Extracts from Field Margin Weeds Provide Economically Viable and Environmentally Benign Pest Control Compared to Synthetic Pesticides
Extracts from Field Margin Weeds Provide Economically Viable and Environmentally Benign Pest Control Compared to Synthetic Pesticides
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DOI：
10.1371/journal.pone.0143530
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发表时间：
2015-11-23
期刊：
影响因子：
3.7
通讯作者：
Belmain, Steven R.
中科院分区：
文献类型：
--
作者：
Mkenda, Prisila;Mwanauta, Regina;Belmain, Steven R.
几十年来，人们一直在研究具有杀虫特性的植物作为合成物的替代品，但大多数进展都是在实验室中取得的。因此，对杀虫植物的研究未能解决我们限制其吸收的知识空白。其中一些差距是对其在实地条件下的功效、经济可行性以及对有益生物体的影响的评估。由坦桑尼亚北部发现的四种丰富杂草（Tithonia diversifolia、Tephrosia vogelii、斑鸠菊和 Lippia javanica）提取的提取物可有效控制普通豆类植物（菜豆）上的主要害虫，其效果可与拟除虫菊酯合成物 Karate 相媲美。植物农药处理对天敌（瓢虫和蜘蛛）的影响显着降低。植物农药处理比合成农药更具成本效益，合成农药的边际回报率与未处理的对照没有什么不同，约为 4 美元/公顷，而植物农药处理的回报率约为 5.50 美元/公顷。化学分析证实，T. vogelii（鱼藤素鱼藤素）和 T. diversifolia（倍半萜内酯 tagitinin A）的水提取物中存在已知的杀虫化合物。苦杏仁有机提取物中也鉴定出了倍半萜内酯和皂苷斑鸠菊苷 C，但在水提取物中仅记录到皂苷，这与田间试验中使用的水提取物类似。杀虫植物能够更好地促进生态系统服务，同时有效管理害虫。采集和加工农田附近丰富植物的劳动力成本低于购买合成农药的成本。
Plants with pesticidal properties have been investigated for decades as alternatives to synthetics, but most progress has been shown in the laboratory. Consequently, research on pesticidal plants is failing to address gaps in our knowledge that constrain their uptake. Some of these gaps are their evaluation of their efficacy under field conditions, their economic viability and impact on beneficial organisms. Extracts made from four abundant weed species found in northern Tanzania, Tithonia diversifolia, Tephrosia vogelii, Vernonia amygdalina and Lippia javanica offered effective control of key pest species on common bean plants (Phaseolus vulgaris) that was comparable to the pyrethroid synthetic, Karate. The plant pesticide treatments had significantly lower effects on natural enemies (lady beetles and spiders). Plant pesticide treatments were more cost effective to use than the synthetic pesticide where the marginal rate of return for the synthetic was no different from the untreated control, around 4USD/ha, compared to a rate of return of around 5.50USD/ha for plant pesticide treatments. Chemical analysis confirmed the presence of known insecticidal compounds in water extracts of T. vogelii (the rotenoid deguelin) and T. diversifolia (the sesquiterpene lactone tagitinin A). Sesquiterpene lactones and the saponin vernonioside C were also identified in organic extracts of V. amygdalina but only the saponin was recorded in water extracts which are similar to those used in the field trial. Pesticidal plants were better able to facilitate ecosystem services whilst effectively managing pests. The labour costs of collecting and processing abundant plants near farm land were less than the cost of purchasing synthetic pesticides.