土壤含水量及蛹室对甜菜夜蛾蛹越冬的影响
Effects of soil moistures and pupal chamber on overwintering of Spodoptera exigua
郑霞林 王 攀 丛晓平 雷朝亮 王小平**
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作者单位：华中农业大学植物科学技术学院，湖北省昆虫资源利用与害虫可持续治理重点实验室 武汉 430070
中文关键词： 甜菜夜蛾， 蛹， 土壤含水量， 蛹室， 越冬
英文关键词： Spodoptera exigua,pupae,soil moisture,pupal chamber,overwintering
中文摘要：研究了自然条件下土壤含水量和蛹室对甜菜夜蛾Spodoptera exigua Hübner蛹越冬的影响，发现蛹在自然蛹室中能存活30 d以上（不超过60 d）。处理15 d，随着土壤含水量的变化，蛹的存活率分别降至80 %、20 %和43 %。但处理30、60、90 和120 d时死亡率均达到100%。调查发现，随着处理时间的延长，各土壤含水量中所埋的蛹死亡特征均有一个相同趋势，即发黑、发霉——肿胀——腐烂——残留部分蛹体。不同土壤含水量条件下，蛹的过冷却点、结冰点和蛹体含水量间均存在显著性差异（P≤0.05），尤以在最低的土壤含水量条件下蛹的过冷却点、结冰点和蛹体含水量最低，分别为(-20.2±1.1) ℃、(-11.95±2.5) ℃ 和(57.6±7.7)%。在室外变温条件下，结果初步表明蛹室对蛹有一定的保护作用。
英文摘要：Effects of soil moisture and pupal chamber characteristics on the overwintering of Spodoptera exigua Hübner were studied in the field in Wuhan District.S.exigua pupae could survive more than 30 days in natural pupal chambers.After 15 days the survival rate of pupae exposed to high,moderate and low soil moisture levels decreased to 80%,20% and 43% respectively.No pupae survived longer than 60 days.Extension of the treatment time over 60 days caused pupae to blacken,swell and decay until only a residual puparium remained.The pupal supercooling point (SCP),freezing point (FP) and body water content (BWC) differed significantly between the three different soil moisture levels (P ≤ 0.05).SCP,FP and BWC were the lowest (-20.2±1.1) ℃,（-11.95±2.5）℃ and (57.6±7.7) % respectively at the lowest soil moisture level.The pupal chamber evidently provides essential protection required for pupae to overwinter in field.