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Postharvest Pathology and Mycotoxins

Phytotoxic Responses of Citrus Fruit to Fumigation with Ethylene Dibromide. L. G. Houck, Research plant pathologist, Agricultural Research Service, U.S. Department of Agriculture, Protection and Quarantine Research Unit, Horticultural Crops Research Laboratory, Fresno, CA 93727; J. F. Jenner(2), J. S. Tebbets(3), and P. L. Hartsell(4). (2)(3)Biological technicians, Agricultural Research Service, U.S. Department of Agriculture, Protection and Quarantine Research Unit, Horticultural Crops Research Laboratory, Fresno, CA 93727; (4)Physical science technician, Agricultural Research Service, U.S. Department of Agriculture, Protection and Quarantine Research Unit, Horticultural Crops Research Laboratory, Fresno, CA 93727. Phytopathology 75:616-622. Accepted for publication 14 December 1984. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1985. DOI: 10.1094/Phyto-75-616.

Commercially packed California citrus fruit fumigated with ethylene dibromide (EDB) at 24 or 32 g/m³ of storage space for 2 hr at 20 C (30% [v/v] load factor) developed a high incidence of unacceptable rind injury during postfumigation storage (5 C for 3 wk then 20 C for 1 wk). Order of susceptibility to injury by EDB at 32 g/m³ was navel oranges > Valencia oranges > lemons. With EDB at 12 and 16 g/m³ the susceptibility order was Valencias > lemons > navel oranges. Rind injury increased with temperature of fumigation (10<20<30 C). Rind injury decreased (15 > 30 > 58%) with an increase in the load factor (v/v) in the fumigation chamber. Ripe yellow lemons were injured more by EDB fumigation than were less-ripe, silver lemons. More fruit decayed during storage after fumigation at a 15% load factor than at load factors of 30 or 58%. Increasing the EDB dosage from 12 to 32 g/m³ (30% load factor) did not increase fruit decay.