乔 岩, 董 杰, 王品舒, 岳 瑾, 张保常, 张金良, 袁志强, 杨建国*

1.北京市植物保护站, 北京 100029;2.北京市平谷区植保站, 北京 101205

三种生物源农药对桃树蚜虫的防治效果研究

乔 岩1, 董 杰1, 王品舒1, 岳 瑾1, 张保常2, 张金良1, 袁志强1, 杨建国1*

1.北京市植物保护站, 北京 100029;2.北京市平谷区植保站, 北京 101205

为筛选生产上防治桃树蚜虫的生物源农药，开展了1.5%除虫菊素水剂、0.3%苦参碱水剂和5%桉油精可溶液剂对桃树蚜虫的田间防效试验。结果表明，3种生物源农药中以0.3%苦参碱水剂防治效果最好，药后1 d防效为70.12%，药后7 d防效为91.96%，与对照药剂70% 吡虫啉水分散粒剂防效相当，具有较好的速效性和持效性。苦参碱对桃树安全，是防治桃蚜的理想药剂，生产上推荐使用浓度为1 000倍液。

生物源农药；桃蚜；防效

桃树蚜虫主要有桃蚜(Myzuspersicae) 、桃粉蚜(Hylalopterusamygdali) 和桃瘤蚜(Myzusmomonis)，是危害桃、杏、李的3种主要害虫，常混合发生危害。桃蚜被害叶皱缩卷曲，严重影响枝、叶的发育，其分泌物易生霉菌，传播病毒；桃粉蚜危害叶片、新梢和果实，污染果面，引起叶、梢干枯，削弱树势; 桃瘤蚜可使叶面纵卷，肿胀扭曲，叶肉增厚，最后干枯脱落。3种蚜虫世代多、繁殖量大、蔓延迅速、防治困难，是影响桃高产、稳产的重要限制因素，尤其是树龄大、管理粗放的桃园受害更重[1]。

常见防治桃树蚜虫的方法主要采取吡虫啉、抗蚜威、蚜虱净等农药进行化学防治，但污染环境，易导致农药残留，影响果实质量安全。由于长期使用化学药剂防治桃蚜，导致桃蚜对多种药剂产生了抗性，常用药剂的防效明显下降，防治变得越来越困难[2,3]。

生物源农药是从生物组织中提取的生物活性物质, 如苦参素、苦楝素和印楝素等, 其优势在于没有化学农药所表现的诸多副作用。寻找安全、高效、残效期长的生物源农药替代化学农药，已成为绿色、有机大桃生产急需破解的生产难题[4～5]。

为此，我们开展了3种生物源农药对桃蚜的田间药效试验，以期取得理想效果，为大桃生产中存在的蚜虫问题，提供一种安全、有效的防治手段。

1 材料和方法

1.1 供试材料

供试药剂为1.5%除虫菊素水乳剂，由云南南宝植化有限责任公司生产，试验药液喷洒浓度为600倍液；0.3%苦参碱水剂由北京中捷四方生物科技有限公司生产， 试验药液喷洒浓度为1 000倍液；5%桉油精可溶液剂购自北京亚戈农生物药业有限公司，试验药液喷洒浓度为1 000倍液；对照药剂70%吡虫啉水分散粒剂购自陕西上格之路生物科学有限公司，试验药液喷洒浓度为2 000倍液。

1.2 试验方法

试验地选择在平谷区夏各庄镇陈太务村桃园中进行，树龄12年。果园地势平坦，光照条件好，长势均匀，肥水管理水平一致。桃树株行距4 m×5 m。试验设5个处理，分别为1.5%除虫菊素水乳剂600倍液，0.3%苦参碱水剂1 000倍液，5%桉油精可溶液剂1 000倍液，70%吡虫啉水分散粒剂2 000倍液，空白对照喷清水。施药时间为2014年4月3日，使用喷杆式喷雾器，喷雾均匀、彻底，达到整株淋洗状态。2株树为1个小区，重复3次，随机排列。

1.3 调查时间和方法

喷药前和喷药后第1 d、3 d和7 d调查，共调查4次。调查小区内2株树，每株在东南西北中5个方位各标记一个有虫嫩梢，每梢自顶向下调查5片叶(包括枝条)的活虫数。药效计算方法按下式计算，对照小区也按此法调查。

虫口减退率(%) =[(药前虫口密度-药后虫口密度)÷药前虫口密度]×100%

防治效果(%)=[(处理虫口减退率-对照虫口减退率)÷(1-对照虫口减退率)]×100%。

2 结果与分析

2.1 对桃蚜的防治效果

试验结果表明(表1)，施药后1 d，0.3%苦参碱水剂防治效果即达到70.12%,与对照药剂70%吡虫啉水分散粒剂防效相当，表现出较好的速效性。1.5%除虫菊素水剂和5%桉油精可溶液剂防效分别为26.45%和19.63%，显著低于对照药剂70%吡虫啉水分散粒剂2 000倍液。施药后4 d，0.3%苦参碱水剂1 000倍液防治效果为69.7%，与药后1 d相比，防效略有下降，与对照药剂70%吡虫啉水分散粒剂防效相当。1.5%除虫菊素水剂和5%桉油精可溶液剂防效分别为31.28%、36.78%，与施药后1 d相比，防效均显著提高，仍显著低于对照药剂70%吡虫啉水分散粒剂2 000倍液。药后7 d，各药剂处理防治效果均继续增加，0.3%苦参碱水剂防治效果达到91.96%,与对照药剂70%吡虫啉水分散粒剂防效相当。1.5%除虫菊素水剂和5%桉油精可溶液剂防效分别为65.89%和71.37%，显著低于对照药剂70%吡虫啉水分散粒剂2 000倍液。不同药剂对桃蚜的防治效果差异显著。各药剂随施药后随时间增加防治效果提高，药后7 d达到最好防治效果。

表1 4种药剂防治桃树蚜虫效果

注:同列数据后不同小写字母代表差异显著(P<0.05)。

2.2 安全性

通过目测各处理药剂对作物的安全性，施药后1～7 d均未发现可观察到的明显药害症状，果实未见异常或畸形果，可见3 种生物药剂防治桃蚜未对果树及果实产生明显的不良影响，说明以上药剂对大桃作物安全。

3 讨论

田间试验结果表明, 0.3%苦参碱水剂1 000倍液防治蚜虫的效果非常理想, 药后第7 d, 防效可达91.96%, 说明0.3%苦参碱水剂持效期长, 是防治蚜虫的理想药剂。从经济有效方面综合考虑, 0.3%苦参碱水剂防治蚜虫的田间使用剂量以1 000倍液为宜。

1.5%除虫菊素水剂和5%桉油精可溶液剂药后7 d防效分别达到65.89%和71.37%，与对照药剂吡虫啉相比防效差异明显，对桃蚜的防治效果不甚理想。有研究表明，1.5%除虫菊素水乳剂用于蔬菜蚜虫的防治时，接触到药剂的部位效果较好，可能是由于该药剂内吸作用和渗透作用较差[6]。因此，桃园使用除虫菊素水乳剂时，应注意均匀喷雾。5%桉油精可溶液剂目前用于防治林业害虫较多，对槐蚜的防治效果一般[7]，对桃蚜的防治效果及使用技术还有待进一步研究。

2011年，宫亚军等[8]研究发现，在北京地区，蔬菜上桃蚜对吡虫啉仍具有很高的敏感性，北京地区普遍使用吡虫啉做为防治桃蚜的首选药物。本研究中，桃树上的蚜虫对吡虫啉比较敏感，但是随着使用时间的延长和用药次数的增加，抗性也会发生。可以采取轮换用药或者将不同作用机制的农药科学合理地复配混用，增加药效，减少用药频次，省时省工，降低成本，延缓抗药性产生[9]。根据本试验的结果，苦参碱可以作为吡虫啉的替代药剂。

0.3%苦参碱水剂高效低毒, 持效期长, 防治蚜虫效果好, 具有对人畜、环境、天敌等安全和果品无农药残留、无三致(致癌、致畸、致突变)、无药害、不易产生抗性等优点, 符合绿色果品生产的要求[10]。因此, 建议在今后生产中大力推广应用0.3%苦参碱水剂防治蚜虫。

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[2] 陶 晡，康占海，李 星. 25%噻虫嗪水分散粒剂防治桃蚜试验[J]. 山西果树，2014, 4：53-55.

[3] 李定旭. 两种新型药剂防治苹果及桃树蚜虫药效试验[J]. 中国果树，2002, 11：33-35.

[4] 苏明申, 叶正文, 李胜源，等. 生物有机农药毒杀对桃树蚜虫的试验[J]. 中国果树，2008, 3：74.

[5] 杜肇南， 刘长禄. 一种新型植物源杀虫剂的研制及桃树蚜虫防治试验[J]. 中国果菜，2012, 10：20-21.

[6] 刘艳芝，马井玉，徐祥文，等. 不同浓度天然除虫菊素水乳剂防治蔬菜蚜虫田间药效试验[J]. 长江蔬菜，2012, 12：70-71.

[7] 常承秀，朱惠英，张永强，等.8种药剂防治槐蚜药效试验[J]. 森林保护，2013, 7：36-38.

[8] 宫亚军，王泽华，石宝才, 等. 北京地区不同桃蚜种群的抗药性研究[J]. 植物保护，2011, 44(21)：43-178.

[9] 刘雨晴，范 毅，于立芹, 等. 天然苦皮藤素和天然除虫菊素混配对三种蚜虫的毒力及田间防效[J]. 植物保护，2014, 40(2)：175-178.

[10] 窦立峰，王建玉，柳富华. 0.3%复方苦参碱水剂防治蚜虫药效试验[J]. 山西果树，2009, 129：11-12.

·Nature系列期刊导读·

科学家通过增加靶点范围来扩大CRISPR-Cas9技术的可用性

近日，研究者们发现一种用来改善基因编辑工具CRISPR-Cas9 RNA引导核酸酶可用性和精确性的方法或许可以应用于其他细菌的Cas9酶中，他们发现了一种金黄色葡萄球菌Cas9酶类-SaCas9酶类突变体，该突变体可以识别更广范围的核苷酸序列，这或许可以帮助CRISPR-Cas9技术对此前无法靶向作用的基因组位点进行靶向作用。该系统在不需要SaCas9的精确结构的前提下就可以对PAM特异性进行工程性地修饰改变。研究者表示，如今我们利用定向的进化方法就可以用来修饰酶类SaCas9的PAM序列特异性，这就扩大了Cas9酶类可获取靶向作用的基因位点的数量，精确靶向作用位点的能力对于研究人员非常关键。

论文链接: Benjamin P K,etal.. Broadening the targeting range ofStaphylococcusaureusCRISPR-Cas9 by modifying PAM recognition. Nature Biotechnology,2015,doi:10.1038/nbt.3404.

Abstract: CRISPR-Cas9 nucleases target specific DNA sequences using a guide RNA but also require recognition of a protospacer adjacent motif (PAM) by the Cas9 protein. Although longer PAMs can potentially improve the specificity of genome editing, they limit the range of sequences that Cas9 orthologs can target. One potential strategy to relieve this restriction is to relax the PAM recognition specificity of Cas9. Here we used molecular evolution to modify the NNGRRT PAM ofStaphylococcusaureusCas9 (SaCas9). One variant we identified, referred to as KKH SaCas9, showed robust genome editing activities at endogenous human target sites with NNNRRT PAMs, thereby increasing SaCas9 targeting range by two - to fourfold. Using GUIDE-seq, we show that wild-type and KKH SaCas9 induce comparable numbers of off-target effects in human cells. Our strategy for evolving PAM specificity does not require structural information and therefore should be applicable to a wide range of Cas9 orthologs.

我国科学家开发出新技术可对miRNA肉眼计数

东南大学顾宁教授课题组利用T7噬菌体的可修饰性以及快速生长繁殖的特性，采用生物分子操作技术与纳米合成修饰技术，制备了一种特殊的探针，实现了一个肉眼直接计数目标的可寻址(如，一个绿色噬菌斑对应一个A目标，一个红色噬菌斑对应一个B目标)的绝对定量检测策略。该策略通过对合成的microRNA纯净样品以及真实样本(细胞、血清及肿瘤组织)中microRNA的肉眼计数，证明了其高灵敏度、可寻址及肉眼直接计数的特性。该检测策略具有检测对象的通用性。对纳米粒子上的配体进行适当替换，不仅可检测核酸类分子，还可检测蛋白类分子，以及病毒等病原体。若将此策略进一步发展为自动化的检测系统，将可实现更快速的定量分析，具有良好的应用前景。

论文链接: Zhou X,etal.. Phage-mediated counting by the naked eye of miRNA molecules at attomolar concentrations in a Petri dish. Nature Materials, 2015, doi:10.1038/nmat4377.

Abstract: The ability to count biomolecules such as cancer-biomarker miRNAs with the naked eye is seemingly impossible in molecular diagnostics. Here, we show an ultrasensitive naked-eye-counting strategy for quantifying miRNAs by employing T7 phage—a bacteria-specific virus nanoparticle—as a surrogate. The phage is genetically engineered to become fluorescent and capable of binding a miRNA-capturing gold nanoparticle (GNP) in a one-to-one manner. Target miRNAs crosslink the resultant phage-GNP couple and miRNA-capturing magnetic microparticles, forming a sandwich complex containing equimolar phage and miRNA. The phage is then released from the complex and developed into one macroscopic fluorescent plaque in a Petri dish by plating it in a host bacterial medium. Counting the plaques by the naked eye enables the quantification of miRNAs with detection limits of ～3 and ～5 aM for single-target and two-target miRNAs, respectively. This approach offers ultrasensitive and convenient quantification of disease biomarkers by the naked eye.

新技术以可让肽类药物更加持久

近日，来自太平洋大学的科学家通过研究开发了一种新方法，可以明显延长机体肽类的生命，该研究或为后期开发新型肽类药物来治疗癌症及其他疾病提供思路。蛋白肽类可以被工程化操作来治疗一系列疾病，包括癌症和糖尿病等，这些小型的氨基酸链具有非常大的潜力和选择性，而且相比大分子要更加安全一些，但肽类较短的寿命迫使科学家们不得不使用大剂量且频繁给予患者来增加作用效果。该文中研究者利用新技术可以使得肽类寿命延长，这就可以降低肽类药物的使用频率，从而帮助患者节约药物成本且降低患者的依从性。该项研究对于改善人类健康又迈进了一步，文章中采用的方法具有巨大的应用潜力，其不光可以帮助治疗疾病，还可以增强对患者机体的成像及诊断。

论文链接: Sravan C P,etal.. A biomimetic approach for enhancing the in vivo half-life of peptides. Nature Chemical Biology,2015,doi:10.1038/nchembio.1907.

Abstract: The tremendous therapeutic potential of peptides has not yet been realized, mainly owing to their short in vivo half-life. Although conjugation to macromolecules has been a mainstay approach for enhancing protein half-life, the steric hindrance of macromolecules often harms the binding of peptides to target receptors, compromising the in vivo efficacy. Here we report a new strategy for enhancing the in vivo half-life of peptides without compromising their potency. Our approach involves endowing peptides with a small molecule that binds reversibly to the serum protein transthyretin. Although there are a few molecules that bind albumin reversibly, we are unaware of designed small molecules that reversibly bind other serum proteins and are used for half-life extension in vivo. We show here that our strategy was effective in enhancing the half-life of an agonist for GnRH receptor while maintaining its binding affinity, which was translated into superior in vivo efficacy.

微生物合作的新机制被揭示

海洋沉积物中甲烷的厌氧氧化，是由甲烷氧化古菌和能产生硫酸盐的细菌共同完成的一个协作过程。人们曾认为，一种可溶性代谢物在合作的微生物之间的交换是必不可少的，但在Victoria及同事最近的研究结果否定了这一假设。他们在单细胞层面上，对来自西北太平洋中一个活动甲烷渗出泉取样的沉积物制备的微生物混合体中的生物合成活性做了相关研究。他们发现，细胞活动是独立于互养伙伴之间的距离的，这与涉及中间体短距离扩散的一个模型是不一致的。实际上，古菌与细菌之间的直接电子转移，才是它们相互作用的核心机制。

论文链接: Mcglynn S E,etal.. Single cell activity reveals direct electron transfer in methanotrophic consortia. Nature, 2015,doi: 10.1038/nature15512.

Abstract: Multicellular assemblages of microorganisms are ubiquitous in nature, and the proximity afforded by aggregation is thought to permit intercellular metabolic coupling that can accommodate otherwise unfavourable reactions. Consortia of methane-oxidizing archaea and sulphate-reducing bacteria are a well-known environmental example of microbial co-aggregation; however, the coupling mechanisms between these paired organisms is not well understood, despite the attention given them because of the global significance of anaerobic methane oxidation. Here we examined the influence of interspecies spatial positioning as it relates to biosynthetic activity within structurally diverse uncultured methane-oxidizing consortia by measuring stable isotope incorporation for individual archaeal and bacterial cells to constrain their potential metabolic interactions. In contrast to conventional models of syntrophy based on the passage of molecular intermediates, cellular activities were found to be independent of both species intermixing and distance between syntrophic partners within consortia. A generalized model of electric conductivity between co-associated archaea and bacteria best fit the empirical data. Combined with the detection of large multi-haem cytochromes in the genomes of methanotrophic archaea and the demonstration of redox-dependent staining of the matrix between cells in consortia, these results provide evidence for syntrophic coupling through direct electron transfer.

生物多样性丧失威胁生态系统稳定性

近日，研究者们将来自46个实验的数据相结合发现，生物多样性会提高一个生态系统对极端气候事件的抵抗力。只有少量物种的地块，在极端气候事件期间生产力下降了50%，而这种影响随着物种数量的增加会被减半。然而，生物多样性对生态系统弹性没有明显影响，低生物多样处理和高生物多样性处理，在一年内，都能够从极端气候事件中恢复过来。

论文链接: Nico E,etal.. Biodiversity increases the resistance of ecosystem productivity to climate extremes. Nature, 2015, doi: 10.1038/nature15374.

Abstract: It remains unclear whether biodiversity buffers ecosystems against climate extremes, which are becoming increasingly frequent worldwide. Early results suggested that the ecosystem productivity of diverse grassland plant communities was more resistant, changing less during drought, and more resilient, recovering more quickly after drought, than that of depauperate communities. However, subsequent experimental tests produced mixed results. Here we use data from 46 experiments that manipulated grassland plant diversity to test whether biodiversity provides resistance during and resilience after climate events. We show that biodiversity increased ecosystem resistance for a broad range of climate events, including wet or dry, moderate or extreme, and brief or prolonged events. Across all studies and climate events, the productivity of low-diversity communities with one or two species changed by approximately 50% during climate events, wheras that of high-diversity communities with 16～32 species was more resistant, changing by only approximately 25%. By a year after each climate event, ecosystem productivity had often fully recovered, or overshot, normal levels of productivity in both high-and low-diversity communities, leading to no detectable dependence of ecosystem resilience on biodiversity. Our results suggest that biodiversity mainly stabilizes ecosystem productivity, and productivity-dependent ecosystem services, by increasing resistance to climate events. Anthropogenic environmental changes that drive biodiversity loss thus seem likely to decrease ecosystem stability, and restoration of biodiversity to increase it, mainly by changing the resistance of ecosystem productivity to climate events.

青蒿素类过氧桥键的生物合成机制被解析

青蒿素的生物活性与过氧键密不可分，但是催化青蒿酸形成青蒿素的环内过氧键合酶却一直没有找到，成为一道世界难题。科学家们最近从几株曲霉和青霉菌种中分离出具有抗感染等多种生物活性的萜类吲哚生物碱真菌毒素Verruculogen。文章首次报道了FtmOx1的晶体结构，以及FtmOx1分别与a-酮戊二酸和底物fumitremorgen B的共晶体结构，并通过详尽的酶学实验结果验证了FtmOx1的功能。快速反应动力学和冷冻淬火电子自旋光谱实验结果证实了FtmOx1反应中存在自由基中间体。阐明这一特别的环内过氧桥键的生物合成新机制为发现催化青蒿酸形成青蒿素的环内过氧键合酶向前迈进了一大步。进一步研究其酶学机制，将为含有过氧桥键的萜类吲哚生物碱的广泛应用奠定科学和应用基础。

论文链接: Yan W P,etal.. Endoperoxide formation by an α-ketoglutarate-dependent mononuclear non-haem iron enzyme. Nature, 2015, doi:10.1038/nature15519.

Abstract: Many peroxy-containing secondary metabolites have been isolated and shown to provide beneficial effects to human health. Yet, the mechanisms of most endoperoxide biosyntheses are not well understood. Although endoperoxides have been suggested as key reaction intermediates in several cases, the only well-characterized endoperoxide biosynthetic enzyme is prostaglandin H synthase, a haem-containing enzyme. Fumitremorgin B endoperoxidase (FtmOx1) from Aspergillus fumigatus is the first reported α-ketoglutarate-dependent mononuclear non-haem iron enzyme that can catalyse an endoperoxide formation reaction. To elucidate the mechanistic details for this unique chemical transformation, we report the X-ray crystal structures of FtmOx1 and the binary complexes it forms with either the co-substrate (α-ketoglutarate) or the substrate (fumitremorgin B). Uniquely, after α-ketoglutarate has bound to the mononuclear iron centre in a bidentate fashion, the remaining open site for oxygen binding and activation is shielded from the substrate or the solvent by a tyrosine residue (Y224). Upon replacing Y224 with alanine or phenylalanine, the FtmOx1 catalysis diverts from endoperoxide formation to the more commonly observed hydroxylation. Subsequent characterizations by a combination of stopped-flow optical absorption spectroscopy and freeze-quench electron paramagnetic resonance spectroscopy support the presence of transient radical species in FtmOx1 catalysis. Our results help to unravel the novel mechanism for this endoperoxide formation reaction.

Control Effects of Three Biogenic Pesticides on Controlling Peach Aphids

QIAO Yan1, DONG Jie1, WANG Pin-shu1,YUE Jin1, ZHANG Bao-chang2, ZHANG Jin-liang2, YUAN Zhi-qiang1, YANG Jian-guo1*

1.BeijingPlantProtectionStation,Beijing100029,China;2.BeijingPingguDistrictPlantProtectionStation,Beijing101205,China

To screen biogenic pesticides in controlling aphids on peach tree, the field test was carried out using 1.5% pyrethrin aqueous solution (AS), 0.3% matrine AS and 5% eucalyptole soluble concentrate against aphids in the field. The results indicated that of the three biogenic pesticides, 0.3% matrine AS was the most effective. The control efficiency could reach 70.12% on the first day and 91.96% on the 7th day respectively after spraying. Comparing with 70% imidacloprid water dispersible granule, the control effects of 0.5% matrine AS were not significantly different. Matrine AS was well quick-acting and persistance on the control of aphids. The matrine AS was safe to peach tree, and was ideal pesticide to control aphids. The 1 000 dilution of 0.3% matrine AS was suggested to be applied in the fields.

biogenic pesticides; peach aphids; control efficiency

2015-09-08; 接受日期：2015-10-28

农作物病虫鼠害疫情监测与防治项目资助。

乔岩，高级农艺师，研究方向为粮经作物病虫害防治。E-mail：qy0914@126.com。*通信作者：杨建国，推广研究员，主要从事粮食、经济作物病虫害绿色防控技术研究及示范推广工作。E-mail：yangjguo@263.net

10.3969/j.issn.2095-2341.2015.06.12