Insect pest management in the age of synthetic biology

Arthropod crop pests are responsible for 20% of global annual crop losses, a figure predicted to increase in a changing climate where the ranges of numerous species are projected to expand. At the same time, many insect species are beneficial, acting as pollinators and predators of pest species. For thousands of years, humans have used increasingly sophisticated chemical formulations to control insect pests but, as the scale of agriculture expanded to meet the needs of the global population, concerns about the negative impacts of agricultural practices on biodiversity have grown. While biological solutions, such as biological control agents and pheromones, have previously had relatively minor roles in pest management, biotechnology has opened the door to numerous new approaches for controlling insect pests. In this review, we look at how advances in synthetic biology and biotechnology are providing new options for pest control. We discuss emerging technologies for engineering resistant crops and insect populations and examine advances in biomanufacturing that are enabling the production of new products for pest control.     

植物源活性物质对昆虫生殖的干扰作用

昆虫的繁盛与其强大的生殖能力密切相关,而环境友好的植物源活性物质是可持续的害虫防治方法之一,能够通过多种作用机制影响昆虫的生殖发育。本文从昆虫生殖行为、生长发育、生殖细胞或器官、生殖地位与性比、共生微生物等方面,综述了植物源活性物质对昆虫生殖干扰机理的研究进展及相关的应用情况,以期为昆虫生殖发育干扰的进一步研究与害虫综合防控技术的研发提供参考。     

Avoiding conflicts between insect and weed biological control: selection of non-target species to assess host specificity of cabbage seedpod weevil parasitoids

Abstract:  Classical biological control of insect pests and weeds may lead to potential conflicts, where insect pests are closely related to weed biological control agents. Such a conflict may occur in the classical biological control of the cabbage seedpod weevil, Ceutorhynchus obstrictus (Marsham) in North America, which belongs to the same subfamily, Ceutorhynchinae, as a number of agents introduced or proposed for introduction against non-indigenous invasive weed species. We propose a step-by-step procedure to select non-target species and thereby to develop a non-target species test list for screening candidate entomophagous biological control agents of a herbivore pest insect in a way that would simultaneously evaluate non-target potential on weed biological control agents and other non-target species. Using these recommendations, we developed a non-target test list for host specificity evaluations in the area of origin (Europe) and the area of introduction (North America) for cabbage seedpod weevil parasitoids. Scientifically based predictions on expected host–parasitoid interactions and ecological information about the ecological host range in the area of origin can help avoid conflicts, while still allowing the introduction of safe and effective agents against both insect pests and weeds.     

Recombinant entomopathogenic agents: a review of biotechnological approaches to pest insect control

Although the use of chemical pesticides has decreased in recent years, it is still a common method of pest control. However, chemical use leads to challenging problems. The harm caused by these chemicals and the length of time that they will remain in the environment is of great concern to the future and safety of humans. Therefore, developing new pest control agents that are safer and environmentally compatible, as well as assuring their widespread use is important. Entomopathogenic agents are microorganisms that play an important role in the biological control of pest insects and are eco-friendly alternatives to chemical control. They consist of viruses (non-cellular organisms), bacteria (prokaryotic organisms), fungi and protists (eukaryotic organisms), and nematodes (multicellular organisms). Genetic modification (recombinant technology) provides potential new methods for developing entomopathogens to manage pests. In this review, we focus on the important roles of recombinant entomopathogens in terms of pest insect control, placing them into perspective with other views to discuss, examine and evaluate the use of entomopathogenic agents in biological control.     

Why study diapause?

This review highlights a number of reasons why insect diapause merits attention. Knowledge of diapause is essential for understanding the seasonal biology of an insect species, and such information is also required for the development of effective pest management strategies; manipulating domesticated species used in pollination and silk production; developing accurate predictive models used to forecast periods of pest abundance; and increasing the shelf‐life of parasitoids and predatory mites used in the biological control industry. Mechanisms used by diapausing insects to survive low temperature may provide tips for cryopreserving insect stocks, a vital need within the research community. Diapause also presents an interesting model for probing fundamental questions in development, and we are indebted to diapause studies for early insights into insect hormones. In addition, I argue that insect diapause may provide insights into questions on aging, obesity and disease transmission, and diapausing insects offer a potentially rich source of pharmaceutical agents that may contribute to improvement of human health.     

Biocontrol: The Potential of Entomophilic Nematodes in Insect Management

A review of the development of entomophilic nematology and a commentary on the potential of entomophilic nematodes in controlling insect pests. The paper considers some of the major contributions to our knowledge of entomophilic nematology; factors involved in insect pest management and how they are applicable to the use of nematodes; nematodes which are most promising as biological control agents; and problems to be solved to facilitate the use of entomophilic nematodes in insect management.     

A New Approach to Quantify Semiochemical Effects on Insects Based on Energy Landscapes

Introduction

Our ability to document insect preference for semiochemicals is pivotal in pest control as these agents can improve monitoring and be deployed within integrated pest management programmes for more efficacious control of pest species. However, methods used to date have drawbacks that limit their utility. We present and test a new concept for determining insect motivation to move towards, or away from, semiochemicals by noting direction and speed of movement as animals work against a defined energy landscape (environmentally dependent variation in the cost of transport) requiring different powers to negotiate. We conducted trials with the pine weevils Hylobius abietis and peach-potato aphids Myzus persicae exposed to various attractants and repellents and placed so that they either moved up defined slopes against gravity or had to travel over variously rough surfaces.

Results

Linear Mixed Models demonstrated clear reductions in travel speed by insects moving along increasingly energetically taxing energy landscapes but also that responses varied according to different semiochemicals, thus highlighting the value of energy landscapes as a new concept to help measure insect motivation to access or avoid different attractants or repellents across individuals.

Conclusions

New sensitive, detailed indicators of insect motivation derived from this approach should prove important in pest control across the world.     

Rearing beneficial insects for biological control purposes in resource poor areas of africa

Biological control of insect pest and weeds using beneficial insects in resource poor areas is not very well supported. Poor funding has affected in particular the importation of classical biological control agents, quarantine, rearing, research facilities, and the research programmes. Donor agencies, commercial and semi-commercial enterprises in a number of African countries have, however, been able to contribute to biological control efforts using beneficial insects by providing some of the resources needed. This has led to biological control becoming a real possibility to control insect pests and weeds in several resource poor countries. Examples are provided of the “spin-offs” of such programmes for resource poor areas in South Africa, Zambia, Kenya, Malawi, Benin and Nigeria. Conventional insect rearing, insect conservation and habitat management as an aid to biological control programmes are discussed.     

Theory,Technology, and Practice of Site-Specific Insect Pest Management

Insects are usually unevenly distributed throughout an area in nature. Despite this knowledge, analytical methods and technology have limited insect pest management to uniform management decisions in the field. Recently, the methods and technology to map and analyze insect spatial distribution have been developed to a level where the uneven nature of insect populations can be considered for application of pest management tactics. This new approach to insect management is termed site-specific pest management. Site-specific pest management utilizes spatial information about pest distribution to apply control tactics only where pest density is economically high within a field. This review will detail the current status of site-specific insect pest management in agriculture, technological requirements, its limitations, and future potential.     

我国农业害虫综合防治研究现状与展望

害虫综合防治作为农业生产的一项重要策略,在农业可持续发展中具有举足轻重的作用。近年来,针对我国害虫防治所存在的技术需求,科技部等部门先后通过973计划、863计划、科技支撑计划和农业行业专项等对重要害虫防治研究立项支持。通过这些项目的实施,我国建成了一支由国家和省级科研单位和大学组成的专业科研队伍和研究平台,对害虫监测预警技术、基于生物多样性保护利用的生态调控技术、害虫生物防治技术、化学防治技术、抗虫转基因作物利用技术等方面的研究取得了一系列的重要进展,研究建立了棉花、水稻、玉米、小麦和蔬菜等作物重要害虫的综合防治技术体系,并在农业生产中发挥了重要作用。以基因工程和信息技术为代表的第二次农业技术革命的到来,推动了害虫综合防治的理论发展,为害虫综合防治技术的广泛应用提供了新的机遇。地理信息系统、全球定位系统等信息技术和计算机网络技术的应用,提高了对害虫种群监测和预警的能力和水平,转基因抗虫作物的商业化种植等技术的应用显著增强了对害虫种群的区域性调控效率。针对产业结构调整和全球气候变化所带来的害虫新问题,进一步发展IPM新理论与新技术将成为我国农业昆虫学研究的重要方向之一。     

Steroid conjugates: Synthesis and preliminary biological testing of pro-juvenoids

A series of 10 new pro-juvenoids (juvenogens, insect hormonogenic compounds, pro-drug-like agents) was synthesized using isomeric synthetic juvenoids (insect juvenile hormone analogs) and steroid molecules as patterns modifying parts of the complex hormonogenic molecules. In addition, several new synthons were prepared, which were required by the designed synthetic protocol to achieve the target molecules. These pro-juvenoids were subjected to the topical screening tests and to the drinking assays on the red firebug (Pyrrhocoris apterus), a convenient model laboratory phytophagous insect. Simple and efficient synthetic procedures for the preparation of the target pro-juvenoids and their synthons are presented. Furthermore, the biological activity of the pro-juvenoids in comparison with the activity of their parent juvenoids and that of several commercially available agents is demonstrated. Juvenoids and pro-juvenoids may replace toxic insecticides persistent in the insect pest control because they have no adverse effects on non-target organisms and/or human.     

Compatibility of Photoactive Dyes with Insect Biocontrol Agents

Integrated pest management (IPM) programmes often look for more specific ways to control pests. Biological control agents, such as the bacterium, Bacillus thuringiensis Berliner, and the fungus, Beauveria bassiana (Balsamo) Vuillemin, can control insects with minimal disturbance to the environment because of their host specificity and short half-lives. Often these agents alone cannot prevent yield loss or are too expensive. This study looked at the in vitro combination of these agents and photoactive dyes, especially phloxine B (red dye D&C 28), a Food and Drug Administration approved dye, with the intent to provide better insect control. Photoactive dyes are being tested for the control of many pest insects. Phloxine B and related xanthene dyes, eosin y, fluorescein and rose bengal inhibited the growth of both B. thuringiensis and B. bassiana . Phloxine B was the most inhibitory and fluorescein the least inhibitory dye for both microbes. The magnitude of inhibition increased with increasing concentration of dye and light intensity. Therefore, an adverse effect on the field performance of these biological control agents in combination with xanthene dyes would be expected.     

Insect neuropeptides: Structures,chemical modifications and potential for insect control

Insect neuropeptides are involved in almost all physiological processes in insects, such as diuresis, ecdysis, pheromone biosynthesis and control of muscle activity. Thus, these small peptide hormones and their receptors are promising targets for a novel generation of selective and non-neurotoxic insecticides. However, due to poor bioavailability, pharmacokinetics and short half-life the peptides themselves cannot be used as insect control agents. The past two decades have seen an increase in research into the discovery of non-peptide small molecules that function as mimics for neuropeptides. This review presents an overview on structure–activity studies, conformational analyses and peptidomimetic modifications of selected insect neuropeptides with a special potential for application in pest control.     

转Bt基因抗虫棉的生态风险及治理对策

评述了转Bt基因抗虫棉的生态风险及治理对策。其生态风险主要表现在目标害虫的抗性和对非目标生物群落的变化。目标害虫与转基因抗虫棉的互相作用和抗虫棉杀虫毒素的时空表达方式是目标害虫抗性发展的主要途径。在转基因抗虫棉田中,虽然对目标害虫的防治次数大为减少,但害虫和天敌群落的稳定性仍不如常规棉田,某种次要害虫大发生的可能性较大。认为将转基因抗虫棉纳入综合防治体系并培育更加高效的抗虫棉是治理目标害虫抗性和防止次要害虫上升的重要措施。     

The biotechnology of Bacillus thuringiensis

One of the challenges in the application of biotechnology to pest control is the identification of agents found in nature which can be used effectively. Biotechnology offers the potential of developing pesticides based on such agents which will provide environmentally sound and economically feasible insect control alternatives. Such an agent, the insect pathogen Bacillus thuringiensis, is the subject of intense investigations in several laboratories. Insecticides which use the entomocidal properties of B. thuringiensis are currently produced and sold worldwide; new products are currently in the development stage. Herein, the biology and genetics of B. thuringiensis and the problems associated with current products are critically reviewed with respect to biotechnology. Moreover, the economic and regulatory implications of technologically advanced products are evaluated.     

Current status of the management of fall webworm,Hyphantria cunea: Towards the integrated pest management development

The fall‐webworm (FWW), Hyphantria cunea, is a highly polyphagous insect pest that is native to North America and distributed in different countries around the world. To manage this insect pest, various control methods have been independently evaluated in the invaded areas. Some of the control methods have been limited to the laboratory and need further study to verify their effectiveness in the field. On the other hand, currently, integrated pest management (IPM) has become a promising ecofriendly insect pest management option to reduce the adverse effect of insecticides on the environment. The development of an IPM for an insect pest must combine different management options in a compatible and applicable manner. In the native areas of the insect pests, there are some recommended management options. However, to date, there is no IPM for the management of the FWW in the newly invaded areas. Therefore, to develop an IPM for this insect pest, compilation of effective management option information is the first step. Thus, believing in the contribution of an IPM to the established management strategies, the chemical, biological, natural enemy, sex pheromone, and molecular studies regarding this insect were reviewed and potential future research areas were delineated in this review study. Therefore, using the currently existing management options, IPM development for this insect pest should be the subject of future research in the newly invaded areas.     

21世纪害虫管理的一些特征展望

分析了近年来国内外IPM研究的进展 ,认为未来的害虫管理是以作物的控害作用为中心 ,以农田生态系统或区域性生态系统为对象 ,以大量信息管理为基础 ,以发展新技术 (转基因作物和昆虫性信息素 )和农民参与为重点 ,以生态调控为手段 ,以持续发展为方向。从而使害虫管理提高到一个新的境界     

害虫研究与防治中的生态学尺度

尺度已成为生态学上的一个重要概念和研究热点 ,但在害虫防治中尚未引起足够的重视 .本文从生态学尺度概念和等级理论出发 ,分析了不同尺度水平上害虫研究的方法、内容、关键问题及研究成果对害虫防治的意义 .在对害虫发生为害特征、害虫种群动力学原理、农业生态系统结构的演变、害虫防治的社会化、害虫防治技术的发展等因素的分析的基础上 ,指出害虫防治策略在时空尺度上拓展的趋势和必要性 .     

Insect control with baculoviruses

Baculoviruses have been researched extensively for insect control. Three of their features have been particularly attractive: their host specificity and consequential environmental safety, their virulence in host insects, and their capability for causing disease epizootics. There have been four approaches to their use for insect control: as microbial insecticides for short-term insect population suppression, through seasonal colonization or a recurring "booster shot" for control of more than one pest generation, through introduction-establishment where the viral species or strain was not indigenous, and through environmental manipulation to make the ecosystem more favorable for viral epizootics. Actual usage of baculoviruses in pest management has been disappointing, particularly with the microbial insecticide approach, primarily for three reasons: economics, slow speed of kill, and adverse effects of the environment on the viruses. The recombinant-DNA revolution has greatly increased the prospects for baculoviruses in insect pest management.     

植物标本馆防虫方法

虫害是植物标本保藏的最大威胁。防虫一直是植物标本馆管理工作的重点。在中国科学院华南植物研究所标本馆70多年管理经验的基础上,近年来在标本保藏技术上不断改进,探索出一些实用的防虫措施和方法,如：驱虫剂、低温冷冻净化法、熏蒸法等。