不同温度梯度及频率的冻融对冬型中国梨木虱存活的影响

Effects of freezing and thawing in different frequency and temperature gradients on the survival of winterform pear psylla

为明确冻融对冬型中国梨木虱存活的影响,本研究在测定冬型中国梨木虱过冷却点及-20℃低温下的存活情况的基础上设计了4组冻融梯度(-20℃/2℃、-20℃/5℃、-20℃/10℃、-20℃/20℃),3组频段(1、2、3 h),以探索迅速冻融对冬型中国梨木虱存活的影响。结果表明:冬型梨木虱的过冷却点主要分布在-14℃~-12℃;-20℃条件下其致死中时LT 50为6.9 h;冬型梨木虱经历6次1 h间断冻融处理后其死亡率显著低于3次、2次处理和持续低温处理;冬型梨木虱在-20℃/10℃、-20℃/20℃的温度梯度处理下死亡率显著低于-20℃/2℃、-20℃/5℃处理。本研究结果表明,迅速冻融间断时间越短、频率越高,越利于冬型梨木虱存活;冻融温度梯度越大,其存活率越高。该研究结果有助于了解冬型梨木虱适应极端及突变温度的能力,对预测其越冬存活、种群数量监测及防控具有理论指导意义。

In order to investigate the effects of freezing and thawing on the survival of winterform pear psylla,based on the determination of the supercooling point(SCP)and mortalities at-20℃,four freezing-thawing gradients(-20℃/2℃,-20℃/5℃,-20℃/10℃,-20℃/20℃)and three frequencies(1,2,3 h)were designed to explore the effects of rapid freezing-thawing on the survival of winterform pear psylla.The results showed that the supercooling points of winterform pear psylla were mainly distributed from-14℃to-12℃;the median lethal time(LT 50)of pear psylla was 6.9 h at-20℃;the mortalities of winterform pear psylla after rapid freezing-thawing treatments for six times at a 1 h interval were significantly lower than for three or two times followed by continuous low-temperature treatment;the mortalities under the temperature gradients of-20℃/10℃and-20℃/20℃were significantly lower than that under-20℃/2℃and-20℃/5℃.It indicted that the shorter of the interval for rapid freezing and thawing plus higher frequency would benefit the survival of winterform pear psylla,and the greater the difference in the gradient of freezing-thawing temperature,the higher the survival rate.The results of this study are helpful for understanding the ability of winterform pear psylla to adapt to the extreme conditions and sudden temperature changing,and can provide a theoretical guidance for predicting its survival,monitoring,and control of pear psylla.