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亚洲柑橘木虱Diaphorina citri Kuwayama和柚喀木虱Cacopsylla citrisuga Yang&Li均为柑桔上的重要害虫,前者为黄龙病的主要媒介昆虫,后者也已证实为黄龙病菌的携带者。本文对这两种木虱各龄若虫和成虫的过冷却点和体液结冰点进行了测定,结果表明,柑橘木虱过冷却点和冰点均以1龄若虫最低,平均值分别为-26.32℃和-26.22℃;成虫的过冷却点和冰点最高,分别为-19.60℃和-18.71℃;其它虫态过冷却点和冰点由低到高依次为2龄若虫、4龄若虫、5龄若虫、3龄若虫。柚喀木虱过冷却点和冰点也均以1龄若虫最低,平均值分别为-25.30℃和-25.08℃;5龄若虫的过冷却点和冰点最高,平均分别为-19.50℃和-17.69℃;其它虫态过冷却点和冰点由低到高依次为2龄若虫、3龄若虫、4龄若虫、成虫。两种木虱的比较结果表明,各发育阶段的表现不一致,柚喀木虱的3龄若虫和成虫过冷却点显著低于柑桔木虱,而4龄、5龄若虫则显著高于柑桔木虱;3龄若虫体液结冰点也显著低于柑桔木虱,但1龄、4龄却显著高于柑桔木虱。柑桔木虱雌雄成虫的过冷却点和体液结冰点差异不显著。研究结果表明两种木虱的过冷却点、体液结冰点都较低,因而可能具有较强的耐寒能力。
Diaphorina citri Kuwayama and Cacopsylla citrisuga Yang & Li are all important pests of citrus. The former is the major vector insect of the yellow dragon’s disease, and the latter has also been proved to be the carrier of the yellow dragon’s disease. In this paper, the supercooling point and body fluid freezing point of nymphs and adults of each stage were determined. The results showed that the first instar nymphs were the lowest and the average values were -26.32 ℃ And -26.22 ℃ respectively. The adults had the highest subcooling point and freezing point of -19.60 ℃ and -18.71 ℃, respectively. The other sub-cooling and freezing points of the insect belonged to the 2nd instar nymph, the 4th instar nymph, the 5th instar nymph, 3rd instar nymphs. The first and the first instar nymphs were the lowest at the subcooling point and the freezing point of the citrus psyllids, with the average values of -25.30 ℃ and -25.08 ℃, respectively. The 5th and 5th instar nymphs had the highest subcooling and freezing points with average -19.50 ℃ and -17.69 ℃, respectively ; The other sub-cooling state of the insect and freezing point from low to high were 2 instar nymphs, 3rd instar nymphs, 4th instar nymphs and adult worms. The results of the comparison of the two psyllids showed that the performance at different developmental stages was inconsistent. The 3rd-instar nymphs and adults had significantly lower subcooling points than Citrus psyllid, while the 4th instar and 5th instar nymphs were significantly higher than citrus Picea crassifolia; 3rd instar nymphs also significantly lower body freezing point than citrus psyllid, but the first instar, the fourth instar was significantly higher than the citrus psylla. There was no significant difference between supercooling point and body fluid freezing point of male and female adults of Citrus psyllid. The results showed that both psicillas had lower supercooling points and lower body fluid freezing points, which may have stronger cold resistance.