/v) as a quarantine treatment for codling moth (Cydia pomonella L.). When the boxes were loosely stacked with spaces between them or tightly stacked and forced-air fumigated, concentration multiplied by time (C × T) relationships were > 68 g·m-3·h-1, which is recommended for efficacy. Tightly stacked boxes that were not forced-air fumigated had C × T products <68 g·m-3·h-1. Organic bromide residues were <0.001 μg·g-1 and inorganic bromide residues were < 7.0 μg·g-1 after 3 days. A trace to slightly phytotoxic response was observed in `Summer Grand' and `Fantasia' nectarines in 1989 but not in 1990.
R.T. Hinsch, C.M. Harris, P.L. Hartsell and J.C. Tebbets
P.L. Hartsell, C.M. Harris, P.V. Vail, J.C. Tebbets, J.M. Harvey, V.Y. Yokoyama and R.T. Hinsch
Residues and the toxic effects of methyl bromide (MB) were determined in fumigation tests with six cultivars of nectarine [Prunus persica (L.) Batsch. var. nectarina (Ah.) Maxim.]. `Fantasia', `Firebrite', and `Summer Grand' were treated in wooden field bins in a commercial facility, whereas `May Fire', `May Glo', and `May Diamond' were fumigated in smaller fiberglass chambers. The treatment of 48 g MB/m3 for 2 hours at 21C and normal atmospheric pressure with a load factor of 50% (179 kg·m-3) was that proposed for quarantine eradication of the codling moth (Cydia pomonella L.). The appearance of the fruit, as well as the soluble solids content, were not affected by the MB fumigation; however, ripening of `May Grand' and `Firebrite' was delayed slightly. Sorption of MB was 55%. Desorption rates of organic bromide were not significantly different among the six treated cultivars; all fruits contained <0.001 μg·g-1 after 7 days of storage at 2.5C. Inorganic bromide residues in all treated fruits were <8.0 μg·g-1.