永州广聚萤叶甲和豚草卷蛾的种群动态及对豚草的控制效果

【目的】豚草是一种重要的入侵杂草,严重危害农业生产和人类健康。广聚萤叶甲和豚草卷蛾是豚草的专一性天敌。研究这2种天敌在永州的种群动态及其对豚草的控制效果,可以为永州豚草的防控及这2种天敌的有效利用提供依据。【方法】在湖南省永州市江永县豚草大面积发生区域,人工释放广聚萤叶甲和豚草卷蛾,调查这2种天敌在释放区和扩散区的种群动态和对豚草的防治效果,以及这2种天敌在扩散区的越冬情况。【结果】广聚萤叶甲和豚草卷蛾的扩散能力强。释放1个月后,在释放区,广聚萤叶甲各虫态及豚草卷蛾虫瘿均被发现。整体上,随时间延长,广聚萤叶甲各虫态虫口密度先增后减,而豚草卷蛾虫瘿密度呈逐渐降低趋势。释放2个月后,在距释放区边缘10 km的豚草发生区,发现了广聚萤叶甲和豚草卷蛾,且成功建立了种群并顺利越冬。释放区豚草株高几乎没有增加,且叶片最终被取食精光,几乎全部死亡;扩散区豚草株高略有增加,最终近75%叶片被取食。【结论】广聚萤叶甲和豚草卷蛾可在永州成功建立种群并安全越冬,还能自行扩散,可持续控制野外豚草的发生。

Population dynamics of Ophraella communa and Epiblema strenuana and their control efficiency on Ambrosia artemisiifolia in Yongzhou City, Hunan Province, China

Aim] The common ragweed Ambrosia artemisiifolia is an important invasive weed, which seriously endangers agricultural production and human health. Ophraella communa (Coleoptera:Chrysomelidae) and Epiblema strenuana (Lepidoptera:Tortricidae) are two specific natural enemies of this plant. Study on the control effect of these two natural enemies and their population dynamics in Yongzhou will provide information towards effective utilization of these two natural enemies.Method] O. communa and E. strenuana were artificially released in a large area of common ragweed in Jiangyong County, Yongzhou City, Hunan Province. The population dynamics of these two natural enemies and their control efficiency on A. artemisiifolia in the released and expanded fields, and their wintering in the expanded fields were investigated.Result] All instars of O. communa and galls of E. strenuana were found in the released field one month after release. Overall, the population density of each instar O. communa increased first and then decreased, while the population density of E. strenuana was always low and decreased with time. O. communa and galls of E. strenuana were found on common ragweed 10 km from the edge of the released field after two months. Populations of these two natural enemies were successfully established and overwintered safely. In the release field, the height of common ragweed hardly increased, and the leaves were eventually eaten and almost all plants died. In the newly colonised fields, plant height increased slightly, and nearly 75% of the leaves were eaten.Conclusion] O. communa and E. strenuana successfully established in Yongzhou City and succesfully overwintered, then spread autonomously, and showed strong promise to control common ragweed.