The codling moth, Cydia pomonellaL. (Lepidoptera: Tortricidae), a worldwideapplepest, is classified as a freeze-intolerant organism and one of the most cold-tolerant pests. The objectives of this study wereto examine the supercooling pointof overwintering and non-diapausing larvae of C. pomonellaas an index of its cold hardiness,and to assess larval mortality following 24 h exposureto extreme low temperatures ranging from –5 to –25°C. The mean (±SE) supercooling pointfor feeding larvae (third through fifth instars) was –12.4 ±1.1°C. The mean supercooling pointfor cocooned,non-diapausing larvae (i.e., non-feeding stages) decreased as the days that the larvae were cocooned increased and changed between –15.1 ±1.2°C for one to two day cocooned larvae and –19.2 ±1.8°C for less than five day cocooned larvae. Themean (±SE) supercooling pointfor other non-feeding stages containing pupae and overwintering larvae were –19.9 ±1.0°C and –20.2 ±0.2°C, respectively. Mean supercooling points of C. pomonellalarvae were significantly lower during the winter months than the summer months, and sex had no effect on the supercooling pointof C. pomonellalarvae. The mortality of larvae increased significantly after individuals were exposed to temperatures below the mean supercooling point of the population. The supercoolingpoint was a good predictor of cold hardiness.
کلید واژگان :codling moth, diapause, freeze-intolerant insect, low temperature
ارزش ریالی : 600000 ریال
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