Abstract:The pine armored scale, Hemiberlesia pitysophila Takagi is a dangerous pine forest pest which mainly attacks needle leaves, cones and twigs of various evergreen pines, and has led to great damage in south China since early 1980s. The parameters of supercooling point (SCP), mortality exposed to designated low temperature (ME), discriminating temperature (DT) and median lethal sum of low temperature (LST50) of the pest collected in different seasons in Quanzhou, Fujian Province, China from 2007 to 2008 were measured and compared. The results showed that individual SCP of this pest fluctuated from -22.4 ℃ to -3.1 ℃. Among all the developmental stages of the pest in every season, winter female adults had the lowest SCP with the mean value of -14.83 ℃, which was significantly lower than those of summer female adults, winter newly hatched nymph and 1st instar nymph （P＜0.01）. However, SCPs of other developmental stages in winter and summer all showed no markedly differences （P＞0.05）. Experiments exposed to low temperature indicated that the parameters of ME, DT and LST50 of 1st instar nymph, 2nd instar nymph before sex differentiation, 2nd instar male nymph after sex differentiation, female adults and population were all obviously lower in winter than in summer. A linear correlative analysis showed that there were significantly positive correlations between seasonal mean air temperature and LST50s of 1st instar nymph, 2nd instar male nymph after sex differentiation and the pest population (R＞R0.05=0.950，n-2=2), but no significant correlations between SCPs and LST50s in each developmental stage (R＜R0.05=0.950，n-2=2). Therefore, it is concluded that the cold tolerance of H. pitysophila population seems to peak in winter and drop in summer. The adaptability to low air temperature in winter may be independent of SCP, but is nearly correlative with seasonal mean air temperature.