Can microbial-based insecticides replace chemical pesticides in agricultural production?

Extensive use of chemical insecticides to control insect pests in agriculture has improved yields and production of high-quality food products. However, chemical insecticides have been shown to be harmful also to beneficial insects and many other organisms like vertebrates. Thus, there is a need to replace those chemical insecticides by other control methods in order to protect the environment. Insect pest pathogens, like bacteria, viruses or fungi, are interesting alternatives for production of microbial-based insecticides to replace the use of chemical products in agriculture. Organic farming, which does not use chemical pesticides for pest control, relies on integrated pest management techniques and in the use of microbial-based insecticides for pest control. Microbial-based insecticides require precise formulation and extensive monitoring of insect pests, since they are highly specific for certain insect pests and in general are more effective for larval young instars. Here, we analyse the possibility of using microbial-based insecticides to replace chemical pesticides in agricultural production.     

梨小食心虫生物防治研究进展

梨小食心虫Grapholita molesta(Busck)是世界性分布的果树主要害虫之一,可危害多种果树。多年来,过度依赖化学农药防治梨小食心虫效果并不理想,且杀伤天敌、污染环境、导致农药残留。利用自然天敌防治梨小食心虫高效、无毒、无污染,符合当前社会对环保的要求。本文结合前人工作,从病原微生物、寄生性天敌、捕食性天敌、性信息素、化学信息物质等方面,综述了梨小食心虫生物防治的研究进展,并对其应用前景进行了展望。     

Economic Thresholds in Soybean-Integrated Pest Management: Old Concepts, Current Adoption, and Adequacy

Increasing global demands for food underline the need for higher crop yields. The relatively low costs of the most commonly used insecticides in combination with increasing soybean market prices led growers and technical advisors to debate the adequacy of recommended economic thresholds (ETs). The adoption of ETs and pest sampling has diminished in Brazil, leading to excessive pesticide use on soybean. The reduced efficacy of natural biological control, faster pest resurgence, and environment contamination are among the side-effects of pesticide abuse. To address these problems and maximize agricultural production, pest control programs must be guided by a proper integrated pest management (IPM) approach, including the ET concept. Therefore, the most appropriate time to initiate insecticide spraying in soybean is indicated by the available ETs which are supported by experiments over the last 40 years in different edapho-climatic conditions and regions with distinct soybean cultivars. Published scientific data indicate that preventive insecticide use is an expensive and harmful use of chemicals that increases the negative impact of pesticides in agroecosystems. However, the established ETs are for a limited number of species (key pests), and they only address the use of chemicals. There is a lack of information regarding secondary pests and other control strategies in addition to insecticides. It is clear then that much progress is still needed to improve ETs for pest management decisions. Nevertheless, using the current ETs provides a basis for reducing the use of chemicals in agriculture without reducing yields and overall production, thereby improving sustainability.     

Biological control and sustainable food production

The use of biological control for the management of pest insects pre-dates the modern pesticide era. The first major successes in biological control occurred with exotic pests controlled by natural enemy species collected from the country or area of origin of the pest (classical control). Augmentative control has been successfully applied against a range of open-field and greenhouse pests, and conservation biological control schemes have been developed with indigenous predators and parasitoids. The cost-benefit ratio for classical biological control is highly favourable (1:250) and for augmentative control is similar to that of insecticides (1:2-1:5), with much lower development costs. Over the past 120 years, more than 5000 introductions of approximately 2000 non-native control agents have been made against arthropod pests in 196 countries or islands with remarkably few environmental problems. Biological control is a key component of a 'systems approach' to integrated pest management, to counteract insecticide-resistant pests, withdrawal of chemicals and minimize the usage of pesticides. Current studies indicate that genetically modified insect-resistant Bt crops may have no adverse effects on the activity or function of predators or parasitoids used in biological control. The introduction of rational approaches for the environmental risk assessment of non-native control agents is an essential step in the wider application of biological control, but future success is strongly dependent on a greater level of investment in research and development by governments and related organizations that are committed to a reduced reliance on chemical control.     

Insect pest management in African agriculture: Challenges in the current millenium

Pest management on a global scale experienced a total revolution after World War II when synthetic organic compounds were in agriculture and public health. However, it soon became apparent that there were many limitations in the use of chemicals for pest management. In agriculture, problems of pest resurgence, secondary pest outbreaks, pest resistance and adverse effects of pesticides on the environment, including human poisoning and toxicity to other non-target organisms, led to the search for alternative approaches to the pest outbreak problem. The 1960s produced new ideas on integrated pest management (IPM) strategies, followed by intensification of the search for biological control agents, which could be incorporated into IPM programmes. New application technologies were developed in the 1970s and 1980s and ecological approaches to the pest problem were spearheaded in the developed world in the 1990s, with extensive studies focused on the whole ecosystem. Important advances in crop production have also taken place in Africa in this century, involving adoption of high yielding varieties, fertilizer application, intensification of crop protection approaches, less shifting cultivation and more mono-cropping systems. However, these advances have led to increasing pest problems which unless tackled imaginatively and intelligently, they could become the most important constraint in crop production in the present millennium. Africa has entered the current millennium with relatively underdeveloped agriculture on a global scale and little investment in research on new pest management technologies that could be used to reduce crop losses. We are still highly dependent on pesticides for pest management. Therefore, the greatest challenges in agriculture in Africa will be the switch from a pesticide based mode of reducing losses due to pests to one that is ecosystem based, making use of insect management techniques which are ecologically and economically sound. Specifically, some of the major challenges in pest management in agriculture in Africa include; (i) reducing the dependence on pesticides, thus avoiding the limitations observed in the past 50 years; (ii) overcoming ignorance of the pest species and their associated community of parasites and predators which has dire consequences on the whole ecosystem; (iii) keeping out exotic pests, which in this millennium have had a devastating blow on the production of some crops and (iv) developing indigenous technologies for pest management (IPM, biocontrol, etc.) and making available to farmers materials for pest management which are affordable, safe, effective and environmentally friendly (e.g. microbial, botanicals, pheromones, genetically engineered products etc.). Both legislative and quarantine measures will have a significant role to play in pest management in the next millennium, but only when practised on a wider geographical area. Information technology (IT) will affect the way we acquire and make use of pest management strategies. Africa is therefore faced with the challenge of building up and improving its infrastructure and expertise on IT if it is to benefit pest management on the continent.     

Exploitation of insect vibrational signals reveals a new method of pest management

Food production is considered to be the main source of human impact on the environment and the concerns about detrimental effects of pesticides on biodiversity and human health are likely to lead to an increasingly restricted use of chemicals in agriculture. Since the first successful field trial, pheromone based mating disruption enabled sustainable insect control, which resulted in reduced levels of pesticide use. Organic farming is one of the fastest growing segments of agriculture and with the continuously growing public concern about use of pesticides, the main remaining challenge in increasing the safety of the global food production is to identify appropriate alternative mating disruption approaches for the numerous insect pests that do not rely on chemical communication. In the present study, we show for the first time that effective mating disruption based on substrate-borne vibrational signals can be achieved in the field. When disruptive vibrational signals were applied to grapevine plants through a supporting wire, mating frequency of the leafhopper pest Scaphoideus titanus dropped to 9 % in semi-field conditions and to 4 % in a mature vineyard. The underlying mechanism of this environmentally friendly pest-control tactic is a masking of the vibrational signals used in mate recognition and location. Because vibrational communication is widespread in insects, mating disruption using substrate vibrations can transform many open field and greenhouse based farming systems.     

农药对捕食性天敌的影响研究进展

捕食性天敌在害虫的自然控制方面起着重要作用。当害虫大发生时,需使用化学农药来进行有效控害,但化学农药会对捕食性天敌的生存造成影响。因此,了解农药对捕食性天敌的影响有利于协调化学防治和生物防治的关系。大部分农药对捕食性天敌的生长发育和繁殖表现为抑制作用,但有的为促进作用。在农药的干扰下,多数捕食性天敌的信息识别能力会降低,少部分会通过提高雄虫接收性信息素的能力或增加雌虫性信息素的释放来诱导求偶行为、增加交配频率。有的杀虫剂会影响捕食性天敌的捕食行为及捕食功能,部分杀虫剂会直接使其捕食功能模型由Holling-Ⅱ型转变为Holling-Ⅰ型。在农药胁迫下,捕食性天敌会产生抗药性,其解毒酶活性升高、保护酶活性改变及靶标部位敏感性下降可能是抗药性产生的机理。农药对捕食性天敌的影响研究在协调害虫化学防治和生物防治中有着重要的理论和现实意义,可以有效地推进捕食性天敌在害虫综合治理中的应用。     

Insect bacteria and hazelnut pests' biocontrol: the state of the art in Turkey.

Turkey is first among all hazelnut producing countries. However, it lags far behind them in terms of amount harvested per unit area. A main reason for this is that hazelnut has many agricultural pests that can not be effectively controlled. Chemical pesticides utilized to control these pests have hazardous effects on the environment. Increasing problems with resistance of these pests to most commonly used synthetic insecticides have spurred the search for alternative pest management strategies that would reduce reliance on synthetic insecticides. Biological control of hazelnut pests is an alternative control method to chemical pesticides. It is very important ecologically because of production of honey, milk and fish in the surrounding areas of hazelnut fields in Turkey. Several promising bacteriological studies have been made to find some biological control agents against these pests in Turkey. This paper presents a review of the current status of bacteriological studies on biological control of hazelnut pests in Turkey.     

Invertebrate pests of canola and their management in Australia: a review

Abstract  In Australia, canola is subject to attack by at least 30 species of invertebrate pests, although the composition of this pest complex can vary between regions. Mites (e.g. the redlegged earth mite Halotydeus destructor and the blue oat mites Penthaleus spp.), lucerne flea ( Sminthurus viridis ) and false wireworms (e.g. the grey false wireworm Isopteron punctatissimus and the bronzed field beetle Adelium brevicorne ) are the major pests threatening the seedling establishment, whereas aphids (the cabbage aphid Brevicoryne brassicae , the turnip aphid Lipaphis erysimi and the green peach aphid Myzus persicae ), the native budworm ( Helicoverpa punctigera ), the diamondback moth ( Plutella xylostella ) and the Rutherglen bug ( Nysius vinitor ) can cause irregular and unpredictable damage to the flowering and podding plants. Current tactics of pest management for canola rely largely on the use of synthetic pesticides, but this single-technology approach is likely to incur negative effects on natural enemies and the risk of pest resistance. Thus, the sustainable production of canola requires integrated pest management (IPM) strategies, in which cultural control, crop resistance and biological control are used as important components, with chemical inputs applied only when absolutely needed to restrict pests from reaching economically damaging densities. Such IPM strategies should be built around a fundamental understanding of pest ecology at both regional and local farm levels and the integration of renewable technologies. Therefore, future research efforts need to be focused on the canola-cropping system, with a particular emphasis on the impact of pest species, natural enemies of the pests, varietal resistance to pests and the spatial ecology of pest species.     

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。     

Role of nanotechnology in agriculture with special reference to management of insect pests

Nanotechnology is a promising field of interdisciplinary research. It opens up a wide array of opportunities in various fields like medicine, pharmaceuticals, electronics and agriculture. The potential uses and benefits of nanotechnology are enormous. These include insect pests management through the formulations of nanomaterials-based pesticides and insecticides, enhancement of agricultural productivity using bio-conjugated nanoparticles (encapsulation) for slow release of nutrients and water, nanoparticle-mediated gene or DNA transfer in plants for the development of insect pest-resistant varieties and use of nanomaterials for preparation of different kind of biosensors, which would be useful in remote sensing devices required for precision farming. Traditional strategies like integrated pest management used in agriculture are insufficient, and application of chemical pesticides like DDT have adverse effects on animals and human beings apart from the decline in soil fertility. Therefore, nanotechnology would provide green and efficient alternatives for the management of insect pests in agriculture without harming the nature. This review is focused on traditional strategies used for the management of insect pests, limitations of use of chemical pesticides and potential of nanomaterials in insect pest management as modern approaches of nanotechnology.     

Production and use of biological pest control agents

Biological pest control agents are gaining prominence for the control of insect pests in agriculture and forestry. The shift from chemical control has been due to environmental concerns and recent innovations in biotechnology. Production and use of biological insect control agents is the challenge of the future for pest management.     

Mechanisms for flowering plants to benefit arthropod natural enemies of insect pests： Prospects for enhanced use in agriculture

Reduction of noncrop habitats, intensive use of pesticides and high levels of disturbance associated with intensive crop production simplify the farming landscape and bring about a sharp decline of biodiversity. This, in turn, weakens the biological control ecosystem service provided by arthropod natural enemies. Strategic use of flowering plants to enhance plant biodiversity in a well-targeted manner can provide natural enemies with food sources and shelter to improve biological control and reduce dependence on chemical pesticides. This article reviews the nutritional value of various types of plant-derived food for natural enemies, possible adverse effects on pest management, and the practical application of flowering plants in orchards, vegetables and field crops, agricultural systems where most research has taken place. Prospects for more effective use of flowering plants to maximize biological control of insect pests in agroecosystem are good but depend up on selection of optimal plant species based on information on the ecological mechanisms by which natural enemies are selectively favored over pest species.     

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.     

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.     

稻飞虱灾变机理及可持续治理的基础研究

稻飞虱(褐飞虱、白背飞虱和褐飞虱)是威胁我国粮食安全最大的生物灾害。本文基于稻飞虱致害能力的高度变异性、对农药的高适应性、传播病毒病和具有远距离迁飞能力等特点,以及研究中存在的稻飞虱迁飞动态、致害性变异和种间互作关系等灾变机理机制不清楚,提出了稻飞虱迁飞时空动态、致害性变异、稻飞虱传播的病毒病、农药对稻飞虱及其天敌的生态毒理效应、稻飞虱基因组数据分析和稻田生态系统对稻飞虱种群数量调控功能6个研究发展方向以阐明稻飞虱灾变的内在机理,为稻飞虱可持续治理体系建设提供理论依据。     

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.     

Vertical farming systems bring new considerations for pest and disease management

Vertical farming is an emerging area of food production that aims to provide sustainable intensification of agriculture by maximising the obtainable yield per unit area of land. This approach commonly utilises stacked horizontal levels of crop growth in glasshouse or controlled environment (CE) facilities. Vertical farming has, however, received relatively little scientific investigation to date. Consequently, important factors such as economic feasibility, system design and optimisation of production methods are still being evaluated. Vertical farming methods bring additional considerations for the effective management of pests and diseases compared with conventional protected horticulture, such as movement of both pest and beneficial insects between growth levels. This article aims to provide a perspective on the positive and negative issues facing pest and disease control in Vertical farming systems. We highlight important considerations for system optimisation and areas for future investigation.     

Living fencerows of the Rio San Miguel,Sonora, Mexico: Traditional technology for floodplain management

In southwestern North America, agriculture is limited by both arable land and available water supplies. In the upper Rio San Miguel, as well as in other narrow river valleys of eastern Sonora, Mexico, floodplain farming is dependent upon living fencerows for its environmental stability. Propagated fencerows of willow and cottonwood maintain, extend, and enhance floodplain fields. These ecological filters also protect fields from cattle, harbor agents of biological control of pests, and provide renewable supplies of wood. Traditional Sonoran farmers do not perceive cottonwoods and willows as phreatophytic pests, as their Anglo-American neighbors do. The stability of the upper San Miguelagroecosystem con-trasts with severely eroded conditions within the region's other arid watersheds.     

Characterization of Farmer’s knowledge and management practices of papaya mealybug Paracoccus magnatus (Hemiptera: Pseudococcidae) in Tanzania

Papaya mealybug (PMB) is a serious insect pest for papaya production in Sub-Saharan Africa, limiting production potential in farming communities. We did a household survey to evaluate the Characteristics of farmers' knowledge, challenges, and current (PMB) control practices in four papaya growing regions of Tanzania namely, Tanga, Dodoma, Pwani, and Katavi involving 100 papaya farmers. The study found that 96% of farmers reported PMB, as a major challenge in papaya production. Very few (0.8%) of the farmers were knowledgeable on insect pest identification. Chemical pesticides were the only option for PMB control, and 43.0% of farmers were able to access and apply. We also found that 36.4% of the farmers were aware of the adverse effects of chemical pesticides. Furthermore, the study observed that 0.3% of farmers use botanical pesticides. Additionally, the study observed that 44.1% of farmers use control measures against PMB, the remaining 55.9% did not practice any control measure, thus leading to low papaya yields observed in the study regions. Our findings provide insights to farmers into the use of plant-based pesticides, mainly plant essential oils, and its benefits that may promote farmers' attitudes towards increasing papaya yield and reducing chemical pesticide use to avoid pest resistance.