Submitted to: CryoLetters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/19/2000
Publication Date: 10/15/2000
Citation: Neven, L.G., Ferguson, H.J., Knight, A.L. 2000. Sub-zero cooling synchronizes post-diapause development of codling moth, Cydia pomonella. CryoLetters. 21:203-214. Interpretive Summary: Rearing codling moth in the laboratory is both expensive and labor intensive. It would be more economical if the insects could be stockpiled and stored for use during the growing season when the need for these insects are the highest. Other research has indicated that moths from diapausing (hibernating) larvae are not as long lived, show poor mating success, and produce fewer eggs than insects which have not been in diapause. Also, moth emergence is spread out over a long time period which is not conducive to mass rearing. Subjecting diapausing larvae to sub-zero temperatures of -10 and -15 deg C helps to synchronize post-diapause development without loss of longevity, matting success, egg production, or egg hatch. This method may be used to optimize mass rearing of codling moth.
Technical Abstract: Sub-zero cooling treatments of -10 deg C and -15 deg C for 2-6 days were evaluated as a means of meeting the chilling requirement of diapause and to synchronize post-diapause development in larvae which were held in diapause for less than 6 months. Diapause/cooled males and females were, in general, longer lived than diapause control and non-diapause control adults. There were no differences in the number of spermatophores transferred among the treatment groups. Sub-zero cooling resulted in higher fecundity and fertility rates for males than females. Sub-zero cooling of insects in diapause for 7 months resulted in higher oviposition for both sexes. There were no differences in egg hatch rates among the treatment groups. The duration of sub-zero cooling had a significant effect on post-diapause emergence in relation to the duration that the larvae were in diapause. Sub-zero cooling for 4 days at -10 deg C significantly reduced the amount of time to adult emergence of larvae that had been in diapause for 0-4 months. Sub-zero cooling at -15 deg C for durations of 2, 4, and 6 days had more variable results on emergence, but in most cases, sub-zero cooling reduced the amount of time to and span of adult emergence.