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United States Department of Agriculture

Agricultural Research Service

Research Project: Pre and Postharvest Treatment of Tropical and Other Commodities for Quarantine Security, Quality Maintenance, and Value Enhancement

Location: Tropical Crop and Commodity Protection Research

Title: Influence of modified atmosphere packaging on radiation tolerance in the phytosanitary pest melon fly, Bactrocera cucurbitae (Diptera Tephritidae)

Authors
item Follett, Peter
item Wall, Marisa
item Woodward, Bailey -

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 10, 2013
Publication Date: October 11, 2013
Citation: Follett, P.A., Wall, M.M., Woodward, B. 2013. Influence of modified atmosphere packaging on radiation tolerance in the phytosanitary pest melon fly, Bactrocera cucurbitae (Diptera Tephritidae). Journal of Economic Entomology. 106(5):2020-2026.

Interpretive Summary: Modified atmosphere packaging (MAP) produces a low oxygen environment which helps preserve produce quality. Insect are more tolerant to irradiation in a low oxygen environment. This calls into question the use of MAP when fruit are exported using irradiation to control quarantine insect pests. Melon fly is an important economic and quarantine pest of tropical fruits and vegetables, and one of the most radiation tolerant tephritid fruit flies known. The effect of MAP on the radiation tolerance of melon fly was examined. Third instar melon fly larvae were inoculated into ripe papayas and treated by (1) MAP + irradiation (2) irradiation alone, (3) MAP alone, or (4) no MAP and no irradiation, and held for adult emergence. Three types of commercially available MAP products were tested that produced oxygen concentrations from 1-15%, and sublethal radiation doses (43-64 Gy) were used to allow comparisons between treatments. Ziploc® storage bags (1-4% O2) increased survivorship to adult from 14 to 25%, whereas Xtend® PP61 bags (3-8% O2) and Xtend® PP53 bags (11-15% O2) did not enhance survivorship to the adult stage in irradiated melon fly. Radiation doses approved by the United States Department of Agriculture and the International Plant Protection Commission for melon fly and Medfly respectively are 150 Gy and 100 Gy, respectively. In large-scale tests, 9,000 melonj flyand 4,800 Medfly larvae infesting papayas in Ziploc bags were irradiated at 150 Gy and 100 Gy, respectively, with no survivors to the adult stage. MAP can increase insect survivorship during irradiation treatment at certain doses and O2 concentrations. MAP should not compromise the efficacy of the 150 Gy generic radiation treatment for tephritid fruit flies or the 100 Gy radiation treatment for Medfly due to inherent overkill at these doses.

Technical Abstract: Modified atmosphere packaging (MAP) producing a low oxygen environment to increase produce shelf life may increase the radiation tolerance of insect pests receiving phytosanitary irradiation treatment on traded agricultural commodities. Melon fly, Bactrocera cucurbitae (Diptera: Tephritidae) is an important economic and quarantine pest of tropical fruits and vegetables, and one of the most radiation tolerant tephritid fruit flies known. The effect of MAP on the radiation tolerance of B. cucurbitae was examined. Third instar larval B. cucurbitae were inoculated into ripe papayas and treated by (1) MAP + irradiation (2) irradiation alone, (3) MAP alone, or (4) no MAP and no irradiation, and held for adult emergence. Three types of commercially available MAP products were tested that produced oxygen concentrations from 1-15%, and sublethal radiation doses (43-64 Gy) were used to allow comparisons between treatments. Ziploc® storage bags (1-4% O2) increased survivorship to adult from 14 to 25%, whereas Xtend® PP61 bags (3-8% O2) and Xtend® PP53 bags (11-15% O2) did not enhance survivorship to the adult stage in irradiated B. cucurbitae. Radiation doses approved by the United States Department of Agriculture and the International Plant Protection Commission for B. cucurbitae and Ceratitis capitata (Mediterranean fruit fly) are 150 Gy and 100 Gy, respectively. In large-scale tests, 9,000 B. cucurbitae and 4,800 C. capitata larvae infesting papayas in Ziploc bags were irradiated at 150 Gy and 100 Gy, respectively, with no survivors to the adult stage. MAP can increase insect survivorship during irradiation treatment at certain doses and O2 concentrations, but should not compromise the efficacy of the 150 Gy generic radiation treatment for tephritid fruit flies or the 100 Gy radiation treatment for C. capitata.

Last Modified: 12/21/2014
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