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【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129.5cm),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。
【Background】 In order to assess the potential of control of ragweed after the widespread release of A. rhamnoides from the broad-leaved area of Larvardia chinensis, in 2007 and the end of May 2008 respectively, The field release test. 【Method】 The plant height and survival rate of ragweed were investigated after the natural enemies were released. Finally, their biomass and seed amount were measured. 【Result】 The results showed that the plant height (61.4 and 99.0 cm) in the release area was significantly shorter than that in the control area (121.8 and 129.5 cm) after release for 86 and 120 days, respectively. The shoot dry weight in the release area was significantly smaller than that in the control area, There was no significant difference between the dry weight and the control area; the survival rate of the released area was only 7.3% and 0 respectively. After releasing for 12 days, the plant height and survival rate of released ragweed did not differ significantly from that of the control plots after release for 12 days. However, after 28, 44 and 57 days of release, the plant height of the released area was significantly smaller than that of the control, The dry weight of aboveground stems was also significantly lower than that of the control area. The survival rates of ragweed in the release area were 76.5%, 16.5% and 0%, respectively. The survival rates of ragweed in the two control plots during the survey period were both 100%, and that of ragweed in the release area was completely loss of breeding capacity. CONCLUSION AND SIGNIFICANCE In Hunan, late May or early June, Unicornia macrophylla and Ragweed larvae were released at a density of about 6 per 10 plants to control ragweed effectively. The results provided the basis for the popularization and application of ragweed biological control technology.