Western corn rootworm (Diabrotica virgifera virgifera LeConte) population dynamics

1 The western corn rootworm Diabrotica virgifera virgifera LeConte is a major insect pest of field maize, Zea mays L. Larvae can cause substantial injury by feeding on maize roots. Larval feeding may destroy individual roots or root nodes, and reduce plant growth, stability, and yield. Costs associated with managing corn rootworms in continuous maize are annually one of the largest expenditures for insect management in the United States Corn Belt.
2 Even though D. virgifera virgifera has been studied intensively for over 50 years, there is renewed interest in the biology, ecology, and genetics of this species because of its ability to rapidly adapt to management tactics, and its aggressive invasive nature.
3 This article provides a comprehensive review of D. virgifera virgifera population dynamics, specifically: diapause, larval and adult development, seasonality, spatial and temporal dynamics at local and landscape scales, invasiveness in North America and Europe, and non-trophic interactions with other arthropods.
4 Gaps in current knowledge are identified and discussed especially within the context of challenges that scientists in North America and Europe are currently facing regarding pest dynamics and the need to develop appropriate management strategies for each geographic area.     

Insect pest densities across site-specific management zones of irrigated corn in northeastern Colorado

The ability to manage insect pests in a site-specific manner is hindered by the costs and time required to describe pest densities and distributions. The purpose of this study was to determine whether insect pest distributions are related to site-specific management zones (SSMZs). Site-specific management zones, as described in this study, delineate fields into three zones of similar yield potential: high, medium, and low productivity. If insect densities vary across SSMZs, it is possible that management decisions could be made at the SSMZ level instead of treating the whole field. This research was conducted during summers 2001 and 2002 on cooperators' farms in northeastern Colorado. Surveys were conducted within corn, Zea mays L., fields, so that densities of three common insect pests of Colorado corn could be compared across SSMZ. The three insect pests were western corn rootworm, Diabrotica virgifera virgifera LeConte; European corn borer, Ostrinia nubilalis (HiAbner); and western bean cutworm, Richia albicosta (Smith). D. v. virgifera larvae and adults were most common in the high-productivity SSMZ. O. nubilalis larval abundance was similar at three fields, whereas in a fourth field the larvae were most common in the high-productivity SSMZ. In one field that contained substantial numbers of R. albicosta, egg abundance was similar across SSMZs, whereas larvae were most common in the high-productivity SSMZ. Site-specific management zones seemed to correlate well with the abundance of some insect pests and might prove useful for managing insects in a site-specific manner.     

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。     

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.     

Combining intercropping with semiochemical releases: optimization of alternative control of Sitobion avenae in wheat crops in China

Overreliance on pesticides has large environmental and human health costs that compel researchers and farmers to seek alternative management tactics for crop pests. For insect pests, increasing crop species diversity via intercropping and using semiochemicals to alter local arthropod populations have separately proven effective at reducing pest densities. Here, we combine these two tactics in an effort to gain better control of Sitobion avenae (Fabricius) (Hemiptera: Aphididae), the English grain aphid, a major pest of cereal production worldwide. We conducted field experiments over 2 years testing the effectiveness of combining intercropping of wheat and oilseed rape with release of methyl salicylate (MeSA). We found that maximum and mean aphid densities were highest in wheat monocultures, significantly lower in intercropped plots and MeSA plots, and lowest when intercropping and MeSA release were combined by obtaining highest densities of predatory lady beetles and parasitoids rates. Importantly, grain yield and quality showed a similar pattern: they were highest for combined intercropped/MeSA plots, intermediate in plots with intercropping or MeSA alone, and lowest in control monoculture plots. Our results suggest that combining these two tactics holds significant promise for improved management of aphid populations and emphasize the need to integrate alternative pest control approaches to optimize sustainable insect pest management.     

Analysis of the spatio-temporal distribution of Eurygaster integriceps (Hemiptera: Scutelleridae) by using spatial analysis by distance indices and geostatistics

Eurygaster integriceps Puton (Hemiptera: Scutelleridae) is the most serious insect pest of wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) in Iran. In this study, spatio-temporal distribution of this pest was determined in wheat by using spatial analysis by distance indices (SADIE) and geostatistics. Global positioning and geographic information systems were used for spatial sampling and mapping the distribution of this insect. The study was conducted for three growing seasons in Gharamalek, an agricultural region to the west of Tabriz, Iran. Weekly sampling began when E. integriceps adults migrated to wheat fields from overwintering sites and ended when the new generation adults appeared at the end of season. The adults were sampled using 1- by 1-m quadrat and distance-walk methods. A sweep net was used for sampling the nymphs, and five 180° sweeps were considered as the sampling unit. The results of spatial analyses by using geostatistics and SADIE indicated that E. integriceps adults were clumped after migration to fields and had significant spatial dependency. The second- and third-instar nymphs showed aggregated spatial structure in the middle of growing season. At the end of the season, population distribution changed toward random or regular patterns; and fourth and fifth instars had weaker spatial structure compared with younger nymphs. In Iran, management measures for E. integriceps in wheat fields are mainly applied against overwintering adults, as well as second and third instars. Because of the aggregated distribution of these life stages, site-specific spraying of chemicals is feasible in managing E. integriceps.     

Swede midge (Diptera: Cecidomyiidae), ten years of invasion of crucifer crops in North America

The Swede midge, Contarinia nasturtii Kieffer (Diptera: Cecidomyiidae), a common insect pest in Europe, is a newly invasive pest in North America that constitutes a major threat to cruciferous vegetable and field crops. Since its first identification in Ontario, Canada, in 2000, it has rapidly spread to 65 counties in the provinces of Ontario and Quebec and has recently been found in canola (one of two cultivars of rapeseed, Brassica napus L. and Brassica campestris L.) in the central Prairie region where the majority of Canada's 6.5 million ha (16 million acres) of canola is grown. The first detection of Swede midge in the United States was in 2004 in New York cabbage (Brassica oleracea L.), but it has now been found in four additional states. Here, we review the biology of Swede midge, its host plant range, distribution, economic impact, pest status, and management strategies. We provide insight into this insect's future potential to become an endemic pest of brassica crops in North America. We also proposed research needed to develop tactics for handling this invasive pest in brassica crops.     

A review of the biology,ecology and control of saddle gall midge,Haplodiplosis marginata (Diptera: Cecidomyiidae) with a focus on phenological forecasting

Saddle gall midge Haplodiplosis marginata (Diptera: Cecidomyiidae) is a pest of cereals across Europe. The occasional nature of this pest has resulted in limited and sporadic research activity. There remain important gaps in knowledge due either to a genuine lack of research or to previous research being difficult to access. These knowledge gaps make the development of effective control options difficult. Here, we review the existing literature in an attempt to consolidate the information on H. marginata from research which spans several decades and encompasses many different countries. The current distribution and pest status of this insect are updated, along with the methods of cultural and chemical control available to growers. The biology and life history of the insect are described in detail and the ecological processes governing them are discussed. A forecasting model is presented which allows the emergence of this pest in the UK to be predicted from degree day data, and the potential application of this model in management decisions is discussed. Finally, the areas in most need of further research are identified, along with suggestions of how this information can be used to help develop effective and sustainable management solutions for this pest.     

陕西省栎黄枯叶蛾蛹的空间分布

栎黄枯叶蛾(Trabala vishnou gigantina Yang)是近年来在陕西吴起沙棘林中大面积暴发的一种食叶害虫,为了解其种群空间结构,有效控制危害,利用地统计学等方法,对不同坡向和疏密度沙棘纯林中的栎黄枯叶蛾蛹的空间分布进行了研究。结果表明:栎黄枯叶蛾化蛹的高峰期为8月中旬,雄性幼虫较雌性幼虫平均早3.7 d化蛹;蛹在阴坡的东南向和阳坡的西、北两方向分布比例最大;在距沙棘树基部30.00—75.00 cm范围处分布密集。由全方向的变异函数曲线分析得知:阴坡密林、阴坡疏林、阳坡密林、阳坡疏林中,栎黄枯叶蛾蛹的空间依赖范围分别为95.609、47.379、79.238、42.415 m,空间变异值分别为0.760、0.561、0.649、0.407;且在阴阳两坡向的密林中均呈聚集分布,疏林中均呈随机分布。用Kriging插值方法生成的空间分布图显示蛹在空间分布上存在一定的边缘效应,且方向性较明显。     

Modelling the effects of population aggregation on the efficiency of insect pest control

A methodology is developed to assess the effects of spatial distribution on the efficiency of insect pest control. This methodology is especially applicable to pest control methods whose efficiency of action depends either positively or negatively on pest density It is applied here to the sterile insect technique and pheromone trapping for male annihilation, which both depend negatively on density. This methodology relies on quantifying clumps of various size and then relating this to efficiency of control and predicting the total pest production given the information on clump sizes and efficiency of control for each clump size. It is found that control is about four times as difficult for a population that is highly clumped (k of the negative binomial distribution=0.25) as for a regularly dispersed population.     

Spatial Pattern of Attacks of the Invasive Woodwasp Sirex noctilio,at Landscape and Stand Scales

Invasive insect pests are responsible for important damage to native and plantation forests, when population outbreaks occur. Understanding the spatial pattern of attacks by forest pest populations is essential to improve our understanding of insect population dynamics and for predicting attack risk by invasives or planning pest management strategies. The woodwasp Sirex noctilio is an invasive woodwasp that has become probably the most important pest of pine plantations in the Southern Hemisphere. Our aim was to study the spatial dynamics of S. noctilio populations in Southern Argentina. Specifically we describe: (1) the spatial patterns of S. noctilio outbreaks and their relation with environmental factors at a landscape scale; and (2) characterize the spatial pattern of attacked trees at the stand scale. We surveyed the spatial distribution of S. noctilio outbreaks in three pine plantation landscapes, and we assessed potential associations with topographic variables, habitat characteristics, and distance to other outbreaks. We also looked at the spatial distribution of attacked trees in 20 stands with different levels of infestation, and assessed the relationship of attacks with stand composition and management. We found that the spatial pattern of pine stands with S. noctilio outbreaks at the landscape scale is influenced mainly by the host species present, slope aspect, and distance to other outbreaks. At a stand scale, there is strong aggregation of attacked trees in stands with intermediate infestation levels, and the degree of attacks is influenced by host species and plantation management. We conclude that the pattern of S. noctilio damage at different spatial scales is influenced by a combination of both inherent population dynamics and the underlying patterns of environmental factors. Our results have important implications for the understanding and management of invasive insect outbreaks in forest systems.     

Feasibility,limitation and possible solutions of RNAi‐based technology for insect pest control

Abstract Numerous studies indicate that target gene silencing by RNA interference (RNAi) could lead to insect death. This phenomenon has been considered as a potential strategy for insect pest control, and it is termed RNAi‐mediated crop protection. However, there are many limitations using RNAi‐based technology for pest control, with the effectiveness target gene selection and reliable double‐strand RNA (dsRNA) delivery being two of the major challenges. With respect to target gene selection, at present, the use of homologous genes and genome‐scale high‐throughput screening are the main strategies adopted by researchers. Once the target gene is identified, dsRNA can be delivered by micro‐injection or by feeding as a dietary component. However, micro‐injection, which is the most common method, can only be used in laboratory experiments. Expression of dsRNAs directed against insect genes in transgenic plants and spraying dsRNA reagents have been shown to induce RNAi effects on target insects. Hence, RNAi‐mediated crop protection has been considered as a potential new‐generation technology for pest control, or as a complementary method of existing pest control strategies; however, further development to improve the efficacy of protection and range of species affected is necessary. In this review, we have summarized current research on RNAi‐based technology for pest insect management. Current progress has proven that RNAi technology has the potential to be a tool for designing a new generation of insect control measures. To accelerate its practical application in crop protection, further study on dsRNA uptake mechanisms based on the knowledge of insect physiology and biochemistry is needed.     

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.     

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。     

苹果蠹蛾的综合防控和遗传控制研究进展

苹果蠹蛾是仁果类水果的重要检疫害虫,在世界各地造成了巨大的经济损失。目前对其化学防治、化学生态调控、病毒等防治方法研究较多,但仍不能满足防控该害虫的需要,对新型防控技术的需求日益增强。不育昆虫释放技术(SIT)是一种可控制甚至根除靶标害虫的环境友好型防控技术,但传统SIT技术存在一定的局限性,如较难区分性别与筛选雌雄虫、辐射不育昆虫的交配竞争力和适合度降低等问题,这些缺陷随着昆虫遗传修饰技术的发展将得以解决,并将在害虫防控进程中起到积极作用。本文综述了苹果蠹蛾主要防控技术研究现状,介绍了通过遗传修饰技术改善SIT的技术策略,并综合分析了我国开展苹果蠹蛾遗传修饰研究情况和将其应用在苹果蠹蛾防控体系中的可行性及优势。     

入侵害虫西花蓟马的生物学、危害及防治技术

西花蓟马Frankliniellaoccidentalis最早发生于北美地区,现已广泛分布于世界各地,是园艺作物最重要的害虫之一。早在1996年,西花蓟马就被我国农业部列为进境植物检疫潜在的危险性害虫,2003年夏季西花蓟马在北京部分保护地首次发现。该文从分布及危害、寄主植物、生物学特性和防治方法4个方面对该害虫进行了概述。     

植物-昆虫间的化学通讯及其行为控制

在植物与昆虫间的化学通讯中植物气味物质起着决定性的作用,它调控着昆虫的多种行为,诸如引诱昆虫趋向寄主植物,刺激昆虫取食,引导昆虫选择产卵场所,进行传粉和防御昆虫等。有些植物则当受到食植性昆虫危害时会释出一些引诱害虫天敌的化学信号。这些化学信号是一些挥发性萜类混合物,天敌昆虫就以此来区分受害和未受害植株。尽管目前在害虫综合治理中,昆虫信息素的应用越来越显得比天然植物气味源更受重视,但是必须指出的是,昆虫信息化合物首次成功地使用于植物保护的却是天然植物气味源。在利用植物气味源作害虫测报和防治中,近年来一种简单价廉的粘胶诱捕器己成为多种害虫的标准测报工具。在害虫综合治理中利用植物气味源的技术显然是具有不可估量的潜力。文中提出了利用基因工程技术来改造植物,使植物能释放特定的驱避剂或其它控制昆虫行为的特殊气味物质的新概念。     

转基因昆虫的应用研究进展

综述转基因昆虫技术的应用研究:转基因昆虫为农林害虫的防治提供了新策略,为削弱媒介昆虫传播能力提供了新方法;该技术已成为一种重要的分析基因功能的实验工具;同时转基因昆虫还是生产高附加值蛋白和昆虫自身改良的重要手段之一,文章还对转基因昆虫的应用前景作了展望。     

Conceptual framework and rationale

The sterile insect technique (SIT) has been shown to be an effective and sustainable genetic approach to control populations of selected major pest insects, when part of area-wide integrated pest management (AW-IPM) programmes. The technique introduces genetic sterility in females of the target population in the field following their mating with released sterile males. This process results in population reduction or elimination via embryo lethality caused by dominant lethal mutations induced in sperm of the released males. In the past, several field trials have been carried out for mosquitoes with varying degrees of success. New technology and experience gained with other species of insect pests has encouraged a reassessment of the use of the sterility principle as part of integrated control of malaria vectors. Significant technical and logistic hurdles will need to be overcome to develop the technology and make it effective to suppress selected vector populations, and its application will probably be limited to specific ecological situations. Using sterile males to control mosquito vector populations can only be effective as part of an AW-IPM programme. The area-wide concept entails the targeting of the total mosquito population within a defined area. It requires, therefore, a thorough understanding of the target pest population biology especially as regards mating behaviour, population dynamics, dispersal and level of reproductive isolation. The key challenges for success are: 1) devising methods to monitor vector populations and measuring competitiveness of sterile males in the field, 2) designing mass rearing, sterilization and release strategies that maintain competitiveness of the sterile male mosquitoes, 3) developing methods to separate sexes in order to release only male mosquitoes and 4) adapting suppression measures and release rates to take into account the high reproductive rate of mosquitoes. Finally, success in area-wide implementation in the field can only be achieved if close attention is paid to political, socio-economic and environmental sensitivities and an efficient management organization is established taking into account the interests of all potential stakeholders of an AW-IPM programme.