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环境的温湿度变化对昆虫病原真菌侵染害虫造成直接的影响。本文研究了在不同温湿度变化下,球孢白僵菌Bb2352对梨网蝽和东亚飞蝗侵染率的变化动态与趋势。结果表明,在1.0×107孢子/m L悬浮液接种、25℃饲养条件下,2种不同昆虫的死亡率均随着湿度的增加而增加。经检验湿度效应对死亡率的数量影响吻合时间-剂量-死亡率模型(TDM模型),拟合得到的新的时间-湿度-死亡率(THM)模型能准确地描述球孢白僵菌Bb2352侵染的湿度效应。THM模型显示,当相对湿度达到85%以上时,梨冠网蝽的死亡率增速明显快于蝗虫;梨冠网蝽死亡率随湿度变化的时间效应参数γ在第8 d(γ8)达到最大,而东亚飞蝗死亡率随湿度变化的时间效应参数γ在第11 d(γ11)达到最大,显示出球孢白僵菌Bb2352侵染不同昆虫的湿度效应有所差异。在温度效应研究中,当环境相对湿度>95%时,菌株Bb2352侵染2种目标昆虫的累计死亡率均在25℃达到最大,增加或降低温度均会降低菌株Bb2352的侵染效率。Logistic模型拟合显示该模型能准确反映球孢白僵菌Bb2352侵染目标害虫的温度效应。本文中湿度THM模型和温度Logistic模型的构建是数学描述昆虫病原真菌对害虫侵染温湿度效应的有益尝试。
Environmental changes in temperature and humidity on insect entomopathogenic fungi directly affect the pest. In this paper, we studied the dynamics and trend of the infection rate of Beauveria bassiana Bb2352 to Pestus and Locusta migratoriae under different temperature and humidity changes. The results showed that the mortality of two different insects increased with the increase of humidity under the condition of inoculation of 1.0 × 107 spores / m L suspension and feeding at 25 ℃. The effect of tested humidity on the number of deaths was in good agreement with the time-dose-mortality model (TDM model). The fitted new time-humidity-mortality (THM) model accurately described the behavior of B. bassiana Bb2352 Dyeing humidity effect. The THM model showed that when the relative humidity reached more than 85%, the death rate of Pear's crown bug was significantly faster than that of grasshopper; the time-dependent parameter γ of death rate of Pear's crown bug with humidity reached its maximum on the 8th day (γ8) , While the time-dependent parameter γ of the mortality of Locusta migratoria manilensis with humidity reached the maximum on the 11th day (γ11), indicating that the wetness effects of different doses of B. bassiana Bb2352 on different insects varied. In the temperature-dependent study, when the relative humidity was> 95%, the cumulative mortality of the two target insects infected by strain Bb2352 reached the maximum at 25 ℃. Increasing or decreasing the temperature could reduce the infection efficiency of strain Bb2352. Logistic model fitting showed that the model can accurately reflect the temperature effect of Beauveria bassiana Bb2352 infecting target pests. In this paper, the establishment of humidity THM model and temperature Logistic model is a useful attempt to describe the effects of entomopathogenic fungi on the temperature and humidity effects of pest infestation.