Movement and behavioral response of stored product insects under stored grain environments - A review

Understanding movement of insects and their behavioral response in stored grain bulks helps in controlling their infestation. Studies have been conducted on insect movement; however, determination of patterns of insect distribution is quite difficult because their behavioral responses vary with species and life stages as well as with external stimuli under different storage conditions. This review discussed insect movement, movement detection and tracing methods. Different experimental setups used for determining insect movement were presented along with their advantages and limitations with special emphasis on factors influencing insect mobility. Various model equations to predict insect movement and their spatial distribution were stated. Further, practical difficulties and challenges associated with studies of insect movement under multiple gradients were discussed. Based on literature analysis, directions for future research were presented with respect to the requirement and applicability of the emerging cost-effective technologies for insect movement detection.     

储粮害虫检测方法研究进展

科学、快速、准确进行储粮害虫检测是高效开展害虫综合防治的前提,也是保障粮食安全储藏的重要措施。本文根据国内外储粮害虫检测方法研究与应用进展情况,介绍了直观检查法、取样检查法、诱集检查法、电子检查法等储粮害虫检测方法及其优缺点,展望了储粮害虫检测技术发展方向,以期对我国储粮害虫发生的预测预报研究与应用有所裨益。     

Novel implementation of laser ablation tomography as an alternative technique to assess grain quality and internal insect development in stored products

In the last century, there have been important advances in peering inside the internal grain environment. This has included electrical conductance mills, acoustical tools, near-infrared spectroscopy, and soft X-ray imaging. Each technique has their own advantages and limitations. In this current study, we describe a novel process for assessing grain quality and internal insect development in grain using laser ablation tomography (LATscan) and compare it to soft X-ray imaging for three life stages (larva, pupa, adult) of Sitophilus zeamais and Rhyzopertha dominica. Our results suggest that X-rays overestimated grain volume loss by about a quarter compared to LATscan. Moreover, LATscan produces a rich digital dataset on the level of microns that can be explored to ask biologically-relevant questions. We discuss the current limitations of LATscan in context with other techniques. Ultimately, the results highlight LATscan as a useful additional tool to further our understanding pest-commodity interactions in the postharvest supply chain.     

储粮害虫检测技术研究进展

储粮害虫是危害粮食安全的主要因素之一,害虫检测技术对于粮食综合管理有非常重要的意义。根据国内外学者对储粮害虫检测技术的研究报道,本文归纳和总结了各种检测技术,分别介绍传统类、新型物理及生物类检测法。传统检测方法较为成熟并已被标准化,常用方法有直观检查法、取样筛检法、探管诱捕法;物理检测法较为新颖,以快速无损型检测方法为主,包括近红外及高光谱法、软X射线、电导率法、声测法、微波法、图像识别法、电子鼻等七种;生物检测法多为辅助性方法,常与其他方法联用以达到较优检测效果。本文对各种方法进行深入比较,并探讨国内外最新害虫检测技术,以期为将来研发合适的检测方法和仪器提供参考。     

混沌理论在储粮害虫预测中的应用研究展望

针对我国储粮害虫预测所面临的技术需求,分析了储粮害虫预测预报技术研究现状及其存在的问题,以研究解决储粮害虫前期预测问题为目标,围绕储粮害虫种群数量、生长规律、发生时间序列的混沌特性等进行探讨并做出展望,探索运用混沌理论中的相空间重构、庞卡莱截面、返回映像和自相关函数等方法对害虫发生非平稳时间序列进行分析和预测,将混沌理论运用于粮虫的预测预报领域,寻求储粮害虫预测技术的创新点与突破点,为储粮害虫预测预报技术提供支撑,对完善储粮害虫预测技术和保障粮食安全具有指导意义。     

基于DNA条形码技术的储粮害虫碎片鉴定研究

储粮害虫(螨)个体微小,种类繁多,与人类生活紧密相关,具有重要经济意义,储粮害虫快速鉴定是进行储粮害虫综合防治的前提和基础。传统的形态鉴定技术难以实现粮食及食品中害虫的非成虫态和碎片的准确鉴定,DNA条形码是近年来出现的物种分子鉴定技术,能够实现对昆虫非成熟虫态及碎片的快速鉴定。本研究利用DNA条形码技术和联合开发的中国储粮害虫DNA条形码鉴定系统(GPDBIS),针对某食品有限公司送检的储粮害虫碎片样品进行了序列测定、比对和分析,最终实现碎片的快速准确鉴定。结果显示,在所检测的7个害虫碎片样品中,有4头为锈赤扁谷盗Cryptolestes ferrugineus Stephens,3头为赤拟谷盗Tribolium castaneum Herbst,DNA条形码技术是储粮害虫快速准确鉴定的有效手段。     

Analysis of the relationship between type traits and functional survival in US Holstein cattle using a Weibull proportional hazards model

Survival analysis with a Weibull proportional hazards model was used to evaluate the effects of 15 linear type traits, 5 composite traits, and final score on the functional longevity of US Holstein cows. Culling data and type classification scores (measured in first lactation) from 891,524 cows with first calving from 1993 to 2000 were used. The data were divided into 9 geographical regions to determine whether the relationship between type traits and longevity differed according to climate or management system. Functional survival was defined as the number of days from first calving until culling or censoring, after correction for 305-d mature equivalent combined fat and protein yield. The Weibull model included time-dependent effects of herd-year-season, parity-stage of lactation, and within herd-year quintile ranking for combined fat and protein yield (nested within biennium), as well as time-independent effects of age at first calving and type classification score (type traits were analyzed one at a time). Type classification scores were rounded to the nearest 5 points, and the impact of each type trait on functional survival in each region was evaluated. Mean failure time ranged from 694 d in the South to 758 d in the North East. Risk of culling differed by region for several linear type traits, and differences were greatest for regions that were most dissimilar in climate and herd management (e.g., South East, East North Central, and West). Udder depth, fore udder attachment, udder cleft, and rear legs side view were consistently associated with functional longevity, regardless of region, but, the importance of some secondary traits, such as stature or dairy form, differed by region. The survival model applied in this study easily described both linear and nonlinear relationships between type traits and longevity while accounting for important time-dependent and time-independent explanatory variables.     

储粮害虫低氧应答机制的研究进展

气调储粮技术是利用低氧抑制密闭的仓储系统内生物呼吸作用的原理,达到害虫防治目的一种绿色、有效手段,然而储粮害虫较强的低氧适应能力给这项技术的实际推广带来挑战.近年来,储粮害虫低氧应答机制的研究已成为研究的热点.本文将从储粮害虫低氧适应策略及相关调控机制两方面进行综述,重点探索昆虫低氧应答调控机制,包括低氧诱导因子(HI...     

Field trials on the efficacy of Beauveria bassiana,diatomaceous earth and Imidacloprid for the protection of wheat grains from four major stored grain insect pests

We assessed the insecticidal efficacy of Beauveria bassiana, diatomaceous earth (DE) and the neonicotinoid Imidacloprid against four major insect species of stored grain pests during field trials conducted on small farms located in four districts of Punjab, Pakistan. In each district, a 40 kg lot of wheat grain was admixed with B. bassiana (3 × 10¹⁰ conidia kg⁻¹), DE (150 ppm) and Imidacloprid (5.0 ppm) alone and in different combinations. Each lot was divided subsequently into four equal parts (10 kg each), packed in polypropylene bags, artificially infested, labeled and stored at the farms under natural environmental conditions up to 6 months. Sampling was carried out every 30 d to record the total number of dead and alive adults, as well as the percent of grain damage in treated and untreated (control) grains. Results revealed a significant difference among the treatments, test insect species and the storage period. For each district, the combined treatments provided better control of all tested insect species compared with each treatment alone. The least number of surviving adults and minimum percent grain damage was observed for Imidacloprid and DE combination, but was outperformed by the DE treatment with B. bassiana for long-term protection. For all grain protectants, we obtained the same order of susceptibility level among the test species (i.e. Liposcelis paeta > Cryptolestes ferrugineus > Rhyzopertha dominica > Tribolium castaneum). The results of the present study suggested that DE, insect pathogenic fungi and Imidacloprid can be effectively used for the protection of wheat stored at small-scale farmer's fields.     

Real time monitoring of phosphine and insect mortality in different storage facilities

In this study, we evaluated wireless phosphine sensors to quantify and depict spatio-temporal dynamics and distribution of this gas within different types of facilities and commodities. The use of wireless sensors has certain advantages over the use of traditional monitoring techniques (e.g. tubes etc.), as any measurements with these traditional techniques correspond to the specific time and location of monitoring and are not transferable to additional intervals and locations, which leads fumigators to either overestimate or underestimate the concentrations and outcomes of a given fumigation. In fact, in light of our findings, the distribution of phosphine in large warehouses was not usually adequate for a satisfactory level of insect control, and gas concentrations varied remarkably through time and space. In contrast, commercial treatments at containers were sufficient to control the insects tested, even on stored-product insects which were found to be resistant to phosphine. Furthermore, in the case of silos and ship holds, our work indicated that the use of forced recirculation systems for phosphine is essential to increase concentration and, as a result, insect mortality. Overall, our tests clearly suggested that the sensors were very effective in measuring phosphine and are generally expected to play important role in the near future in IPM-based programs at the post-harvest stages of agricultural commodities. At the same time, real-time monitoring can be used with success for the prediction of insect mortality in the treated facilities.     

Prevalence and diversity of Wolbachia bacteria infecting insect pests of stored products

Wolbachia are common bacterial symbionts of insects. Because infections of these bacteria can alter the reproduction and biology of the host, there is interest in the potential use of Wolbachia to control populations of pest species. To advance this research, we screened 38 species (88 populations from 16 countries) of stored-product insect pests for Wolbachia infections. Infections were detected in nine species of Coleoptera (Anobiidae – Lasioderma serricorne (Fabricius), Stegobium paniceum (Linnaeus); Curculionidae – Sitophilus oryzae (Motschulsky), Sitophilus zeamais Motschulsky; Dermestidae – Attagenus unicolor (Brahm), Dermestes lardarius Linnaeus; Silvanidae – Oryzaephilus mercator (Fauvel), Oryzaephilus surinamensis (Linnaeus); Tenebrionidae – Tribolium confusum Jaquelin Du Val), one species of Hymenoptera (Trichogrammatidae – Trichogramma deion Pinto & Oatman), and one species of Lepidoptera (Pyralidae – Ephestia kuehniella Zeller). Phylogenetic analyses based on wsp gene sequences identified all Wolbachia isolates as members of Supergroups A or B. Additional sequences for the genes gatB, coxA, hcpA, fbpA and ftsZ were obtained for use in multilocus sequence typing (MLST) to identify the sequence types to which the isolates belonged. Our results identify five new Wolbachia-insect associations and support previous findings that infections of Wolbachia in stored-product insect pests are members of Supergroups A or B.     

Ozone fumigation of stored grain; closed-loop recirculation and the rate of ozone consumption

Research using ozone gas as a fumigant has shown promise in controlling stored-grain insect pests. In addition to being toxic to insects, ozone gas is unstable and decays naturally into diatomic oxygen and must be continually replenished to maintain entomologically lethal concentrations in the grain mass. This two-part study quantifies the rate of ozone gas decay encountered in typical grain storage environments. From this, ozone generation capacity can be modeled. A pilot study was conducted in a commercial steel grain bin filled with 13.6 tonnes of hard red winter wheat. The bin was equipped with a closed-loop recirculation system to capture and reuse ozone gas that had passed through the grain. A second laboratory study was conducted on 55 kg samples of wheat and corn to determine the rate of ozone decay in different grains at different fumigation temperatures. With previously untreated grain samples, initial ozone decay is high. After a passivation period that ranged from 53.5 to 84.7 h, the decay rate reached a steady state. The half-life of ozone ranged from 122 s in grade 4 wheat with high foreign matter content, to 242 s in grade 2 wheat. Results show that the rate of ozone decay in wheat and corn was not significantly affected by temperature in the range in which fumigations are typically undertaken.     

储粮生物危害物特征信息数据库的设计与构建

分析农业数据库研究现状及其存在的问题,在此基础上根据储粮生物危害物防治水平、储粮要求和粮仓实际情况,利用Visual Studio.NET2008和SQL Server2008构建储粮生物危害物特征信息数据库。该库系统详细收录了储粮生物危害物的相关信息等。同时还展示了系统运行界面,并对下一步的研究工作进行了分析与展望。     

Diversity and community structure of insect pests developing in stored sorghum in the Northern-Sudan ecological zone of Burkina Faso

Stored insect pests often create major problems for farmers worldwide. Comprehensive data of insect pests of stored sorghum in Burkina Faso are scarce. Understanding the population structure of insect fauna infesting stored sorghum is important for development of management strategy. Sorghum panicles were collected from January to September 2011 in farmers' granaries in the Northern-Sudanian ecological zone of Burkina Faso to determine the diversity of insect pests and their importance in post-harvest losses. A total of 14 species of insect pests were recorded, including twelve coleopteran and two lepidopteran species. Species diversity peaked between May and September. The highest insect diversity was recorded in sorghum stored in straw granaries and on red coloured grains when compared with that of sorghum stored in mud granaries and on white coloured grains. Rhyzopertha dominica (Fabricius) appears to be the primary insect pest followed by secondary pests including Oryzaephilus mercator (Fauvel), Cryptolestes ferrugineus (Stephens) and Sitophilus zeamais (Motschulsky). The distribution pattern of the pests in granaries corresponds to the Mandelbrot model in which colonization of species in an environment depends on the physical conditions of that environment and on the species currently present, which suggest a progressive colonization occurs in waves with stocks of grain.     

Assessment of quantitative and qualitative losses of stored grains due to insect infestation in Ethiopia

This study was designed to determine the quantitative and qualitative losses of stored grains that arise from insect infestation in three districts of southwestern Ethiopia. One district was selected from each zone based on the production potential of the target crops (maize, sorghum, wheat and fababean). A total of 240 farmers’ stores from all districts were randomly selected. The grain samples used in the present study were stored for 5 different time periods, ranging from 1 to 5 months and from the same farmers’ stores, to determine grain weight loss, insect damage, and nutritional losses. Grain damage showed significant differences over the storage periods across the study districts. A similar trend was observed for weight loss for each of the grains in all districts. The moisture content of the grains decreased along the storage duration. Crude protein and crude fat contents significantly decreased as the storage duration increased in all traditional storage types. Furthermore, the crude fibre and ash contents of the different grain types significantly increased as the storage duration increased in all storage types. These results demonstrated that traditional storage structures have a substantial effect on quantitative and qualitative losses of stored grains. This finding has great implications for food security and hidden nutritional deficits in society. Thus, there is a need to develop and disseminate storage technologies that minimize losses and that are affordable for small farm holders.     

华中储粮区浅圆仓储粮害虫防治技术研究

研究了在华中储粮区利用磷化氢防治浅圆仓小麦储粮害虫的效果、磷化氢气体浓度变化规律等,总结了浅圆仓储粮害虫防治的技术要点,为指导浅圆仓储粮害虫防治工作提供技术支撑。     

Heritability,reliability of genetic evaluations and response to selection in proportional hazard models

The purposes of this study were 1) to investigate the heritability, reliability, and selection response for survival traits following a Weibull frailty proportional hazard model; and 2) to examine the relationship between genetic parameters from a Weibull model, a discrete proportional hazard model, and a binary data analysis using a linear model. Both analytical methods and Monte Carlo simulations were used to achieve these aims. Data were simulated using the Weibull frailty model with two different shapes of the Weibull distribution. Breeding values of 100 unrelated sires with 50 to 100 progeny (with different levels of censoring) were generated from a normal distribution and two different sire variances. For analysis of longevity data on the discrete scale, simulated data were transformed to a discrete scale using arbitrary ends of discrete intervals of 400, 800, or 1200 d. For binary data analysis, an individual's longevity was either 0 (when longevity was less than the end of interval) or 1 (when longevity was equal or greater than the end of interval). Three different statistical models were investigated in this study: a Weibull model, a discrete-time model (a proportional hazard model assuming that the survival data are measured on a discrete scale with few classes), and a linear model based upon binary data. An alternative derivation using basic expressions of reliabilities in sire models suggests a simple equation for the heritability on the original scale (effective heritability) that is not dependent on the Weibull parameters. The predictions of reliabilities using the proposed formulae in this study are in very good agreement with reliabilities observed from simulations. In general, the estimates of reliability from either the discrete model or the binary data analysis were close to estimates from the Weibull model for a given number of uncensored records in this simplified case of a balanced design. Although selection response from the binary data analysis depends on the end of interval point, there is a relatively good agreement between selection responses in the Weibull model and the binary data analysis. In general, when the underlying survival data is from a Weibull distribution, it appears that the method of analyzing data does not greatly affect the results in terms of sire ranking or response to selection, at least for the simplified context considered in this study.     

6种储粮害虫对不同颜色的趋性研究

在实验室内利用校正趋色法,研究我国6种储粮害虫对红色等6种颜色的趋性行为反应。结果表明,6种储粮害虫对不同颜色的趋性情况大多随时间的变化而变化,在特定的时间段内,赤拟谷盗、杂拟谷盗、米象、玉米象对不同颜色的行为反应存在显著性差异(P≤0.05),其中,红色、橙色、黑色对赤拟谷盗均有明显的引诱作用,诱集率最高分别为76.23%、39.55%、49.57%;红色、黑色对玉米象有明显的引诱作用,诱集率最高分别为38.48%、38.67%。嗜卷书虱和无色书虱对所测试6种颜色则大多表现出驱避性,其中,红色和紫色分别对嗜卷书虱、无色书虱有明显的驱避作用,驱避率最高分别为70.29%、54.46%。研究结果可为研发相应颜色诱捕器对储粮害虫进行诱捕监测提供参考。     

Scrubbing carbon dioxide prevents overestimation of insect mortality in long-duration static phosphine toxicity assays

Exposing insects to toxicants such as phosphine (PH₃) in sealed chambers is a common procedure in fumigant efficacy testing. During long exposures, carbon dioxide (CO₂) produced by metabolic processes of fed insects may accumulate in the vessel. As CO₂ enhances the toxicity of several fumigants, concomitant exposure of fumigant and CO₂ may lead to erroneous measurements of insect mortality and thus fumigant toxicity. In this study, the effect of a CO₂ scrubber such as soda lime (a solid formulation of wet hydroxides of calcium, sodium and potassium) or periodic flushing of the headspace, on insect mortality in static PH₃ toxicity assays was compared with an “unscrubbed” (no intervention) treatment. Soda lime was highly effective in removing CO₂ from the headspace of sealed chambers, without measurable loss of PH₃. Mortality of Sitophilus oryzae (L.) adults treated with phosphine in chambers scrubbed with soda lime or flushed (opened) daily was considerably lower than in unscrubbed chambers. Twenty grams of soda lime per litre of exposure chamber is recommended to obtain accurate static fumigant mortality results.     

粮食储藏生理性变质研究进展

粮食是人类赖以生存的物质基础,粮食储藏变质对农业生产及食品加工影响巨大。粮食生理劣变是一个复杂、渐进的物理、化学与生物学过程,与其籽粒的生理活动密切相关。研究表明,粮食籽粒酶活性降低,呼吸作用下降,生命力减弱等是其生理变质的外在表现,储粮生理活动是引发其生理劣变的本质要素。深入了解粮食籽粒在储藏过程中生理活动及其变化规律对揭示储藏生理变质机理具有重要意义。本文主要介绍了粮食籽粒储藏衰老过程中种胚微观结构、营养物质转化、线粒体呼吸作用、细胞抗氧化系统、遗传物质变异等的研究现状,并对粮食储藏保鲜原理进行讨论,以期为提出延缓和预测粮食储藏劣变的方法提供参考。