纯磷化氢熏蒸对桃小食心虫的毒力作用

桃小食心虫在我国温带水果主产区广泛分布,严重威胁水果出口贸易。为明确纯磷化氢熏蒸处理桃小食心虫的可能性,本文系统研究了纯磷化氢在不同温度条件下对桃小食心虫的毒力。耐受性分析结果表明,桃小食心虫各虫态对磷化氢的耐受力有很大差别,1~2龄幼虫耐受性最弱,5龄老熟幼虫耐受性最强。室内毒力试验结果表明,25℃,0.14~0.70mg/L磷化氢熏蒸5龄老熟幼虫81~199h或15℃,0.28~0.84 mg/L磷化氢熏蒸136~166h,桃小食心虫死亡率可达99%;在25℃和15℃下,试虫达到一定死亡率的气体浓度、时间乘积(CT)关系式分别为k=C0.5 T和k=C0.2 T,说明在本试验所取浓度范围内,处理时间是影响磷化氢对桃小食心虫老熟幼虫毒力作用的主要因素,相同条件下高温比低温更有利于磷化氢熏蒸杀虫。本文首次对不同温度条件下纯磷化氢熏蒸桃小食心虫的毒力作用进行了系统研究,明确了纯磷化氢熏蒸技术在水果携带桃小食心虫的检疫处理中极具应用前景。

Toxicity of pure phosphine to Carposina sasakii Matsumura (Lepidoptera: Carposinadae)

Carposina sasakii Matsumura (Lepidoptera:Carposinadae),widely distributed in pome fruit production areas in China,seriously threatens fruit export industry.In order to determinate the eliminated doses of pure phosphine against these pests for quarantine purpose,1-d,2-d,3-d-old eggs and the first to fifth instar of C . sasakii larvae were fumigated with pure phosphine.The results showed that mature fifth instar were the most tol-erant stage at room temperature.Then the mature fifth instar larvae of C .sasakii was fumigated over phosphine at different concentrations under different temperatures.0.14,0.28,0.42,0.56,0.70 mg/L phosphine fumiga-tion with 81-199 h period was required and 0.28,0.42,0.56,0.70,0.84 mg/L phosphine fumigation with 136-166 h period was required to achieve 99% mortality at 25℃ and 15℃,respectively.The expressions of k =C 0.5 T and k =C 0.2 T were obtained at 25℃ and 15℃,which indicated that exposure time was much more important than the concentration of phosphine to mortality of mature larvae of C .sasakii .In the similar conditions,higher temperature in environment was more effective to fumigation than lower temperature.All the results suggested that pure phosphine fumigation demonstrated promising application in C .sasakii control in fruit industry.