Study on Larval Diapause Development of Kermes Quercus （Linnaeus） （Hemiptera： Kermesidae） in Warsaw, Poland

This research presents new information on the biology ofKermes quercus （L.）. Observations were carried out in 2009 in the city of Warsaw and surroundings （Poland）. Material was collected on Quet;cus robur L. between the end of January until the beginning of November. The sampling each month was divided into three ten-day periods： I - from the 1st till 10th day of the month, II - from ! lth till 20th day of the month, and Ill - from 21st till 30th day of the month. The material was sampled at least once in each period. All live specimens of K. quercus were picked off and the developmental stages were identified. The observations revealed that, almost exclusively lst-instar nymphs occurred during the winter and they remained in this stage throughout the spring and summer until the last third of August. The process of moulting from 1st instar to 2nd instars started in the last third of August and lasted about 2 weeks. In autumn the 2nd-instars nymphs entered the winter diapause. The results suggest that, under the climatic conditions of Poland, Kermes quercus L. is not a univoltine species. Each generation probably develops through two years - in the first year overwintering as the lst-instar nymphs and in the second year as the 2nd-instar nymphs.