Author
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Hallman, Guy |
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Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 3/15/2004 Publication Date: 6/21/2004 Citation: Hallman, G.J. 2004. Ionizing irradiation quarantine treatment against oriental fruit moth (Lepidoptera: Tortricidae) in ambient and hypoxic atmospheres. Journal of Economic Entomology. 97:824-827. Interpretive Summary: Oriental fruit moth, Grapholita molesta is a pest of many fruits, including apples, pears, plums, and peaches, in much of the world. However, some areas are free of the pest, and shipments of fruit hosts from infested to non-infested areas may be regulated. Current quarantine treatments for oriental fruit moth include methyl bromide fumigation and cold storage for several weeks. Methyl bromide use is being restricted because it is a stratospheric ozone-depleting substance and alternatives are sought. Cold is not tolerated by many hosts of oriental fruit moth, such as peaches and plums. The objective of this research was to develop irradiation quarantine treatments against the pest under low oxygen and normal atmospheric storage conditions because some hosts of oriental fruit moth are stored in low oxygen atmospheres and this is known to lessen the effects of irradiation. In normal atmospheres, no adults emerged from 58,779 fifth instar larvae (the most radiation-tolerant stage present in fruit) irradiated with 200 Gy. In atmospheres flushed with nitrogen (low oxygen), 5.3% of adults emerged from 44,050 fifth instars at 200 Gy, but they died at a faster rate than control adults, and without laying eggs. A dose of 232 Gy (the maximum recorded when 200 Gy was targeted) is recommended to disinfest any fruit of oriental fruit moth in normal and low oxygen atmospheres. Technical Abstract: Oriental fruit moth, Grapholita molesta (Busck), is a pest of many rosaceous temperate fruits, including pomes, Malus spp., and stone fruits, Prunus spp., in much of the world. However, some areas are free of the pest, and shipments of fruit hosts from infested to non-infested areas may be regulated. Current quarantine treatments for oriental fruit moth include methyl bromide fumigation and cold storage for several weeks. Methyl bromide use is being restricted because it is a stratospheric ozone-depleting substance and alternatives are sought. Cold is not tolerated by many hosts of oriental fruit moth. The objective of this research was to develop irradiation quarantine treatments against the pest under ambient and hypoxic storage conditions because some hosts of oriental fruit moth are stored in hypoxic atmospheres and hypoxia is known to lessen the effects of irradiation. In ambient atmospheres, no adults emerged from 58,779 fifth instars (the most radiotolerant stage present in fruit) irradiated with a target dose of 200 Gy (195-232 Gy measured). In atmospheres flushed with nitrogen, 5.3% of adults emerged from 44,050 fifth instars irradiated with a target dose of 200 Gy (194-230 Gy measured), but they died at a faster rate than control adults and without laying eggs. A dose of 232 Gy (the maximum recorded when 200 Gy was targeted) is recommended to disinfest any fruit of oriental fruit moth under ambient and hypoxic atmospheres. |
