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ARS Home » Research » Publications at this Location » Publication #142023


item Follett, Peter
item Lower, Robert

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/25/2000
Publication Date: 8/25/2000
Citation: N/A

Interpretive Summary: Rambutan, lychee, and longan are hosts for the quarantine pest Cryptophlebia in Hawaii. They are also hosts for pest fruit flies and therefore must receive a quarantine treatment before export. Irradiation with a minimum dose of 250 Gy is an approved treatment for fruit flies. We tested whether this treatment will also disinfest fruit of Cryptophlebia.

Technical Abstract: Cryptophlebia illepida (Butler) and C. ombrodelta (Lower) (Lepidoptera: Tortricidae) are quarantine pests of lychee, Litchi chinensis Sonn., and longan, Dimocarpus longan (Lourd.) Steud., in Hawaii that potentially can interrupt export shipments. Irradiation with a minimum absorbed dose of 250 Gy is an approved quarantine treatment developed to disinfest fruit of tephritid fruit flies. Studies were undertaken to determine whether this irradiation treatment would also disinfest fruit of any Cryptophlebia. C. illepida was determined to be more tolerant of irradiation than C. ombrodelta, and so C. illepida was the focus for detailed tests. Eggs (3-d-old), larvae (neonates, second/third instars, and fourth/fifth instars), and pupae were irradiated at various target doses and adult emergence. Fecundity and fertility were measured. Using the criterion of success in developing to the adult stage, the pattern of tolerance to irradiation in C. illepida was generally eggs 125 Gy. In large scale tests, when 11,256 late instars were irradiated with a target dose of 250 Gy, 951 pupated (8.4%) and none eclosed as adults. Within the pupal stage, tolerance increased with age; 7-8-d old pupae (the oldest pupae tested) treated with an irradiation dose of 125 Gy produced viable offspring, whereas those treated with a dose of 250 Gy produced no viable offspring. Irradiation with a target dose of 250 Gy of adults before pairing and mating, and ovipositing adult females, resulted in no viable eggs. Therefore, the irradiation quarantine treatment of a minimum absorbed dose of 250 Gy approved for Hawaii's fruits will effectively disinfest fruits of any Cryptophlebia in addition to fruit flies.