农业措施在害虫种群无公害控制中的作用

作物抗性品种、布局、耕作制度以及栽培管理等农业措施可以有效地调节害虫的种群数量,合理和综合运用这些措施,可以实现害虫生态调控的目的,从而为农作物的无公害生产提供新的植保技术。本文从农业措施在害虫控制中的直接作用、对天敌昆虫的影响等方面进行了综述,同时对利用农业措施控制害虫的几个问题进行了探讨,以期为合理利用和正确评价农业措施控制害虫提供参考。     

Pharmacological approaches to nitric oxide signalling during neural development of locusts and other model insects

A novel aspect of cellular signalling during the formation of the nervous system is the involvement of the messenger molecule nitric oxide (NO), which has been discovered in the mammalian vascular system as mediator of smooth muscle relaxation. NO is a membrane-permeant molecule, which activates soluble guanylyl cyclase (sGC) and leads to the formation of cyclic GMP (cGMP) in target cells. The analysis of specific cell types in model insects such as Locusta, Schistocerca, Acheta, Manduca, and Drosophila shows that the NO/cGMP pathway is required for the stabilization of photoreceptor growth cones at the start of synaptic assembly in the optic lobe, for regulation of cell proliferation, and for correct outgrowth of pioneer neurons. Inhibition of the NOS and sGC enzymes combined with rescue experiments show that NO, and potentially also another atypical messenger, carbon monoxide (CO), orchestrate cell migration of enteric neurons. Cultured insect embryos are accessible model systems in which the molecular pathways linking cytoskeletal rearrangement to directed cell movements can be analyzed in natural settings. Based on the results obtained from the insect models, I discuss current evidence for NO and cGMP as essential signalling molecules for the development of vertebrate brains.     

Phylogeography of the pine processionary moth Thaumetopoea wilkinsoni in the Near East

Phylogeographic structure of the eastern pine processionary moth Thaumetopoea wilkinsoni was explored in this study by means of nested clade phylogeographic analyses of COI and COII sequences of mitochondrial DNA and Bayesian estimates of divergence times. Intraspecific relationships were inferred and hypotheses tested to understand historical spread patterns and spatial distribution of genetic variation. Analyses revealed that all T. wilkinsoni sequences were structured in three clades, which were associated with two major biogeographic events, the colonization of the island of Cyprus and the separation of southwestern and southeastern Anatolia during the Pleistocene. Genetic variation in populations of T. wilkinsoni was also investigated using amplified fragment length polymorphisms and four microsatellite loci. Contrasting nuclear with mitochondrial data revealed recurrent gene flow between Cyprus and the mainland, related to the long-distance male dispersal. In addition, a reduction in genetic variability was observed at both mitochondrial and nuclear markers at the expanding boundary of the range, consistent with a recent origin of these populations, founded by few individuals expanding from nearby localities. In contrast, several populations fixed for one single mitochondrial haplotype showed no reduction in nuclear variability, a pattern that can be explained by recurrent male gene flow or selective sweeps at the mitochondrial level. The use of both mitochondrial and nuclear markers was essential in understanding the spread patterns and the population genetic structure of T. wilkinsoni, and is recommended to study colonizing species characterized by sex-biased dispersal.     

稻田生态系统多个物种共存对病虫草害的控制

建立多个物种共存的农作模式、利用物种多样性控制有害生物是农业可持续发展的重要途径.本文综述了国内外稻田物种多样性利用模式的研究进展,论述了稻田多个物种共存对水稻病、虫、草的控制效果及作用机理.稻田系统多个物种共存模式如稻田养鱼模式、稻田养鸭模式、稻-萍-鱼或稻-萍-鸭模式等,对水稻纹枯病、稻飞虱、稻纵卷叶螟和杂草有显著的控制作用;稻田系统多个物种共存的另一类模式如水稻品种多样性混合种植、稻-茭白间作和稻-湿生作物间作等,可明显降低稻瘟病等病害的发生与流行.稻田多个物种共存模式对病虫草控制的效果和机理研究仍需要从作物、分子生物学和化学生态等方面做进一步的研究探讨.     

Nanoparticle-mediated double-stranded RNA delivery system: A promising approach for sustainable pest management

RNA interference (RNAi) targeting lethal genes in insects has great potential for sustainable crop protection. Compared with traditional double-stranded (ds)RNA delivery systems, nanoparticles such as chitosan, liposomes, and cationic dendrimers offer advantages in delivering dsRNA/small interfering (si)RNA to improve RNAi efficiency, thus promoting the development and practice of RNAi-based pest management strategies. Here, we illustrate the limitations of traditional dsRNA delivery systems, reveal the mechanism of nanoparticle-mediated RNAi, summarize the recent progress and successful applications of nanoparticle-mediated RNAi in pest management, and finally address the prospects of nanoparticle-based RNA pesticides.     

豆野螟的生物防治研究进展与展望

豆野螟Maruca vitrata是豇豆等豆类作物的世界性重要害虫,常年在亚热带地区严重发生,防控难度很大。传统的化学防治方法难以对其进行长久且有效的控制,因而造成害虫抗药性增强、超范围使用化学农药等诸多不良现象,严重威胁人民群众身体健康与生态安全。而生物防治作为减少化学农药用量与残留的关键技术之一,在当前我国绿色农业高速发展期更应引起研究人员的高度重视。因此,本文围绕豆野螟生物防治的研究现状与进展,分别从昆虫性信息素、天敌昆虫资源、昆虫病原物、植物源农药等4个方面进行了概述,并深入探讨了我国豆野螟生物防治领域的研究前景与方向,为豆野螟绿色防控体系的全方位建设提供参考,助力我国绿色农业高质量发展。     

层次分析法在上海市农田有害生物治理中的应用

以上海市农业示范区(松江区)农药用量减少优化为例,在对其稻田农药用量现状进行调查分析的基础上,运用层次分析法的基本原理和数学模型进行了农药用量对策研究,建立了综合效益和综合代价的层次分析结构模型,将综合效益分为经济、社会、生态效益3个元素,综合代价分为经济、社会、生态代价3个元素。建立了判断矩阵,并作一致性检验,求出相应的权重;提出代价效益比RCP概念(综合代价与综合效益的比),对稻田农药用量对策进行排序,并依此作为衡量稻田农药用量的参考因子。根据分析结果,认为采用杀虫灯和施用化学农药5次(有效成分为2.23kg.hm-2)”相结合,是上海市水直播稻田有害生物的最佳防治策略。     

我国害鼠不育控制研究进展

害鼠给人类带来巨大的经济损失,导致严重的生态问题。人们采用各种方法防治鼠害,其中不育控制是一种新的方法。不育控制即通过某种手段使雄性或和雌性绝育,或阻碍胚胎着床,甚至阻断幼体生长,以降低生育率。不育控制的概念最早在20世纪60年代提出,近年来,我国在利用不育技术控制害鼠方面做了大量研究,总结了国内该领域研究的部分结果。在实验室测试了多种不育剂。被测试的不育剂对相应的鼠类几乎都有不育作用;一些不育剂会影响鼠类的行为,这会减弱竞争性繁殖干扰的作用;一些不育剂在达到一定剂量后有致死作用,不育和灭杀的双重作用会产生更好的控制效果;还观察到不育个体的复孕现象,这会减弱控制效果;关于不育剂安全性的研究发现更昔洛韦和M001雄性不育灭鼠剂对家鸽没有任何毒性作用。大量野外实验证实不育剂对害鼠大都有较好的控制效果,实际控制中,控制面积不宜太小。利用数学模型所作的理论分析表明不育控制有不比灭杀控制差的效果;在决定种群是否灭绝上,不育率、灭杀率、选择性收获率等的作用是相同的。根据研究的实际情况,本文提出了一些今后研究中应注意的问题。无论在实验室还是野外,除了种群动态外,还要记录更详细的数据,以期对不育控制有更详细的了解。要加大不育剂对非靶向动物和环境影响的研究。在不育控制这种干扰下,害鼠种群的变化必然导致与其相关的种群也作出相应的变化,这一方面的研究需要进行。每种控制方式都有自己的特点,多种控制方法联合使用会达到更理想的效果。竞争性繁殖干扰现象是存在的,它使种群规模更小,在数学模型中,应体现出这一因素。     

高CO2浓度和固氮菌对斜纹夜蛾幼虫食物利用效率的影响

"补偿取食"假说认为CO2浓度升高后植食性昆虫会增大取食量以弥补植物组织中氮素营养的不足。但实证研究并非都支持该假说。用人工智能气候箱设置CO2浓度(390μL/L和780μL/L)和固氮菌(有、无)等2因素4处理,种植菜豆饲喂刚蜕皮进入4龄的斜纹夜蛾幼虫,测定其取食和食物利用效率。协方差分析结果表明,CO2浓度与固氮菌互作对斜纹夜蛾幼虫取食量具有显著影响,在无固氮菌处理下,斜纹夜蛾幼虫对高CO2浓度处理的菜豆取食量明显高于当前CO2浓度处理的;而在有固氮菌处理下,斜纹夜蛾幼虫对高CO2浓度下菜豆的取食量又比当前CO2浓度处理下的低。固氮菌对斜夜蛾4龄幼虫最终体重没有显著影响,但高CO2浓度处理的4龄幼虫终体重大于当前CO2浓度处理的幼虫。CO2浓度、固氮菌及其互作对斜纹夜蛾幼虫的相对取食率(RCR)和相对生长率(RGR)具有显著影响,在当前CO2浓度处理下,斜纹夜蛾4龄幼虫的RCR和RGR在有、无固氮菌处理之间没有显著差异;但在升高CO2浓度下,无固氮菌处理下的RCR和RGR显著大于有固氮菌处理。CO2浓度及其与固氮菌互作显著影响近似消化率(AD),在无固氮菌处理下,CO2浓度升高使AD增大;但在有固氮菌、CO2浓度升高下,其AD略有降低。CO2浓度和固氮菌双因素处理对消化食物转化率(ECD)无显著影响。研究结果支持"补偿取食"假说。     

水稻多元有害生物为害特征及产量损失量化

收集了云南粳稻主产区沾益、寻甸两县106块稻田水稻有害生物为害和产量等信息,并用两种方法对其分析。第一种方法应用聚类分析和对应分析描述水稻有害生物为害类型和产量水平之间的关系,第二种方法应用主成分分析和多元逐步回归估计各为害的产量损失。聚类分析确定了7种有害生物为害类型,其中IN1、IN2和IN3为害水平较低,而IN5、IN6和IN7为害水平较高。有害生物为害类型和水稻产量水平之间的对应分析,在前两个轴构成的因子空间内绘出了各为害类型和产量水平的位置,并给出了一条与为害类型紧密联系的产量水平增加路线。该分析暗示与位于该因子平面右边的有害生物为害类型(IN1、IN2和IN3)相比,位于左边的为害类型(IN5、IN6和IN7)将引起水稻更大的产量损失。主成分多元回归分析评估了水稻各种病、虫、草害所造成的减产量及其相对重要性。分析结果表明,高于水稻冠层杂草、蛀茎害虫(白穗)、稻纵卷叶螟、白叶枯病、粘虫、叶瘟病和稻飞虱是该稻作区对水稻产量影响较大的为害因子。