Future prospects for application of insect pathogens as a component of integrated pest management in tropical root crops

Insect pests and phytophagous mites cause a considerable loss to tropical root crops in the field. Major pests include the sweet potato weevil Cylas puncticollis, cassava mealybug Phenacoccus manihoti, cassava green spider mite Mononychellus tanajoa, yam beetle Heteroligus meles, and taro hornworm Hippotion celerio. Field and laboratory evaluation experiments indicate that entomopathogenic microorganisms may be adequately used in the management of insect and mite pests in root crops. The highest promise probably lies with fungal pathogens (Beauvaria bassiana, Hirsutella thompsonii, Metarhizium anisopliae, Nomuraea rileyi, Entomophthora thaxteriana, and E. parvispora), but bacterial (Bacillus thuringiensis), microsporidian (Nosema locustae) nematode (Steinernema feltiae) and even viral (Baculoviruses) pathogens may be exploited in an integrated pest management programme of tropical root crop pests.     

基因组学时代害虫治理的研究进展及前景

随着DNA测序技术的不断更新和生物信息学的快速发展,昆虫基因组学的研究与日俱增,提高了人们对种群遗传学和进化生态学的理解和认识,促进了对重要农业害虫的适应性和致害机理的研究,为安全、有效、可持续地开展害虫综合治理提供了新思路和新手段。近两年来,全球发布的昆虫基因组数量每年可达30个。在遗传学、生态学和进化论等生命科学基本原理和方法的指导下,基因组学的研究为揭示害虫遗传变异的内在机制、生态适应性策略和种群变动规律提供了重要的数据和信息资源,同时催生了一系列害虫治理新技术和新方法的研发与应用。为了进一步促进和加强基因组时代的害虫治理研究,拓展该领域研究的广度与深度,本文就昆虫基因组的研究,昆虫与植物协同进化模式及其互作机理,昆虫免疫和抗药性分子机制,以及害虫防治新技术等方面进行了综述,旨在为了解基因组时代害虫治理的研究进展及前景提供参考,对进一步改进害虫生态控制的策略和措施也具有指导意义。     

重组病毒杀虫剂应用研究进展

应用分子生物学技术可以将昆虫特异性的毒素基因、某些酶基因等外源基因插入昆虫病毒基因组,或通过改造昆虫病毒基因组等方法构建重组病毒杀虫剂,提高杀虫效果。温室及田间释放实验证实,重组病毒杀虫剂可以显著提高现场防治效果。连续多代抗性筛选实验表明,宿主被诱导产生对重组病毒杀虫剂抗性的速度低于野生型病毒杀虫剂。采用在剂型中添加光增白剂等保护剂、在基因组中插入具有增效作用的基因、应用病毒增强蛋白等技术可以提高重组病毒杀虫效果。随着基因工程技术的发展和安全性研究的深入,以重组杆状病毒为主的重组昆虫病毒杀虫剂的应用研究正面临着突破。     

Improved quality management to enhance the efficacy of the sterile insect technique for lepidopteran pests

Lepidoptera are among the most severe pests of food and fibre crops in the world and are mainly controlled using broad spectrum insecticides. This does not lead to environmentally sustainable control and farmers are demanding alternative control tools which are both effective and friendly to the environment. The sterile insect technique (SIT), within an area‐wide integrated pest management (AW‐IPM) approach, has proven to be a powerful control tactic for the creation of pest‐free areas or areas of low pest prevalence. Improving the quality of laboratory‐reared moths would increase the efficacy of released sterile moths applied in AW‐IPM programmes that integrate the (SIT). Factors that might affect the quality and field performance of released sterile moths are identified and characterized in this study. Some tools and methods to measure, predict and enhance moth quality are described such as tests for moth quality, female moth trapping systems, ‘smart’ traps, machine vision for recording behaviour, marking techniques, and release technologies. Methods of enhancing rearing systems are discussed with a view to selecting and preserving useful genetic traits that improve field performance.     

Soil application of Beauveria bassiana GHA against apple sawfly,Hoplocampa testudinea (Hymenoptera: Tenthredinidae): Field mortality and fungal persistence

Low impact alternatives to synthetic insecticides for the control of apple sawfly (Hoplocampa testudinea Klug) are scarce encumbering pest management in organic apple orchards. We investigated the soil persistence and field efficacy of the entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin (BotaniGard) against apple sawfly under common organic orchard practices. We also assessed the efficacy of B. bassiana GHA and Metarhizium brunneum Petch (indigenous strain) against sawfly in the laboratory. Larvae treated with either fungus in the laboratory died faster than control larvae and displayed 49.4%–68.4% mycosis. In the field, B. bassiana density remained high in the week after application, during larval descent to the soil. Fungal density decreased to 25% at 49 d after application and to 0.4% after 55 weeks. Molecular markers revealed that the majority of fungal isolates recovered comprised the applied B. bassiana strain GHA. Larvae pupating in soil cages in the orchard for 49 d displayed 17% mycosis. The high efficacy under laboratory conditions was not seen in the field. B. bassiana application resulted in densities above the upper natural background level during the growing season, but reversion to background levels occurred within a year. It remains to be investigated whether this has a detrimental effect on nontarget organisms. Additional work is needed to bridge the knowledge gap between laboratory and field efficacy in orchards.     

昆虫化学信息物质及其在害虫综合治理上的应用

本文阐述了昆虫化学信息物质的定义和分类,昆虫的化学通讯原理,以及利用化学信息物质在害虫综合治理上的应用。     

Herbivore response to habitat manipulation with floral resources: a study of the cabbage root fly

Biological control of pest insects can be improved by providing natural enemies with additional food resources such as floral nectar within the production field. However, herbivores may also benefit from this practice. The aim of this 3‐year field study was to investigate if dill and buckwheat, aimed as food resources for natural enemies, could increase the densities of the cabbage root fly, Delia radicum L. (Diptera: Anthomyiidae), a severe pest on crucifers. Differences in egg density, numbers of pupae and sex ratio were compared between cabbage plots with or without flowers. Habitat manipulation by intercropping flowering plants with cabbage did not increase the overall D. radicum egg density in our 3‐year study, and there were no significant differences in egg numbers between treatments in any year. No effect on the fecundity of D. radicum was observed, most likely because of the high mobility and feeding behaviour of the female flies, combined with high abundance and diversity of other food sources around the fields during this period. Despite equal egg numbers, fewer pupae were found in plots with flowers than without in one of three studied years. This finding suggests that natural enemies attacking larvae and pupae of D. radicum were either more abundant or efficient in cabbage plots with flowers.     

Efficacy of some biorational insecticides against Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) under laboratory and greenhouse conditions in Kuwait

The tomato leafminer, Tuta absoluta, is one of the most destructive pests of tomato worldwide. Management of the pest is mainly based on chemical insecticides. Reliance on insecticides is difficult to sustain because of unintended long‐term adverse effects on the environment and human health. Consequently, there is a need to develop pest management strategies that ensure the production of high‐quality products, while at the same time ensuring environmental sustainability and maximum consumer protection. We evaluated the efficacy the biopesticides: Azadirachtin, Bacillus thuringiensis, Steinernema feltiae and Beauveria bassiana individually and in combination against T. absoluta under laboratory and greenhouse conditions. When second instar larvae were exposed to tomato leaf discs treated with Azadirachtin (3 g / L), B. thuringiensis (0.5 g/L) or B. bassiana (1.5 g/L), 70%–86%, 55%–65%, and 45.5%–58.5% mortality was observed, respectively. Steinernema feltiae (1,000 IJs/ml) was the least effective biopesticide, with 26%–42% mortality. In the greenhouse trials on tomato, pest infestation (mines/10 leaves/plant) and fruits damaged were significantly lower on plants treated with Azadirachtin  +  B. thuringiensis or Azadirachtin  +  B. bassiana compared to plants treated with Azadirachtin, B. thuringiensi, B. bassiana or S. feltiae alone. Azadirachtin  +  B. thuringiensis and Azadirachtin  +  B. bassiana resulted in 90% and 81% reduction in fruits damaged in the summer experiments, respectively, and 96% and 91% in winter. The most severe pest infestation was observed on plants treated with S. feltia. The results indicate that the biopesticides, except S. feltia, can contribute to T. absoluta control in greenhouse tomato crops. In particular, the combined use of Azadirachtin with B. thuringiensis or B. bassiana provided the highest level of control of the pest. The potential for including these biopesticides in an overall sustainable integrated pest management programme for T. absoluta is discussed.     

Suggestions for unifying the terminology in biological control

This paper gives suggestions forunifying the terminology in biological controlacross different research disciplines, such asbiological control of arthropods, weeds andplant pathogens. It is suggested that use ofthe term `biological control' is restricted tothe use of living organisms. Four strategiesof biological control are outlined anddefined: (1) Classical biological control, (2) Inoculation biological control, (3) Inundationbiological control, and (4) Conservationbiological control. It is proposed to usethese four terms as defined, and avoid usageof the term `augmentation'. Terms for specificprocesses and modes of action (for example,`parasitoid' and `competitor') can be definedby usage within the different biologicalcontrol disciplines. Microbial control usuallyindicates biological control of invertebratesusing microbes and, as such, is a subdivisionof biological control. Use of additionalauxiliary terms such as biopesticide isdiscussed.     

贵州玉米田害虫绿色灯光防控技术研究

为探明贵州玉米田昆虫群落结构和杀虫灯对害虫的防治效果,选取贵州玉米田3个具有代表性的点分别安装诱虫灯,进行诱集调查,并对近灯区（距离灯20 m以内）、远灯区（距离灯20~150 m）和对照区的昆虫种群消长情况进行田间调查。结果表明,贵州玉米田昆虫共有11目66科132种,主要为同翅目、鞘翅目、鳞翅目、膜翅目、直翅目、双翅目和半翅目类昆虫;灯诱共获得89个种类,其中害虫占64.77%,益虫占15.91%,中性昆虫占19.32%。田间调查结果显示,近灯区物种丰富度最高,对照区次之,远灯区最低;近灯区玉米螟Ostrinia furnacalis、黏虫Mythimna seperata (Walker)、灰飞虱Laodelphax striatellus和条赤须盲蝽Trigonotylus coelestialium (Kirkaldy)等趋光性昆虫的种群数量长期高于其他区域。综上所述,风吸式诱虫灯对玉米田害虫有较好的防治效果,为玉米田害虫的绿色防控提供了参考。     

Synergistic effects of Trichoshield on enhancement of growth and resistance to downy mildew in pearl millet

Trichoshield, a talc formulation consisting of spores of Trichoderma harzianum, Trichoderma lignorum, Gliocladium virens and Bacillus subtilis was tested, following different application methods, for its ability to promote growth of pearl millet plants and to induce resistance to downy mildew of pearl millet. Under laboratory conditions, trichoshield seed treatment enhanced seed germination and seedling vigor of pearl millet significantly over the control; under greenhouse conditions vegetative growth parameters like height, fresh and dry weight, leaf area and number of tillers were significantly enhanced over the control: Trichoshield formulation offered greater protection against downy mildew in comparison with individual strains of T. harzianum, T. lignorum, G. virensand B. subtilis. Among the methods of application, foliar spray was found to be a more efficient delivery method than seed treatment or slurry treatment. Combinations of foliar spray with seed treatment and slurry treatment produced the same effect as foliar spray alone. Under field conditions, trichoshield treatment enhanced reproductive parameters like number of earheads, length and girth of earheads, 1000 seed weight and yield significantly over the control. Days required for 50% flowering was reduced by 4 days compared to the control. Yield enhancement of 28% over the control was highly significant. Trichoshield treatment offered protection ranging from 52 to 71% under field conditions, depending on the application method. However, the chemical fungicide metalaxyl Apron provided the highest protection against downy mildew, both under greenhouse and field conditions.     

Management of orthopteran pests: a conservation perspective

Although the vast majority of orthopterans are not pests, some species have the potential to cause serious damage to human interests. Management of pest populations frequently conflicts with conservation of orthopteran species and processes, particularly when the pest species or its ecological processes are susceptible to extinction or when the pest population is coincident with non-target orthopterans. With respect to chemical control, the greatest hazards are the broad-spectrum, highly lethal properties of most agents, which can be mitigated with formulation and application methods. Biological control risks permanent, large-scale changes to orthopteran species and processes which can be minimized with bioinsecticidal and other short-lived or selective formulations and reliable host-range testing. Cultural control may have large-scale, broad-spectrum impacts to non-target orthopterans, but these hazards can be diminished by appropriate testing and monitoring. Mechanical control methods may be impractically labour intensive, but they are highly target specific and therefore warrant further consideration. Social control measures such as education, insurance and compensation programmes appear to have little direct potential for harm to orthopteran conservation, but the complex socioeconomic and, ultimately, environmental consequences of such programmes have not been assessed. The melding of orthopteran pest management and conservation requires that we perceive these insects and their ecological processes to be vital elements of sustainable agroecosystems. Our management of orthopterans (both non-target and pest populations) must focus on keeping good stewards on the land.     

三北地区灌木林重大害虫与治理对策

对我国三北地区灌木林主要虫灾及控制措施进行简要评述。根据灌木林生态系统的特点,指出在控制策略上应立足生态调控,重点开展监测与预警,以及各种诱杀技术、抗性树种(品系)的选择与多树种合理配置等技术,使其具有较好的自我调节和保持系统稳定性的能力。最后,简要介绍灌木林重大害虫沙棘木蠹蛾Holcocerus hippop haecolus Hua,Chou,Fang et Chen和沙蒿(Artemisia spp.)上4种钻蛀性害虫的研究进展。     

麦套夏播转Bt基因棉R93-6对昆虫群落的影响

以转Bt(Bacillusthuringiensis)基因棉品系R93-6为试验材料,以中棉所16号为对照,研究了在麦套夏播条件下转基因棉对昆虫群落的影响。结果表明,转基因棉田昆虫群落、害虫和天敌亚群落的多样性指数和均匀度指数均低于常规棉田,而优势集中性则高于常规棉田,所以转基因棉田昆虫群落、害虫和天敌亚群落的稳定性不如常规棉田,某种害虫大发生的可能性较大。对季节性变化格局的研究表明,转基因棉田昆虫群落可以划分为前期(6月初至7月下旬)、中期(7月底至8月底)和后期(9月份以后)三个发展阶段,根据不同阶段害虫和天敌发生的特点, 提出了害虫综合治理的策略。即前期害虫的防治应以生物生态调控为主;中期以化学防治为主,以生物生态调控为辅,协调好生物防治和化学防治的矛盾;后期应以生物生态调控为主,并加强农业防治。     

Expression of epoxide hydrolase in insect cells: a focus on the infected cell

Insect cell culture and the baculovirus vector expression system have emerged to be a promising production technique for heterologous proteins. In this article, expression characteristics for membrane-bound epoxide hydrolase are examined. A generic process is presented whereby cells are grown in serum-free media supplemented with serum and then resuspended in serum-free media to simplify purification after infection. The infected cells retain significant metabolic activity during the postinfection stage. Thus, maintaining nutrient supply during the postinfection period is critical, and a low stirring rate will result in oxygen depletion and shift the metabolism of the infected cells toward lactate production which then lowers product yield. This is the first report indicating that glucose is supplied from sucrose decomposition and then metabolized for viral DNA and recombinant protein production in recombinant baculovirus insect expression system. (c) 1993 John Wiley & Sons, Inc.     

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.     

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     

Perception and knowledge of the Sirex woodwasp and other forest pests in South Africa

• 1 Sirex noctilio F. (Siricidae: Hymenoptera) is one of the most serious invasive pests of pine. In South Africa, there has been a national effort to control S. noctilio, including a campaign to increase awareness of the pest amongst the local forestry community.
• 2 We considered the impacts that the arrival of the pest and the awareness campaign have had on perceptions and knowledge of S. noctilio, as well as other forestry pests, amongst members of the forestry community.
• 3 For data collection, a survey questionnaire was developed and used in telephone interviews.
• 4 The results obtained in the present study showed that the Sirex awareness campaign had increased knowledge of forestry pests in general but basic knowledge regarding the identification and symptoms of specific pests, such as S. noctilio, was poor. This will negatively influence monitoring efficacy.
• 5 Traditional paper‐based media and personal contact contributed most to enhanced awareness. Electronic media were less effective and improvement would require a more focused effort. It was of concern that private farmers and contractors, as well as non‐European first language speakers, were less well informed about forestry pests.
• 6 Clearly, a fragmented landscape in terms of ownership and language, presents challenges for effective communication of forestry pest threats.