Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/3/2021
Publication Date: 4/2/2021
Citation: Neven, L.G., Wakie, T.T., Yee, W.L. 2021. The eclosion of Rhagoletis pomonella (Diptera: Tephritidae) under different chill durations and simulated temperate and tropical conditions. Environmental Entomology. 50(3):706-712. https://doi.org/10.1093/ee/nvab018.
Interpretive Summary: The apple maggot fly is a serious pest of apples in North America. This fly overwinters as hibernating (diapausing) pupae in the soil. Emergence of this pest is closely correlated with the availability of host fruit, apples and hawthorns. Researchers at the USDA-ARS in Wapato, WA determined the effects of various durations of chilling and post-chilling temperature, day length, and humidity on the timing of post-diapause emergence. They found that a chill duration of 10 weeks or greater correlated to a synchronized emergence pattern, but that temperature and day length did not greatly impact timing or overall emergence. Results suggest that if introduced into a humid tropical country, apple maggot could produce adult flies, but whether flies could establish would require the presence of suitable host fruit, which are not present in tropical climates
Technical Abstract: The apple maggot fly, Rhagoletis pomonella (Walsh) (Diptera: Tephritidae), is a serious pest of apple in North America that is subject to quarantine measures to prevent its spread to currently pest-free regions, including the tropics. How the fly may survive in warmer climates is unclear. Here, we studied the effects of exposing post-chill puparia to simulated temperate and tropical environmental conditions on eclosion of R. pomonella from Washington State, U.S.A. Puparia were chilled for 0–30 weeks at 3°C and then held under four post-chill conditions: A = 23°C, 16:8 L:D, 40% RH; B = 26°C, 12:12 L:D, 80% RH; C = 26°C, 16:8 L:D, 80% RH; and D = 23°C, 12:12 L:D, 40% RH, with B and D representing tropical conditions and A and C temperate conditions. Within each chill duration, total numbers of flies eclosed were equally high in tropical treatment B and temperate treatment C, while they were lower in treatments A and D. Mean weeks of first eclosion in treatments B and C were earlier than in treatment D; mean week of peak eclosion and 50% eclosion in treatments A, B, and C were earlier than in treatment D. Eclosion spans in treatments A, B, and D were generally shorter than in treatment C. Results suggest that if introduced into a humid tropical country, R. pomonella puparia from Washington State could produce adult flies, regardless of chill duration or lack of chilling during the pupal stage, but whether flies could establish there would require further study