幼虫密度对粘虫抵抗苏云金芽孢杆菌和球孢白僵菌侵染能力的影响
Effects of larval density on resistance of Mythimna separata larvae to Bacillus thuringiensis and Beauveria bassiana
孔海龙 袁 琳 董传磊 郑敏圆 荆王辉 田 振 侯秋莉
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DOI：10.7679/j.issn.2095-1353.2020.146
作者单位：扬州大学园艺与植物保护学院，扬州 225009；扬州大学园艺与植物保护学院，扬州 225009；扬州大学园艺与植物保护学院，扬州 225009；扬州大学园艺与植物保护学院，扬州 225009；扬州大学园艺与植物保护学院，扬州 225009；扬州大学园艺与植物保护学院，扬州 225009；扬州大学园艺与植物保护学院，扬州 225009
中文关键词：粘虫；苏云金芽孢杆菌；球孢白僵菌；幼虫密度；抗病能力
英文关键词：Mythimna separata; Bacillus thuringiensis; Beauveria bassiana; larval density; disease resistance
中文摘要：
【目的】 明确粘虫Mythimna separata幼虫不同密度下抗病能力的变化规律。【方法】 在室内条件下，采用叶片药膜法与浸虫法，对不同密度（1、2、5、10、30头/瓶（650 mL））饲养的粘虫幼虫抵抗苏云金芽孢杆菌（Bacillus thuringiensis，Bt）和球孢白僵菌（Beauveria bassiana）侵染的能力进行研究。【结果】 不同粘虫幼虫密度对接种苏云金芽孢杆菌及球孢白僵菌后幼虫的存活率和存活时间影响显著。随着幼虫密度的增加，苏云金芽胞杆菌侵染的幼虫存活率明显升高、存活时间显著延长，幼虫存活率以10头/瓶的最高，显著高于1头/瓶和2头/瓶的；幼虫存活时间以30头/瓶的最长，明显长于1头/瓶、2头/瓶、5头/瓶的。同时，随着幼虫密度的升高，球孢白僵菌与苏云金芽孢杆菌侵染的幼虫存活率、存活时间变化趋势相同，高密度幼虫的存活率和存活时间均显著高于低密度的幼虫。【结论】 幼虫密度是影响粘虫幼虫抗病性变化的重要因子，且高密度幼虫的抗病能力明显高于低密度幼虫。
英文摘要：
[Objectives] To clarify the dynamics of disease resistance
in Mythimna separata larvae reared at different larval densities. [Methods] The resistance of larvae to Bacillus thuringiensis (Bt) and Beauveria bassiana at densities of 1, 2,
5, 10 and 30 larvae per jar were tested by the membrane method and the
immersion method in a laboratory. [Results] Larval density had significant effects on the
survival rate and survival time of larvae infected with Bt and B. bassiana. At
higher larval densities the survival rate and survival time of larvae infected
with Bt significantly
increased. The survival rate was highest at a density of 10 larvae per jar,
which was significantly higher than that at densities of 1 and 2 larvae per
jar. The larval survival time was longest at a density of 30 larvae per jar,
which was significantly longer than that at 1, 2 and 5 larvae per jar. The
trend in survival rate and survival time of larvae infected with Bt at
different densities was consistent with that of larvae infected with B. bassiana. The survival rate and
survival time of larvae at high densities were significantly higher than that
of larvae at low densities. [Conclusion] Larval density has an important effect on
disease resistance in M. separata;
larvae have significantly greater resistance at higher than at lower densities.