扶桑绵粉蚧的过冷却点和体液结冰点测定

本文测定了扶桑绵粉蚧Phenacoccus solenopsis Tinsley除卵期以外其它各虫态的过冷却点和结冰点.结果表明,该虫过冷却点以1龄若虫最低,为-24.02℃;雄虫预蛹次之,为-22.13℃;雄虫蛹、雄虫2龄若虫、雌虫3龄若虫、雄成虫、雌虫2龄若虫、雌成虫过冷却点逐渐升高,分别为-21.08℃、-20.25℃、-19.05℃、-18.42℃、-17.91℃、-16.89℃.体液结冰点也以1龄若虫最低,为-23.2℃;雄虫预蛹次之,为-19.09℃;雄虫蛹、雄虫2龄若虫、雌虫3龄若虫、雌虫2龄若虫、雌成虫、雄成虫体液结冰点逐渐升高,分别为-16.64%、-15.81℃、-13.92℃、-13.20℃、-12.85℃、-12.79℃.试验结果表明扶桑绵粉蚧过冷却点低,耐寒性较强,可能适宜在中国北部更广泛的区域生存.

Supercooling points and freezing points of mealybug Phenacoccus solenopsis Tinsley

Supercooling points and freezing points of all stages except for egg stage of mealybug Phenacoccus solenopsis Tinsley were determined. The supercooling points of the first instar nymph was the least, as- 24. 02℃ , and that of the male prepupa was the secondary, as - 22. 13℃. Supercooling points of other stages including the male pupa, 2~(nd) instar nymph of the male, 3~(rd) instar nymph of the female, the male, 2~(nd) instar nymph of the female, the female, were - 21. 08℃, - 20. 25℃ , - 19. 05℃ , - 18. 42℃,-17.91℃, -16. 89℃, respectively. Freezing points determined revealed that of I~st instar nymph was least, as -23. 2℃; the secondary, -19. 09℃, was the male prepupa. Freezing points of the male pupa, 2~(nd) instar nymph of the male, 3~(rd) instar nymph of the female, 2~(nd) instar nymph of the female, the female, the male, were -16.64℃, -15.81℃, -13.92℃, -13.20℃, -12. 85℃, -12. 79℃, respectively. The results presented that the supercooling point of P. solenopsis was low, cold hardiness was great, and indicated its widely potential distribution in north China.