豚草生物防治技术在湖南汨罗的应用及其控制效果

【背景】为评价广聚萤叶甲和豚草卷蛾在豚草发生区大面积释放后对豚草的控制潜力，于2007年和2008年5月底分别在湖南省汨罗大荆和智峰进行了野外释放试验。【方法】释放天敌后，调查豚草的株高、存活率，最后测量其生物量和种子量。【结果】在大荆释放区释放86和120d后，释放区植株高度（61．4和99．0cm）均显著矮于对照区（121．8和129．5em），释放区植株地上茎干重显著小于对照区，但根系干重与对照区无显著差异；释放区植株存活率分别仅为7．3％和0。在智峰释放区，释放12d后，释放区豚草株高和存活率与对照区均无显著差异；但在释放28、44、57d后，释放区株高均显著小于对照区，植株根系和地上茎干重亦显著小于对照区；释放区豚草存活率分别为76．5％、16．5％和0。上述两地，对照区豚草在调查期内的存活率均为100％，释放区的豚草则完全丧失繁殖能力，种子量为0。【结论与意义】在湖南，5月底或6月初，广聚萤叶甲和豚草卷蛾以约每10株6头的密度联合释放，可有效控制豚草。本结果为豚草生物防治技术推广与应用提供了依据。

A field trial of biological, control of Ambrosia artemisiifolia with two herbivorous insects in Miluo, Hunan Province, China

Background ] To estimate the control potential of Ophraella communa （ Coleoptera： Chrysomelidae） and Epiblema strenu- ana （Lepidoptera： Tortricidae） on Ambrosia artemisiifolia after mass-releasing in the areas invaded by A. artemisiifolia, they were jointly released in the field at the towns of Dajing and Zhifeng, Miluo city, Hunan Province at the end of May, 2007 and 2008, re- spectively. Method] The plant height and survival rate of A. artemisiifolia were surveyed after releas!ng the two insects, and the plant and seed biomasses were measured at the end of survey. Result] At Dajing town, 86 and 120 days after releasing, A. artemis- iifolia plants were significantly shorter in the release region （61.4 cm and 99.0 cm） than in the control region （ 121.8 cm and 129.5 cm, respectively）. The dry mass of the above-ground plants was significantly lower in the release than in the control region, but no difference in root dry biomass of was observed between the two regions. Survival rate ofA. artemisiifolia were only 7.3% after 86 days, and all plants died by day 120 in the release region. At Zhifeng town, the plant height and survival rate ofA. artemisiifolia showed no variation between the release and con.trol regions 12 days after release. However, 28, 44 and 57 days after release, the plant height of A. artemisiifolia were significantly shorter in the release than in the control region, and root dry mass and above- ground were also significantly lower in the release than in the control region. Survival rate in the release region of A. artemisiifolia were 63.5%, 16.5% 28 and 44 days after release, respectively, and by day 57, no plant was left alive. At the two above places,the survival rate of A. artemisiifolia maintained 100% in the control regions during our survey, and all A. artemisiifolia plants lost their fecundities completely, thus the seed biomasses were 0 in the release region. Conclusion and significance ] In Hunan Prov- ince, A. artemisiifolia can be suppressed effectively when 0. communa and E. strenuana are jointly released in the areas invaded by A. artemisiifolia at the end of May and early June.