水稻大螟越冬幼虫寄生蜂种类调查与主要寄生蜂越冬动态分析

大螟Sesamia inferens(Walker)是水稻上一种重要的钻蛀性害虫，其寄主范围广，近年来为害加重。由于长期以来对大螟的防治采取兼治策略，大螟已经对多种农药产生了抗性。因此，掌握水稻大螟生物防治资源有重要的应用意义。本研究报道了江苏扬州地区水稻大螟越冬幼虫体内仅有两种寄生蜂，分别是中华茧蜂Amyosoma chinensis和螟黄足盘绒茧蜂Cotesia flavipes,其中螟黄足盘绒茧蜂是优势种群。通过近三年的系统调查发现：在自然界中螟黄足盘绒茧蜂在大螟越冬幼虫体内的寄生率呈现动态变化，最高寄生率达33.33%,并且不同年份之间有差异。螟黄足盘绒茧蜂最短出茧时间仅为5.0 d,最长不超过14.0 d。除了12月份至次年1月份采集的螟黄足盘绒茧蜂外，其它时间点采集到的螟黄足盘绒茧蜂的羽化率高达75%以上。该研究结果为利用螟黄足盘绒茧蜂防治大螟提供了研究基础。

Investigation on the species of parasitic wasps in the overwintering larvae of Sesamia inferens (Walker) and analysis of the overwintering dynamics of the key parasitic wasps

Sesamia inferens (Walker) is an important borer pest on rice with a wide range of hosts, and its damage has been aggravated in recent years. Now, S. inferens has developed resistance to a variety of pesticides due to the long-term prevention and treatment strategy. Therefore, it is of important application significance to master the biological control resources of S. inferens. This study reported that there were only two parasitic wasps in the overwintering larvae of S. inferens in Yangzhou, Jiangsu-Amyosoma chinensis and Cotesia flavipes, and the latter was the dominant parasitic species. Through the systematic investigation of the past three years, it was found that the parasitism rate of C. flavipes in nature in the overwintering larvae of S. inferens showed a dynamic change, and the highest parasitism rate could reach 33.33%. Also, there were differences between different years. The shortest time to emerge from the cocoon was only 5 days, and the longest did not exceed 14 days. Except for the C. flavipes collected from December to January of the following year, the emergence rate of C. flavipes collected at other time could reach to 75% or even higher. The results of this study provided a research basis for the use of C. flavipes to prevent the occurrence of S. inferens.