Pesticidal natural products – status and future potential

There is a long history of using natural products as the basis for creating new pesticides but there is still a relatively low percentage of naturally derived pesticides relative to the number of pharmaceuticals derived from natural sources. Biopesticides as defined and regulated by the US Environmental Protection Agency (EPA) have been around for 70 years, starting with Bacillus thuringiensis, but they are experiencing rapid growth as the products have got better and more science‐based, and there are more restrictions on synthetic chemical pesticides. As such, biopesticides are still a small percentage (approximately US$3–4 billion) of the US$61.3 billion pesticide market. The growth of biopesticides is projected to outpace that of chemical pesticides, with compounded annual growth rates of between 10% and 20%. When integrated into crop production and pest management programs, biopesticides offer the potential for higher crop yields and quality than chemical‐only programs. Added benefits include reduction or elimination of chemical residues, therefore easing export, enabling delay in the development of resistance by pests and pathogens to chemicals and shorter field re‐entry, biodegradability and production using agricultural raw materials versus fossil fuels, and low risk to non‐target organisms, including pollinators. Challenges to the adoption of biopesticides include lack of awareness and education in how to deploy their unique modes of action in integrated programs, testing products alone versus in integrated programs, and lingering perceptions of cost and efficacy. © 2019 Society of Chemical Industry     

Integrated pest management of coffee for small-scale farmers in East Africa: needs and limitations

Coffee in East Africa (Kenya, Tanzania and Uganda) is an important cash and export crop for small-scale farmers. The crop suffers heavy yield losses due to damage caused by a wide range of indigenous pests (insects, diseases, nematodes and weeds). Current recommended pest control measures include a combination of cultural, resistant/tolerant cultivars and the use of broad spectrum chemical pesticides. Chemical pesticides are far more popular at the farm level than any of the other recommended pest control measures. Coffee pest control strategies are often aimed at individual pests with little consideration of the implications for the total coffee pest complex and its agro-ecosystem. This unilateral approach has resulted in increased pest pressure on coffee and some of its companion crops, outbreak of new pests of coffee, development of pest strains resistant to the cheap and commonly available chemical pesticides, increased environmental problems, increased health risks to man and livestock and an overall increase in the costs of coffee production, thus forcing many farmers to neglect their coffee plantations. Measures to alleviate the above problems, particularly the high production costs, are needed to improve coffee production and increase the cash return to the small-scale farmer. Integrated pest management (IPM) offers the best prospects for solving the above problems. However, lack of national IPM policies, poor extension systems, inefficient research-extension-farmer linkage and the lack of a holistic approach will delay the development and implementation of appropriate, acceptable and sustainable IPM practices.     

海洋真菌次级代谢产物在植物保护中的研究与应用

病虫害严重影响我国农业生产,每年造成巨额经济损失,传统化学农药虽然在一定程度上能够减轻这些危害,但其不合理的使用也造成严重的负面影响,亟需开发新型生物农药。海洋真菌生存于独特的海洋环境中,形成了有别于陆生真菌的生存繁殖方式和遗传代谢机制,能够产生许多结构新颖、生物活性显著的次级代谢产物,其中许多化合物具有抗植物病原菌、杀虫和抗病毒等农用生物活性,具有开发成为新型生物农药的巨大潜力。本文综述了2010年以来前人在海洋真菌次级代谢产物农用生物活性方面的研究成果,涵盖了90个化合物,结构类型主要包括聚酮类、萜类、生物碱类和甾体类化合物等,以期为生物农药的开发提供依据。     

Botanical Pesticides and Their Mode of Action

Pest management is facing economic and ecological challenge worldwide due to human and environmental hazards caused by majority of the synthetic pesticide chemicals. Identification of novel effective insecticidal compounds is essential to combat increasing resistance rates. Botanical pesticides have long been touted as attractive alternatives to synthetic chemical pesticides for pest management because botanicals reputedly pose little threat to the environment or to human health. The body of scientific literature documenting bioactivity of plant derivatives to arthropod pests continues to expand, yet only a handful of botanicals are currently used in agriculture in the industrialized world, and there are few prospects for commercial development of new botanical products. Pyrethrum and neem are well established commercially, pesticides based on plant essential oils have entered the marketplace, and the use of rotenone appears to be waning. A number of plant substances have been considered for use as pest antifeedants, repellents and toxicants, but apart from some natural mosquito repellents, a little commercial success has ensued for plant substances that modify arthropod behavior. Several factors appear to limit the success of botanicals, most notably regulatory barriers and the availability of competing products (newer synthetics and fermentation products) that are cost-effective and relatively safe compared with their predecessors. In the context of agricultural pest management, botanical pesticides are best suited for use in organic food production in industrialized countries but can play a much greater role in the production and postharvest protection of food in developing countries. Botanicals have been in use for a long time for pest control. The compounds offer many environmental advantages. However, their uses during the 20th century have been rather marginal compared with other bio-control methods of pests and pathogens. Improvement in the understanding of plant allelochemical mechanisms of activity offer new prospects for using these substances in crop protection. I’m trying in this article to present different kinds of botanical pesticides came from different recourses and their mode of actions as well as I will try to examine the reasons behind their limited use (disadvantages) and the actual crop protection developments involving biopesticides of plant origin for organic or traditional agricultures to keep our environment clean and safer for humankind and animals.     

Integrated crop management, the basis for environment friendly crop protection of potatoes

Relatively large amounts of pesticides are needed to control diseases and pests in modern, intensive potato production. Integrated crop management offers a way of reducing the need for pesticides. It aims to reduce costs and improve the quality of the product and of the production methods, while maintaining soil fertility and the quality of the environment. The components of integrated crop management are described. Prevention of diseases and pests has high priority. If diseases or pests are present, non-chemical control methods are preferred and chemical control is based on economic criteria and the monitoring of the soil and crops. The contribution of integrated crop management to the control of two important fungal diseases, late blight (Phytophthora infestans), and stem canker (Rhizoctonia solani) and of one pest, potato cyst nematode (Globodera spp..) is described. The prospects for further development of integrated crop protection are discussed.     

Genetically engineering better fungal biopesticides

Microbial insect pathogens offer an alternative means of pest control with the potential to wean us off our heavy reliance on chemical pesticides. Insect pathogenic fungi play an important natural role in controlling disease vectors and agricultural pests. Most commercial products employ Ascomycetes in the genera Metarhizium and Beauveria. However, their utilization has been limited by inconsistent field results as a consequence of sensitivity to abiotic stresses and naturally low virulence. Other naturally occurring biocontrol agents also face these hurdles to successful application, but the availability of complete genomes and recombinant DNA technologies have facilitated design of multiple fungal pathogens with enhanced virulence and stress resistance. Many natural and synthetic genes have been inserted into entomopathogen genomes. Some of the biggest gains in virulence have been obtained using genes encoding neurotoxic peptides, peptides that manipulate host physiology and proteases and chitinases that degrade the insect cuticle. Prokaryotes, particularly extremophiles, are useful sources of genes for improving entomopathogen resistance to ultraviolet (UV) radiation. These biological insecticides are environmentally friendly and cost‐effective insect pest control options. © 2017 Society of Chemical Industry     

真菌防治蝗虫研究进展

蝗虫是世界性重大成灾害虫,时常在草原、沙漠区或农作区暴发为害.当前的非洲沙漠蝗灾害再次提醒人们,蝗灾依然是粮食生产和生态安全的严重威胁.在寻求绿色可持续防蝗的新策略新技术研究中,昆虫病原真菌显现出种类多、毒力强、易规模化生产及环境友好等明显优势而倍受重视.近30年,真菌防蝗研究和应用进步加快,国际、国内都有真菌防蝗产品...     

Frankliniella occidentalis (Pergande) integrated pest management programs for fruiting vegetables in Florida

BACKGROUND: The spread of the western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), resulted in the worldwide destabilization of established integrated pest management programs for many crops. Efforts to control the pest and the thrips‐vectored tospoviruses with calendar applications of broad‐spectrum insecticides have been unsuccessful. The result has been a classic ‘3‐R’ situation: resistance to numerous insecticides; resurgence of the western flower thrips populations as a result of natural predators and native competitor thrips being eliminated; replacement by various other pests. This paper reports on integrated pest management programs for fruiting vegetables that are effective, economical, ecologically sound and sustainable. RESULTS: The components include the following: define pest status (economic thresholds); increase biotic resistance (natural enemies and competition); integrate preventive and therapeutic tactics (scouting, ultraviolet‐reflective technologies, biological control, compatible insecticides, companion plants and fertility); vertically integrate the programs with other pests; continually communicate latest science‐based management tactics with end‐users. CONCLUSION: These programs have been widely implemented in Florida and have significantly improved the management of western flower thrips and thrips‐transmitted viruses. Copyright © 2012 Society of Chemical Industry     

Determinants of farmers’ decisions on pesticide use in oriental tobacco: a survey of common practices

Information about pesticide use and perceptions of their risks among farmers is important for identifying problems associated with pest-control decisions and developing appropriate management practices in given crops. In tobacco, a plant sensitive to many pests and diseases, such information is lacking. The patterns of pesticide use in oriental tobacco, as well as the most important factors for farmers’ decisions relating to chemical pest control were studied among randomly selected farmers in northern Greece on the basis of self-reported information acquired through a pre-tested questionnaire. High reliance of farmers on pesticides and field use of all well-known classes of chemical pesticides were reported. While all the active ingredients reported were registered for pest control in tobacco, they differed considerably in terms of toxicity. A normal cropping season received at least 14–16 pesticide applications for soil disinfection, pest control, and weed control. Most farmers stated that they usually spray chemicals on a calendar basis or on the first appearance of a pest. Efficacy on target pests and market price of the pesticide products to be used were the most important criteria for selection of pesticides, i.e. products that are considered to be highly effective and/or that are cheap are more likely to be selected. Better-educated and more experienced farmers were found to pay more attention to environmental safety and pesticide toxicity. Most farmers felt that pesticide use can reduce crop damage by more than 75%, assuring high yields. Main determinants of pesticide use were primarily the fear of severe yield and economic losses and the doubts about the effectiveness and the correct implementation of alternative pest-control methods. Pesticide use could be reduced by exposing farmers to improved pest-control practices such as site-specific integrated pest management.     

Managing the risk of insect resistance to transgenic insect control traits: practical approaches in local environments

BACKGROUND: Growers have enthusiastically embraced crops genetically modified to express Bacillus thuringiensis (Bt) proteins for insect control because they provide excellent protection from key damaging insect pests around the world. Bt crops also offer superior environmental and health benefits while increasing grower income. However, insect resistance development is an important concern for all stakeholders, including growers, technology providers and seed companies that develop these genetically modified crops. Given the marked benefits associated with Bt crops, insect resistance management (IRM) must be a consideration when cultivating these crops. RESULTS: The technical data and practical experience accumulated with Bt crops in many global regions can inform different aspects of resistance management leading to robust, science‐based IRM plans. A range of elements should be considered in assembling any IRM strategy, including: pest biology/ecology, product deployment patterns, local cropping systems, insect susceptibility monitoring, stakeholder/grower communications, and a remedial action plan should resistance develop. Each of these elements is described in more detail, with specific examples of how these elements can be combined and tailored to the local/regional environments and grower practices. CONCLUSION: IRM plans need to be suitable for the given production situation. What works for large monoculture production systems in North America is unlikely to be appropriate for the small, more diverse agriculture of southeast Asia or Africa. Though it is clear that Bt crops impart considerable value to growers, it is also clear that it is in the best interest of all stakeholders to preserve Bt proteins for the long‐term benefits they provide. Copyright © 2009 Society of Chemical Industry     

Pest status and control of blister beetles in West Africa

Abstract

During recent years, blister beetles have gained importance in species diversity and as pests of food crops in West Africa. Among the 97 species reported, Psalydolytta fusca Oliv, and P. vestita Duf. are economically important beetle species. Beetle abundance is generally associated with the flowering of crops in a region. Regular intensive weeding and early crop establishment are recommended for pest management in food crops. Global pest control strategies are discussed in the context of subsistence agriculture.     

药源植物在草地贪夜蛾防控中的应用研究进展

草地贪夜蛾作为世界重大迁飞性害虫,自2019年侵入我国,已对我国的玉米、甘蔗等多种作物造成了较大经济损失。采用化学合成农药防治草地贪夜蛾的弊端已逐步显现,找到可以替代化学合成农药的手段十分必要,其中植物源药剂是重要的替代途径。目前,全世界已报道了80余种在草地贪夜蛾防控中具有应用前景的药源植物,以菊科植物资源最丰富,还有唇形科和豆科等植物;这些植物的提取物中包含对草地贪夜蛾具有控制作用的活性组分,主要包括萜类、类黄酮、生物碱、脂肪酸类等,其对草地贪夜蛾的作用方式主要包括胃毒、触杀、生长发育调节、拒食、抑制细胞增殖、诱导细胞凋亡等。药源植物提取物在对草地贪夜蛾的防控中具有持续防效明显、作用靶标多样、不易产生抗药性和环境友好等特点,开发应用前景广阔。     

Pest control in coffee

Coffee pests have been estimated to cause losses of about 13% of the world yield but are most serious in Africa, particularly where Arabica coffee is grown. Coffee pests are normally indigenous and except for the berry borer beetle (Hypothenemus hampei Ferrari) there has been little movement between the main production areas. There is a great variety of pests but because the crop is perennial, evergreen and only grown in areas without climatic extremes, pest populations only rarely become intolerable, being held in check for most of the time by parasites, predators and diseases. Routine spraying of insecticides in coffee plantations is undesirable for these kill parasites and predators and often result in pest outbreaks. An effective but simple integrated control system has been evolved over many decades in East Africa, using a combination of cultural, biological and chemical control. Pest numbers are monitored continuously by growers and insecticides are used as selectively as possible. The system is ideally suited to areas where labour is cheap but technology is expensive.     

Potential of biopesticides in agriculture

All living organisms are subject to predation, parasitism or competition from other organisms. The study of these interactions has led to the identification of many potential opportunities for the use of living organisms as biopesticides to protect agricultural crops against insect pests, fungal, bacterial and viral diseases, weeds, nematodes and mollusc pests. A range of biopesticide products (including as active agents bacteria, fungi, nematodes, protozoa, viruses and beneficial insects) are now available commercially for control of insect pests, fungal and bacterial diseases and weeds. However, world biopesticide sales in 1990 were estimated to be $120 million, representing less than 0–5% of the world agrochemical market. Over 90% of biopesticide sales are represented by a single product type, containing Bacillus thuringiensis Berl., for control of insect pests. Nevertheless, biopesticide sales are estimated to be increasing at 10–25% per annum whilst the world agrochemical market is static or even shrinking. There has been a significant renewal of commercial interest in biopesticides as evidenced by the substantial number of alliances forged between major agrochemical companies and biotechnology companies which allow these major companies access to marketing rights to novel biopesticides. This paper reviews the current commercial status of biopesticides and discusses the technical and commercial constraints which have impeded development of biopesticides in the past. Novel developments in R&D, which may enable some of these constraints to be overcome, are examined by reference to a number of specific examples (some of which arise from the author's own experience in a biotechnology company). The future prospects for biopesticides are discussed in the light of technical advances and commercial and regulatory requirements.     

苹果主要病虫害全程生物农药防控效果

为研究苹果主要病虫害全程生物农药防控效果,2020、2021年在苹果休眠期使用石硫合剂和腐殖酸铜,在生长期选择多种生物农药,包括苦参碱、中生菌素、多抗霉素、大黄素甲醚、枯草芽胞杆菌、苏云金芽胞杆菌和鱼藤酮等,监测了苹果斑点落叶病、褐斑病、苹果黄蚜和苹果小卷叶蛾的发生与为害。结果显示,2020年全程喷施生物农药对苹果斑点落叶病、褐斑病、苹果黄蚜和苹果小卷叶蛾的防治效果最低值分别为82.08%、80.07%、86.04%和86.77%;2021年则分别为87.90%、86.90%、89.67%和88.25%,均接近于化学农药为主的防控区。同时,生物农药防控区未出现任何药害。研究表明苹果全生育期喷施生物农药,可有效控制苹果主要病虫害,对苹果园化学农药减施增效具有重要指导意义。     

Agricultural nematology in East and Southern Africa: problems,management strategies and stakeholder linkages

By 2050, Africa's population is projected to exceed 2 billion. Africa will have to increase food production more than 50% in the coming 50 years to meet the nutritional requirements of its growing population. Nowhere is the need to increase agricultural productivity more pertinent than in much of Sub‐Saharan Africa, where it is currently static or declining. Optimal pest management will be essential, because intensification of any system creates heightened selection pressures for pests. Plant‐parasitic nematodes and their damage potential are intertwined with intensified systems and can be an indicator of unsustainable practices. As soil pests, nematodes are commonly overlooked or misdiagnosed, particularly where appropriate expertise and knowledge transfer systems are meager or inadequately funded. Nematode damage to roots results in less efficient root systems that are less able to access nutrients and water, which can produce symptoms typical of water or nutrient deficiency, leading to misdiagnosis of the underlying cause. Damage in subsistence agriculture is exacerbated by growing crops on degraded soils and in areas of low water retention where strong root growth is vital. This review focuses on the current knowledge of economically important nematode pests affecting key crops, nematode control methods and the research and development needs for sustainable management, stakeholder involvement and capacity building in the context of crop security in East and Southern Africa, especially Kenya, Tanzania, Uganda and Zimbabwe. © 2015 Society of Chemical Industry     

Regulatory problems associated with natural products and biopesticides

For registration, the United States Environmental Protection Agency (USEPA) separates pesticides into conventional chemical pesticides and biochemical and microbial pesticides. Natural products generally fall into the latter category. The USEPA has specified the test requirements for registration in the United States in the guidelines for registration of biorational pesticides (Subdivision M of 40 CFR Part 158). A discussion of the regulatory issues requires some reference to the accompanying scientific developments. The potential application of chemicals that affect insect behavior and development appeared an extremely promising approach to the reduction of adverse environmental and health impacts associated with many conventional pesticides. In addition to these benefits, the new biopesticides generally affected a very specific range of target species. However, although juvenile hormones and semiochemicals offer exciting new approaches to pest control, and are potentially valuable components of pest management strategies, acceptance of these techniques has been slow. Commercial development has been difficult for several reasons. Regulatory requirements may appear burdensome. Unconventional pest-control technologies may call for special formulations or application equipment. It may not be easy to establish the efficacy of non-lethal potential techniques. Investigators who derive funds from the public sector may have neither responsibility nor resources to carry the technology beyond the experimental stage. Because most activities in this field have been heavily research-oriented, few workers have possessed the additional resources to obtain safety data or data to satisfy regulatory requirements. Difficulties in preparing and administering guidelines for registration of biopesticides lie in the novelty of the pest control agents and the diversity of the techniques involved in their effective use. Rapid advances in molecular biology and other disciplines continually strain the capabilities of regulators who are responsible for making safety assessments regarding pest-control agents. Although regulatory authorities are familiar with conventional pesticides, safety assessment of biopesticides calls for totally different approaches.     

草地贪夜蛾对农药主要抗性机制的概述

草地贪夜蛾Spodoptera frugiperda是一种迁飞性害虫,源自美洲,已入侵非洲和亚洲部分国家并暴发成灾,2019年初入侵我国,严重威胁着我国玉米、小麦等粮食作物。目前草地贪夜蛾的防治主要依赖于化学农药和种植转基因作物。因长期使用农药,草地贪夜蛾已经对氨基甲酸酯类、有机磷酸酯类和拟除虫菊酯类等多种杀虫剂产生了不同程度的抗性。草地贪夜蛾对不同种类杀虫剂表现的抗性机制不同,主要有代谢抗性和靶标抗性2种。本文主要从代谢抗性和靶标抗性2个方面分别综述了草地贪夜蛾对不同种类杀虫剂的抗性机制,分析草地贪夜蛾对不同杀虫剂的抗性作用方式,并对草地贪夜蛾抗药性管理和监测进行展望。     

United States Department of Agriculture-Agricultural Research Service research on managing insect resistance to insecticides

Insecticide resistance has developed within many classes of pesticide, and over 500 species of insects and mites are resistant to one or more insecticides. Insecticide resistance and the consequent losses of food and fiber caused by failure to control insect and mite pests causes economic losses of several billion dollars worldwide each year. It is the goal of insect resistance management (IRM) to preserve useful pesticides by slowing, preventing or reversing development of resistance in pests. Important aspects of this goal are understanding the development of resistance and monitoring to determine ways to prevent its development. We describe programs specific to missions of the US Department of Agriculture, Agricultural Research Service, which are designed to characterize insecticide resistance in insects and mites with the goal of managing pests in an ecologically acceptable manner. Resistance management of cotton, potatoes, vegetables, melons, ornamentals, greenhouse crops, corn, stored grains, livestock, honeybees and mites, as well as management of transgenic crops are evaluated. We conclude that IRM is a vital part of stewardship of any pest management product and must be a combined effort of manufacturers, growers, consultants, extension services and grower organizations, working closely with regulators, to achieve logistically and economically feasible systems that prolong the effectiveness of all pest-control products.     

Development of the Multi-nucleocapsid Nucleopolyhedroviruses (MNPVs) Infectious to Loopers (Lepidoptera: Noctuidae: Plusiinae) as Microbial Control Agents

A number of the members of the Noctuidae (subfamily Plusiinae) are polyphagous insects that infest a variety of economically important crops world-wide. These hosts include but are not limited to cotton, vegetable and field crops and also such specialty crops as mint. Many of these crops require multiple applications of chemical pesticides to protect them from various loopers and other economic pests. One proposed alternative to the use of chemical pesticides to protect these crops is the development of insect-specific viruses of the family Baculoviridae. Hundreds of these viruses of the genus Nucleopolyhedrovirus have been isolated, many from economically important Lepidoptera. The advent of the discovery that some of these viruses may have a broad host range increased the interest in the development of them as microbial agents throughout the world. The broad host range (over 30 species in some cases) provided the possibility to control not only one species, but a complex of lepidopterous pests infesting specific or multiple crops. From the 1960s to the present, extensive basic and applied research has been conducted on the multi-nucleocapsid (MNPV) forms within which a broad host range appears to be characteristic. Of these, the virus isolated from the alfalfa looper, Autographa californica (Speyer) (AcMNPV) has been the most studied, particularly as related to microbial control. Two of the viruses isolated from loopers have been registered in the USA. Although efficacy has been demonstrated for loopers, there is a paucity of data on the other important species that may simultaneously infest looper hosts. Because of their relatively slow action, the viruses will probably be used in integrated programs with chemical pesticides applied during critical periods of high population pressure. Further research needs to be conducted to establish efficacy for other hosts, improved production methods either in vivo or in vitro, increased field persistence as related to timing and frequency of applications, and finally the utility of genetically engineered MNPVs as microbial pesticides. The potential of these organisms has been demonstrated and new developments are being made to increase the overall efficiency and economics of their use. These improvements can only increase interest in use of the baculoviruses in pest management systems for loopers and other pests.