|Tebbets, John - Steve|
Submitted to: Crop Protection Journal
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/2/2014
Publication Date: 9/1/2014
Citation: Leesch, J.G., Smilanick, J.L., Muhareb, J., Tebbets, J.S., Hurley, J.M., Jones, T.M. 2014. Effects of box liner perforation area on methyl bromide diffusion into table grape packages during fumigation. Crop Protection Journal. 63:36-40. Interpretive Summary: Table grapes are picked, placed in boxes, and refrigerated before their distribution to markets occurs; when placed in boxes, plastic liners are used inside boxes of table grapes to retard moisture loss from the grapes to retain their quality to better appeal to consumers. However, to prevent the introduction of exotic insect pests, the liners within boxes of table grapes imported from foreign countries must be perforated to allow the diffusion of the fumigant methyl bromide gas into the packages to control them. We evaluated gas diffusion into packaged grapes with a range of common liners and found methyl bromide diffusion was adequate and little influenced by the size of the perforations, indicating the treatment commonly used is an effective action to reduce the risk of the introduction of potentially damaging exotic insect pests into the USA.
Technical Abstract: Plastic liners are used inside boxes of table grapes to retard moisture loss from the grapes and to contain sulfur dioxide gas released inside the packages to control postharvest decay. However, to control organisms of quarantine concern, regulators specify exported packages must be fumigated with methyl bromide (MB), and to enable adequate diffusion of the fumigant into the packages they specify the liners must be perforated. The percentage of the area of the liner that is perforated, formerly stipulated to be not less than 0.3%, was recently increased to not less than 0.9%. Two MB fumigation schedules specified for control of the Chilean mite, Brevipalpus chilensis, were applied to grape packages with high-density polyethylene liners with perforated areas of 0.9% or with SO2-releasing liners with perforated areas of 0.3, 0.6, or 0.9%. Package and chamber concentrations were measured repeatedly for up to three hours during MB fumigation at 4.4 or 6.0 ºC with a dosage 64 mg L-1 or at 26.7 ºC with a dosage 56 mg-L-1. Diffusion was similar and rapid into the packages among all perforated areas. MB concentrations inside the packages were not less than 95% of those of the chamber atmosphere within 15 minutes. After fumigation with a dosage 64 mg L-1 at 6.0 ºC and subsequent storage at 6.0 ºC, mean MB residue content in grapes from among all the packages 24 h after MB fumigation was 6.9 mg kg-1. Residue depuration at 26.7 ºC was similarly rapid.