Abstract
Permeability to the postharvest fumigants ethylene dibromide (EDB) and methyl bromide (MB) varied among 10 plastic films tested on grapefruit (EDB) and oranges (MB). Permeability was determined by comparing fumigant residue levels in fumigated film-wrapped citrus fruit and fumigated nonwrapped fruit. Some films restricted passage of the fumigants to the fruit, and residue levels in fruit wrapped with these films were lower than in fumigated, nonwrapped fruit. Residue levels in fruit wrapped with other films were equal to those in fumigated, nonwrapped fruit and these films were judged to be highly permeable to the fumigants. EDB and MB residues were slightly higher in fruit wrapped with three of the films than those in nonwrapped fruit, indicating that these films were slightly less permeable to EDB and MB than to other films tested, and also that desorption of the fumigants from the fruit during post-fumigation aeration was slowed by these three films. The permeability of flexible polymer films to fumigants such as EDB and MB should be a prime consideration when selecting films for wrapping citrus fruit in quarantine situations.