温湿度对稻纵卷叶螟卵的联合作用

为了探讨温湿度在稻纵卷叶螟Cnaphalocrocis medinalis （Guenée）种群发展中的作用， 通过室内实验调查了不同温度和湿度组合下该蛾卵的发育历期、 胚胎发育情况、 孵化率和卵粒重量的变化。结果表明： 在相同温度下卵历期随相对湿度的增大而缩短， 孵化率随相对湿度的加大而提高。在22℃下低于46%的相对湿度显著降低了卵的孵化率， 而在25～34℃下低于66%的相对湿度会引起孵化率的显著降低， 37℃下卵无论在何种湿度中均不能孵化。在50%左右的低湿条件下， 温度高于28℃后卵也不能孵化。温度在22～31℃和相对湿度在77%～100%范围内， 卵的孵化率无显著差异， 这属于稻纵卷叶螟卵的适宜温湿度范围。稻纵卷叶螟卵的发育起点温度和有效积温分别为10.1±0.6℃和63.7±3.5日度。卵的孵化率（Y）与温湿系数（RH/T）间呈显著的逻辑斯蒂曲线关系Y=0.8662/1+exp(17.4084-7.5714×RH/T)]。温湿系数在2.34以下时卵孵化率将低于50%， 而达到3.0左右时孵化率接近最高值。结论认为， 低湿造成的稻纵卷叶螟卵重量显著降低、 卵粒干瘪、 胚胎发育受阻是致死卵的主要原因。

Combined effects of temperature and relative humidity on eggs of the rice leaf folder, Cnaphalocrocis medinalis (Lepidoptera: Pyralidae)

In order to explore the roles of temperature and relative humidity in population development of the rice leaf folder, Cnaphalocrocis medinalis (Guenée), the duration, embryo development, hatchability and weight loss of eggs of this moth under different temperature and relative humidity were investigated in the laboratory experiments. The results showed that egg duration significantly shortened and egg hatchability significantly increased as relative humidity increased. Egg hatchability significantly reduced when relative humidity was less than 46% and 66% at 22℃ and 25-34℃, respectively, and no eggs were hatched at 37℃ under any relative humidity (46%-100%). Under the conditions of relative humidity less than 50% and temperature higher than 28℃, all eggs could not be hatched either. The optimal temperature and relative humidity ranges for rice leaf folder eggs were 22-31℃ and 77%-100%, respectively. The lower threshold temperature for development and effective accumulated temperature of eggs were 10.1±0.6℃ and 63.7±3.5 day degrees, respectively. The relationship between egg hatchability (Y) and the ratio of relative humidity to temperature (RH/T) fitted the logistic model very well, Y=0.8662/［1+exp(17.4084-7.5714×RH/T)］. When the RH/T value was less than 2.34, egg hatchability would be less than 50%. The optimal RH/T was about 3.0 for eggs. It is concluded that the higher weight loss of eggs, egg wizening and an arrested development of embryo resulted from lower humidity are the main lethal factors of eggs.