• Korean journal of applied entomology
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• v.52 no.4
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• pp.349-356
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• 2013

A set of experiments were conducted to determine the zero temperature and total effective temperature for the summer diapause and post-diapause development of Matsucoccus thunbergianae Miller et Park (Hemiptera: Margarodidae) which infests the Japanese black pine, Pinus thunbergii. The diapausing first instar nymphs were kept in cool storage during three separate times, each starting from May 4th, June 19th, and August 15th of 2002. Cool storage temperatures were 2.5, 5.0, 7.5, 10.0, 12.5 and $15.0^{\circ}C$. The nymphs were chilled for 10, 20, 30 or 40 days in the first two sets of experiments. In the third experiment, nymphs were chilled for 3, 6, 9 or 12 days. Molting into the second instar nymphs was examined every 10 days, starting at 20 days after taken out from the cool storage. Optimum temperature range of the diapause development was between 7.5 and $10^{\circ}C$, where diapause development was completed in 40, 20, and 6 days by the insects chilled from May 4th, June 19th and August 15th, respectively. Comparing the three sets of experiments with different chilling periods, zero temperature for diapause development was calculated as $29^{\circ}C$. Effective temperature for diapause development was 964 degree days, and it was estimated that nymphs completed their diapause development by September 8th in nature. Under natural temperature conditions >50% eclosion into the second instar occurred on November 9th. Zero temperature for post-diapause development was $10^{\circ}C$, and total effective temperature for post-diapause development until the molt into the second instar was 391 degree days.