Vapor heat treatment for quarantine control of the oriental fruit fly (Diptera: Tephritidae) in papaya fruit from Thailand

Authors: SRIMARTPIROM, M - Department Of Agriculture - Thailand; RAKKRAI, C - Department Of Agriculture - Thailand; PHANKUM, S - Department Of Agriculture - Thailand; INTARAKAMHANG, R - Department Of Agriculture - Thailand; SONSIRI, C - Department Of Agriculture - Thailand; BUCHATIAN, P - Department Of Agriculture - Thailand; PHANGLERK, P - Department Of Agriculture - Thailand; JINNALITE, P - Department Of Agriculture - Thailand; KHONGTHAWIE, S - Department Of Agriculture - Thailand; UNAHAWUTTI, U - Department Of Agriculture - Thailand; Follett, Peter

Submitted to: Journal of Asia-Pacific Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/21/2023
Publication Date: 2/3/2023
Citation: Srimartpirom, M., Rakkrai, C., Phankum, S., Intarakamhang, R., Sonsiri, C., Buchatian, P., Phanglerk, P., Jinnalite, P., Khongthawie, S., Unahawutti, U., Follett, P.A. 2023. Vapor heat treatment for quarantine control of the oriental fruit fly (Diptera: Tephritidae) in papaya fruit from Thailand. Journal of Asia-Pacific Entomology. 26(2). Article 102049. https://doi.org/10.1016/j.aspen.2023.102049.
DOI: https://doi.org/10.1016/j.aspen.2023.102049

Interpretive Summary: A vapor heat treatment (VHT) was developed in Thailand to disinfest papayas of oriental fruit fly, Bactrocera dorsalis. The treatment involves heating papaya fruit to 47 0C and holding for 20 min. The first instar of oriental fruit fly was determined to be the most heat tolerant life stage. In large scale confirmatory tests, 78,405 oriental fruit fly first instars in papaya fruit were treated with VHT with no survivors to the adult stage. This VHT may allow Thailand to export papayas to the EU and other foreign markets.

Technical Abstract: A two-stage vapor heat treatment (VHT) is used commercially for disinfestation of the oriental fruit fly (OFF), Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) in various tropical fruits exported from Thailand to international markets. In the present study, VHT was tested against B. dorsalis in papayas to confirm a probit 9 level of quarantine security. The first instar larva of B. dorsalis was the most heat tolerant life stage. The VHT consists of heating papaya fruits with hot air at 50-80 % RH from ambient temperature to a fruit center temperature of 43 oC (dry pre-heating period), then heating with saturated hot air to 47 oC (wet heating period) with a 20-min hold at 47 oC. In large-scale confirmatory tests of this VHT treatment schedule, none of the treated 78,405 first instar larvae survived. Papayas at the color break maturity stage treated by VHT and held under simulated commercial export conditions showed no differences in fruit quality compared with non-treated controls. VHT showed high efficacy in disinfestation of papayas of B. dorsalis while maintaining fruit quality and could be used as a standard quarantine treatment for papaya exported from Thailand.