美洲斑潜蝇的越冬与耐寒性研究

ON THE OVERWINTERING AND COLD-HARDINESS OF THE VEGETABLE LEAFMINER LIRIOMYZA SATIVAE BLANCHARD

美洲斑潜蝇蛹的过冷却点为-9.96℃,结冰点为-9.06℃,远高于南美斑潜蝇蛹的过冷却点-19.55℃和结冰点-18.70℃。夏季蛹和秋季蛹的过冷却点无显著差异。发育末期蛹的过冷却点明显高于发育初、中期蛹。不同低温条件下蛹的耐寒能力不同,3d期蛹在-15、-10、0和4～8℃下致死中时分别为0.14、42.19、132.24和432.72h,死亡率回归方程分别为Y=2.1603+3.0487X、Y=-6.9430+7.3485X、Y=2.9916+2.7103X及Y=0.1403+3.8689X。美洲斑潜蝇在北京地区田间自然条件下不能越冬。

The supercooling points (SCP) and the freezing points (FP) of the vegetable leafminer L. sativae Blanchard pupae were -9. 96 ℃ and -9. 06 ℃ , respectively, which were greatly higher than those ( - 19. 55℃ , -18. 70 ℃) of L. huidobrensis. No difference in SCP and FP was found between summer pupae and autumn pupae. The SCP of the pupae in the late developmental phase was significantly higher than those of the pupae in the early and middle phases. The cold-hardiness varied under different low temperatures. The 50% lethal time (LT50) of the pupae , after incubated for three days under 25 ℃, treated under -15, -10, 0 and 4 -8℃ was 0 . 14, 42. 19, 132. 24 and 432. 72h, respectively. The regression equations between mortality (Y) and time (X) were Y = 2. 1603 + 3. 0487X, Y= -6. 9430 + 7. 3485X, Y = 2. 9916 + 2. 7103X and Y = 0. 1403 + 3. 8689X, respectively. The pupae of L. sativae were unable to overwinter outdoors in Beijing.