替代物种与除草剂对紫茎泽兰的防效及其互作效应

目的]研究替代物种与选择性除草剂，以实现对紫茎泽兰安全、高效和绿色的防控。方法]采用植物间竞争试验法测定替代物种（高丹草、非洲狼尾草和黑麦草）和除草剂对紫茎泽兰的防效及其互作效应。结果]高丹草、非洲狼尾草和黑麦草的竞争力依次强于紫茎泽兰。随着3种替代物种密度比例增加，紫茎泽兰的株高、分枝、根冠比、叶面积比均受到显著抑制，当替代物种与紫茎泽兰密度比为5∶1时，高丹草、非洲狼尾草和黑麦草对紫茎泽兰的替代控制效果分别为55.1%、46.9%和40.3%。除草剂氨氯吡啶酸、三氯吡氧乙酸、氯氟吡氧乙酸和二氯吡啶酸的毒力测定表明，二氯吡啶酸相对最高，LC₉₀为902.1 g·hm^-2，但三氯吡氧乙酸对替代物种的安全性相对最好，对高丹草、非洲狼尾草和黑麦草选择性指数分别为3.75、2.79和2.67。高丹草和非洲狼尾草与紫茎泽兰种植密度比例为3∶1时，结合二氯吡啶酸和三氯吡氧乙酸，非洲狼尾草和二氯吡啶酸结合表现拮抗作用，与三氯吡氧乙酸结合表现加成作用；高丹草和二氯吡啶酸结合表现加成作用，与三氯吡氧乙酸结合表现增效作用，在同等取得90%防效的情况下，可减少三氯吡氧乙酸用量20.0%~35.0%（即210.0~370.0 g·hm^-2）。结论]合理的替代物种结合除草剂应用可实现互作增效，可作为紫茎泽兰综合防控的重要措施。

Control effects of alternative species and herbicides on Ageratina adenophora and their interaction

Aim] To explore the ecological management of Ageratina adenophora through combinations of alternative species and herbicide applications.Method] The control effects of competitive species (such as Sorghum bicolor×S. sudanense, Pennisetum squamulatum, and Lolium perenne) and herbicides (such as aminopyralid, triclopyr, fluroxypyr, and clopyralid) on A. adenophora and their interaction effects were determined using competition experiments. Three ratios of these competitive species and the invasive species were utilized (1:1, 3:1, 5:1) in a complete randomized design with 4 replicates.Result] The competitive balance index of S. bicolor×S. sudanense, P. squamulatum and L. perenne was greater than zero for most ratios, except for the 1:1 ratio of L. perenne and A. adenophora. Plant height, branch, root shoot ratio, and leaf area ratio of A. adenophora were significantly reduced with increasing proportions of the three alternative species. The replacement control effects of S. bicolor×S. sudanense, P. squamulatum and L. perenne on A. adenophora were 55.1%, 46.9% and 40.3% at the highest ratio of three alternative species:A. adenophora (5:1), respectively. Toxicity test showed that among the four herbicides analyzed, the clopyralid had the highest bioactivity (LC₉₀=902.1 g·hm^-2) in A. adenophora. However, triclopyr had higher safety to three alternative species, with the selectivity index of 3.75, 2.79 and 2.67 to S. bicolor×S. sudanense, P. squamulatum, and L. perenne, respectively. For a ratio of S. bicolor×S. sudanense and P. squamulatum to A. adenophora of 3:1 plus triclopyr and clopyralid application, P. squamulatum showed an antagonistic effect with clopyralid and an additive effect with triclopyr. S. bicolor×S. sudanense had an additive effect with clopyralid and synergistic effect with triclopyr, respectively. Compared to triclopyr application alone over 90% of the control rate, the use dosage of triclopyr was reduced by 20.0%-35.0% (i.e., 210.0-370.0 g·hm^-2) when S. bicolor×S. sudanense and triclopyr combination.Conclusion] These results suggest that alternative species competition and herbicide combinations can achieve a more secure, sustainable, and long-term control of A. adenophora.