Temperature-dependent development of Agrotis ipsilon (Lepidoptera: Noctuidae) and its stage transition models

The black cut worm Agrotis ipsilon (Hufnagel) is a destructive crop pest worldwide and a typical cut worm damaging plant parts below the soil surface, which requires a thorough phenological prediction of the target stage for proper management. Temperature is an essential factor affecting the phenology and dynamics of insect populations. So, this study was conducted to evaluate the temperature-dependent development of A. ipsilon fed on Kimchi cabbage (Brassica campestris) in a wide range of temperatures (10 to 40 ℃) in the laboratory. The linear and nonlinear relationship between temperature and development rate (1/development time) was analyzed. The lower threshold temperatures (LT) for eggs, larvae, and pupae were estimated to be 12.1 °C, 9.6 °C, and 11.2 °C, respectively, with thermal constants (degree days for development completion) of 31.3, 342.2, and 181.3 DD at each stage, respectively. Additionally, the thermal constant for tracking the phenology of each stage was determined using a common LT of 10.4 ℃: 40.3 DD for eggs, 315.6 DD for larvae, and 199.6 DD for pupae. Consequently, we provided newly the stage transition models for all stages of A. ipsilon using two basic components of the nonlinear development rate and distribution models to simulate the proportion of individuals shifted from one stage to the next stage. These models in their current form will be useful for constructing a population model for A. ipsilon in the future. Furthermore, the variation in the development time of A. ipsilon reported in previous studies was discussed using 95% confidence limits of the estimated line of our nonlinear models.

     

The sensitivity of simulation models to temperature changes1

Insect population processes, such as development and reproduction, are dependent upon temperature. Accurate predictions of the phenology and population dynamics of insect pests require accurate recording of the temperatures experienced by the organisms. Any errors in the temperature measurements may result in spurious estimates of the pest population and, therefore, poor quality advice on the necessary control strategies. A simulation model predicting the phenology and population dynamics of the summer fruit tortrix, Adoxophyes orana, will be described. Output from the model closely resembled field observations of the population dynamics of the pest. Experimentation with the model revealed its sensitivity to small changes of temperature. The results illustrate the importance of using input recorded realistically with respect to the biology of the pests.     

气候变暖对农业害虫及其天敌的影响

全球气候的持续变暖引起了人类的高度关注。农业害虫是关系到农业生产顺利进行的一个特殊的昆虫类群,已经受到温度升高的影响。本文从气候变暖对农业害虫的发生、为害以及与天敌间关系的影响等三方面进行了综述。温度升高导致农业害虫的发生区域扩张,发生期提前和延长,高温适生种群发生量增大;农业害虫的为害时期改变,为害程度加重,为害物种之间产生新的竞争关系;农业害虫与寄主植物、天敌之间的同步性发生改变,继而影响到农业害虫的生物防治。本文最后对当前的研究工作进行了评述,就气候变暖形势下农业害虫的防治提出建议。     

Phenology modelling of major insect pests in fruit orchards from biological basics to decision support: the forecasting tool SOPRA*

The forecasting tool SOPRA has been developed with the objective of optimizing timing of monitoring, management and control measures of insect pests in fruit orchards in Switzerland. Applying time‐varying distributed delay approaches, phenology‐models were developed driven by solar radiation, air temperature and soil temperature on hourly basis. Relationships between temperature and stage‐specific development rates for relevant stages of the life cycles were established under controlled laboratory conditions for Dysaphis plantaginea, Hoplocampa testudinea, Cydia pomonella, Grapholita lobarzewskii, Cacopsylla pyri, Rhagoletis cerasi, Anthonomus pomorum and Adoxophyes orana. The implementation of body temperatures in the models is based on habitat selection and biophysical modelling of habitat conditions. In order to validate modelling, phenology predictions were compared with several years of independent field observations. On the basis of local weather data, the age structure of the pest populations is simulated and crucial events for management activities are announced. Through a web interface, the simulation results are made available to consultants and growers ( http://www.sopra.info ) and the latter can be applied as a decision support system for the eight major insect pests of fruit orchards in the alpine valleys and north of the Alps on local and regional scale.     

Using phenology prediction in weed management: a review

The success of weed management based on ecological principles and weed biology will depend on a better understanding of the effect of environment on lift history strategies, growth, and competition of weeds; and crops, and particularly upon the ability to predict weed and crop phenology, This paper reviews the importance of phenotypic plasticity to weed and crop competition and other biological interactions. We also discuss the utility of phenological predictions in weed management and review current weed phenology models that are based on thermal time. By understanding the variables that drive plant phenotypic responses, new approaches and more long-term solutions for weed problems can be developed.     

Modelling the interactions between phenology and insecticide resistance genes in the codling moth Cydia pomonella

In the codling moth Cydia pomonella (L), insecticide resistance genes have been associated with pleiotropic effects affecting phenology. In this paper, we investigated whether an increase in the frequency of insecticide resistance in field populations of C pomonella was likely to entail significant divergences in the temporal occurrence of both susceptible and insecticide-resistant individuals. For this purpose, we built a phenological model that provided suitable predictions of the distinct and diverging seasonal evolutions of populations of a susceptible and two insecticide-resistant (at two and three loci) homozygous genotypes of C pomonella. Model simulations for each genotype were further compared with pheromone trap catches recorded in a field insecticide-treated population over an 8-year period (from 1992 to 2000), which reflected the progressive annual increase in the frequency of resistance in southeastern France. We found a significant delay in field adult emergence relative to those predicted by the homozygous susceptible model, and the magnitude of such a delay was positively correlated with increasing frequencies of insecticide resistance in the sampled field population of C pomonella. Adult emergence predicted in the theoretical population that was homozygous for resistance at two loci converged with those recorded in the field during the investigated 8-year period. This suggested that the pleiotropic effects of resistance were likely to result in a significant phenological segregation of insecticide-resistant alleles in the field. The results of this study emphasized the potential for pest populations exposed to chemical selection to evolve qualitatively with respect to phenology. This may raise critical questions regarding the use of phenological modelling as a forecasting tool for appropriate resistance management strategies that would take into account the diverging seasonal evolutions of both insecticide resistance and susceptibility.     

Required number of location-years for estimating functional lower developmental thresholds and required thermal summations of insects: The first emergence of adult Apthona nigriscutis Foudras as an example

Sampling theory was combined with resampling techniques to determine the number of location-years needed for estimating an insect's required thermal summation and lower developmental threshold from field-based studies. This was done by analysing 19 location-years of field observations on the first emergence of Apthona nigriscutis Foudras, an important biological control agent of the noxious weed, leafy spurge (Euphorbia esula L.). Results indicated that 5 - 7 location-years were needed to estimate that insect's mean required thermal summation and mean lower developmental threshold for predicting first adult emergence. However, if the wish was to estimate the median required thermal summation and median lower developmental threshold for that purpose, then 8 - 11 location-years were needed to obtain acceptable estimates of those parameters. The implications of these and other findings are discussed.     

DYMEX模型在棉铃虫种群动态中的应用

模型模拟是昆虫种群动态研究的重要内容,DYMEX模型是一种基于同生群概念的机理性模型,能够较真实、全面地模拟多因素影响下的种群动态,便于推广应用。棉铃虫Helicoverpa armigera自然种群动态受到诸多生态因子的影响,如气候、天敌和田间管理等,过程复杂。本文利用DYMEX 3.0软件建立了棉铃虫种群动态模型,对实验室棉铃虫种群关键生命表参数随温度变化和控制条件下杀虫剂对棉铃虫和天敌的毒杀作用分别进行了模拟;对新疆石河子121团和147团2009-2014年棉铃虫自然种群动态进行了模拟,并比较和分析了模拟结果。结果表明:(1)建立的棉铃虫DYMEX模型,在模拟实验室棉铃虫种群各阶段发育历期、存活率、成虫繁殖和寿命,以及杀虫剂对棉铃虫卵、1~3龄幼虫和天敌的毒杀影响方面,拟合优度R~2普遍高于0.6(P0.05);(2)模拟田间条件下棉铃虫种群的相对发生量和发生期与实际自然种群具有较好的一致性。因此,建立的DYMEX模型,较可靠地模拟、反映了室内控制条件和复杂生境下棉铃虫种群特征和动态,为棉铃虫室内多因素试验结果分析、因素效能分析和复杂条件下发生期和相对发生量的预测预报等方面提供有效帮助,为田间害虫的综合管理、防治提供参考。     

Management of Stored Wheat Insect Pests in the USA

Management of stored-grain insect pests by farmers or elevator managers should be based upon a knowledge of the grain storage environment and the ecology of insect pests. Grain storage facilities and practices, geographical location, government policies, and marketing demands for grain quality are discussed as factors influencing stored-grain insect pest management decisions in the United States. Typical practices include a small number of grain samples designed to provide grain quality information for segregation, blending and marketing. This low sampling rate results in subjective evaluation and inconsistent penalties for insect-related quality factors. Information on the efficacy of insect pest management practices in the United States, mainly for farm-stored wheat, is discussed, and stored-grain integrated pest management (IPM) is compared to field-crop IPM. The transition from traditional stored-grain insect pest control to IPM will require greater emphasis on sampling to estimate insect densities, the development of sound economic thresholds and decision-making strategies, more selective use of pesticides, and greater use of nonchemical methods such as aeration. New developments in insect monitoring, predictive computer models, grain cooling by aeration, biological control, and fumigation are reviewed, their potential for improving insect pest management is discussed, and future research needs are examined.     

农业害虫高温调控的研究进展

利用高温控制害虫具有无残留、无污染的优点,高温对害虫的致死作用在害虫种群生态调控研究和保证食品安全,促进绿色农产品生产中有潜在的应用价值。本文综述了国内外影响高温对昆虫致死效应的因子和应用高温防治害虫的技术方法。影响高温致死效率的因子包括:温度的高低和处理时间的长短,不同温度的处理顺序和预适应温度等温度处理模式,缺氧等逆境胁迫,昆虫种类及其发育阶段等。利用高温防治害虫的技术包括:温室内,在生长期采用高温闷棚,在播前产后用热蒸汽处理苗床或培养土。在田间,利用对作物安全的瞬间明火烧伤害虫敏感部位;利用害虫的趋光性点明火诱杀;作物生产空闲期采取覆膜封闭,利用太阳能产生高温、缺氧条件,减少或根除土传病菌和害虫。在仓库,利用微波、无线射频或流动床产生的热空气在短时间内升温,杀死储粮害虫。在储运场所,用热水浸泡、热蒸汽熏蒸、高温结合低氧或低温以及盐水浴结合无线射频处理鲜活农产品,杀死害虫。本文最后讨论了该领域存在的问题,指出阐明高温对昆虫影响的机理,降低防治成本,减轻作物和环境损害,是高温控制害虫技术推广应用的关键。     

Thermal effects on the development of <Emphasis Type="Italic">Bactrocera dorsalis</Emphasis> (Hendel) (Diptera: Tephritidae) and model validation in Taiwan

The oriental fruit fly, Bactrocera dorsalis (Hendel), is a major polyphagous insect pest with a worldwide distribution. The effects of temperature on stage-specific development in B. dorsalis were investigated at eight constant temperatures (13.0 °C, 14.4 °C, 16.2 °C, 19.5 °C, 23.8 °C, 27.7 °C, 31.8 °C and 34.8 °C). B. dorsalis developed successfully from the egg stage to the adult stage at all the tested temperatures, except at the lowest temperatures (13.0 °C and 14.4 °C). Stage-specific lower developmental thresholds and thermal constants were determined using linear regression. The lower and higher temperature threshold (TL and TH, respectively) were estimated using the Sharpe-Schoolfield-Ikemoto model. The lower developmental threshold and thermal constant from egg to adult emergence were 9.8 °C and 325.5 degree-days, respectively. The intrinsic optimum temperatures of the egg, larval, pupal and egg to pupal stage were 20.7 °C, 21.8 °C, 21.1 °C, and 22.4 °C, respectively. The temperature range of the B. dorsalis total immature stage from TL to TH was 20.4 °C (13.8 °C - 34.2 °C). The stage-specific developmental completion of B. dorsalis was determined using a two-parameter Weibull function. The daily adult emergence frequency of B. dorsalis was estimated in relation to adult age and temperature using non-linear developmental rate functions and the Weibull function. The date of cumulative 50% adult emergence estimated using non-linear functions was approximately one day earlier than the experimentally observed date. Thermal performance was compared among B. dorsalis populations from different locations.     

Monitoring the appearance and possibility for prevention of the apple sawfly in Croatia

The apple sawfly Hoplocampa testudinea Klug has recently become a widespread pest in Croatian apple orchards. It causes severe damage in the blooming period due to the fact that infested fruit fall off.This article shows results collected over three years of field research on trap catches of sawflies, the period of laying eggs, the appearance of larvae and detection of damage. In the climate of northwestern Croatia, adult sawfly appear in April during the blooming period of the early apple variety of Idared.By monitoring temperatures from January 1, adults were detected when the thermal constant reached 210 day-degrees. Our observations showed that the larvae emerged when the sum of thermal constants reached ca. 110 day-degrees.The investigation of effective control strategies with insecticides showed high efficacy of thiametoxam (Actara), imidacloprid (Confidor), thiacloprid (Calypso) and betacyfluthrin + oxydemeton-methyl (Enduro) and lower efficacy of phosalone (Zolone), chlorpyrifos-methyl (Reldan), and lambda cyhalothrin (Karate).     

Agricultural insect hybridization and implications for pest management

Biological invasions, the expansion of agricultural frontiers, and climate change favor encounters of divergent lineages of animals and plants, increasing the likelihood of hybridization. However, hybridization of insect species and its consequences for agroecosystems have not received sufficient attention. Gene exchange between distinct and distant genetic pools can improve the survival and reproduction of insect pests, and threaten beneficial insects in disturbed agricultural environments. Hybridization may be the underlying explanation for the recurrent pest outbreaks and control failures in putative hybrid zones, as suspected for bollworm, corn borer, whiteflies, and stink bugs. Reliable predictions of the types of changes that can be expected in pest insect genomes and fitness, and of their impacts on the fate of species and populations remain elusive. Typical steps in pest management, such as insect identification, pest monitoring, and control are likely affected by gene flow and adaptive introgression mediated by hybridization, and we do not have ways to respond to or mitigate the problem. To address the adverse effects of farming intensification and global trade, we must ensure that current integrated pest management programs incorporate up‐to‐date monitoring and diagnostic tools. The rapid identification of hybrids, quantification of levels of introgression, and in‐depth knowledge of what genes have been transferred may help to explain and predict insect population outbreaks and control failures in the future. © 2019 Society of Chemical Industry     

More accurate measurement of temperature in potato drills increases predicted potato cyst nematode population growth

Potato cyst nematodes (PCN) are economically important pests of potato plants worldwide that can result in yield losses exceeding 80%, with an estimated cost of £50 million annually in the United Kingdom alone. The life cycle of PCN, and in particular the hatching of eggs and development and survival of juveniles, is sensitive to temperatures in the soil. Despite this fact, relatively little is known about temperatures inside potato drills and how these may differ to temperatures in the surrounding soil. We monitored the temperature inside potato drills at 19 sites across the United Kingdom and used a published temperature-driven process-based PCN life cycle model to compare predictions of PCN population dynamics driven by these temperatures to predictions based on modelled soil temperatures derived from the HadUK-Grid climate. We found that mean soil temperatures derived from the climate model were lower than those observed inside potato drills; thus, using temperatures measured directly in potato drills resulted in increased estimates of population growth and shorter estimated generation times than when using modelled soil temperatures. This finding suggests that greater understanding of the temperature inside potato drills is required if we are to make accurate predictions about the effects of temperature on PCN populations.     

Potential manageable exploitation of social wasps,Vespula spp. (Hymenoptera: Vespidae), as generalist predators of insect pests

A manageable, generalist, predatory insect has to date been considered to be unavailable anywhere for pest insect control. Polistes spp. wasps showed promise, but are limited by small numbers of wasps per nest and short nest life. Social Vespula spp. wasps appear to possess the necessary attributes which will allow their development as manageable, generalist predators of a wide range of pest insects. They have a large number of foragers per nest, a high demand for invertebrate protein, a very wide range of prey, an ability to tolerate low temperatures, a tolerance of nest manipulation, and a colony life cycle that can span at least two summers. High numbers per nest and high nest densities can lead to the consumption of many kilograms of prey per hectare per year. Successful development of characteristics desired of a manageable predator, such as the ability to increase colony numbers by dividing and re-queening, and enhancement of multi-year colony existence, could result in management procedures for Vespula spp. wasps that are similar to those used for honey bees. Farmers could have wasp nests available when and where required and in the numbers desired. Wasps would be especially valuable for growers of some ‘organic’ crops in which conventional pesticides are not permitted.     

Current status of the rice water weevil Lissorhoptrus oryzophilus in Italy: eleven‐year invasion

The rice water weevil Lissorhoptrus oryzophilus (Coleoptera: Curculionidae: Brachycerinae) was detected in Northern Italy in 2004. As Italy is the major European rice producer, and the rice water weevil is considered to be one of the major pests of rice in the world, a multiyear study was carried out to determine the spread of the pest in Northern Italy, to evaluate its establishment potential and to improve the knowledge on its biology in this new habitat. The survey allowed the distribution of the insect in Italian rice areas to be evaluated and confirmed that L. oryzophilus behaves as a monovoltine parthenogenetic species in Northern Italy. Information about the phenology of the insect and its management are also provided.     

田间背景气味对植物源引诱剂的干扰及相应研发策略

植物挥发物在害虫的寄主选择过程中发挥着重要作用。植物源引诱剂是一类重要的害虫绿色防控产品，也是目前害虫无害化防治的研究热点。但目前大多数研究还未达到田间可应用的程度。其主要原因是田间引诱效率不理想。已有研究显示田间背景气味可干扰昆虫的嗅觉定向，干扰植物源引诱剂的引诱效率。因此对以往忽略的田间背景气味干扰加以重视，可进一步加快植物源引诱剂的研发进程。本文从气味传播与昆虫嗅觉感知、背景气味干扰嗅觉定向、田间背景气味复杂性和其对引诱剂的干扰等方面进行了综述与探讨，并对引诱剂配方组配过程中如何降低田间背景气味的干扰提出了相应的研发策略，以期促进植物源引诱剂的创新发展。     

Natural products for pest control: an analysis of their role,value and future

Natural products (NPs) have long been used as pesticides and have broadly served as a source of inspiration for a great many commercial synthetic organic fungicides, herbicides and insecticides that are in the market today. In light of the continuing need for new tools to address an ever‐changing array of fungal, weed and insect pests, NPs continue to be a source of models and templates for the development of new pest control agents. Interestingly, an examination of the literature suggests that NP models exist for many of the pest control agents that were discovered by other means, suggesting that, had circumstances been different, these NPs could have served as inspiration for the discovery of a great many more of today's pest control agents. Here, an attempt is made to answer questions regarding the existence of an NP model for existing classes of pesticides and what is needed for the discovery of new NPs and NP models for pest control agents. © 2014 Society of Chemical Industry     

欧洲向日葵螟发育有效积温及其成虫发生预测模型研究

为了明确欧洲向日葵螟的发生时期与气温的关系,根据有效积温对该虫的发生时间进行预测,在4个不同温度条件下(24、27、30、33℃)测定了欧洲向日葵螟各虫态的发育历期,利用最小二乘法计算出各虫态的发育起点温度和有效积温;并结合2009-2014年间巴彦淖尔市欧洲向日葵螟监测点的监测结果及当地气象数据,对欧洲向日葵螟成虫发生动态与有效积温的关系进行曲线拟合。结果显示,欧洲向日葵螟卵、幼虫、预蛹以及蛹4个虫态的发育起点温度分别为14.31、8.07、18.27、12.2℃,发育所需有效积温分别为45.13、328.42、12.97、140.54日·度。随着田间有效积温的上升,成虫累积捕获比例呈现两次明显的Logistic增长。研究分别构建了不同世代的成虫累积捕获比例增长曲线模型。上述研究结果可为以后欧洲向日葵螟的监测及防治工作提供科学参考。     

Phaenologische waarnemingen omtrent de koolgalmug (Contarinia nasturtii Kieff.)

Summary Control measures against insect pests are only successful if application takes place on the right point of time. To fix this point it is very important to know the dates of appearance of the various stages of the injurious insect. Leefmans obtained these phenological dates in 1936 for the control of the swede midge by using various types of emergence cages. He discussed the merits and disadvantages (1953) and constructed a new system, consisting of seven uncovered wooden emergence cages with one changing, free lid.All metal conical traps (v. Dinther, 1953) proved to be very useful in the study of asparagus fly and carrot fly.The eggs of the swede midge can be recognised in the field after a special training, and then emergence cages are needless. The problem, however, is when to start looking for eggs by examining the cabbage plants in the field. Therefore a survey is given of the results of thirteen years of phenological observations on the swede midge with emergence cages on several places in the Netherlands.It shows that the first appearance of the swede midge can be expected in the last decade of may; in most cases however the first midges appeared in the first half of june.