Estimation of area under the disease progress curves in a rice-blast pathosystem from two data points

Attempts were made to estimate the area under the disease progress curve (AUDPC) of rice blast disease caused by Pyricularia grisea from two data points on the disease progress curve. Forty-two rice genotypes were exposed to high disease pressure in a nursery over nine seasons. A conducive condition was created for maximum disease development through high nitrogen application, close spacing and maintenance of high relative humidity. Disease severity was recorded on alternate days beginning from disease initiation until the end of the epidemic. The estimation of AUDPC, and logistic and Gompertz apparent infection rates using either all-points (AP) or two-point (TP) methods revealed significant correlations among them. This was also confirmed through regression analysis and factor analysis. Hence, the estimation of AUDPC from two data points i.e. initial and final disease scores of the disease progress curves is recommended as providing information similar to that from all the data points; this should save valuable time, labour and economic resources.     

Angular leaf spot of phaseolus beans: relationships between disease, healthy leaf area, and yield

ABSTRACT Five field experiments were conducted to investigate the relationship between the severity of visible disease (X), area under the disease progress curve (AUDPC), healthy leaf area index on any given day (HLAI), radiation intercepted by healthy leaf area on any given day (HRI), healthy leaf area duration (HAD), total healthy leaf area absorption (HAA), and yield of Phaseolus beans, cultivars Rosinha and Carioca, inoculated with Phaeoisariopsis griseola at several doses. In general, yield was not related to disease severity (X) or AUDPC. In contrast, the highest yields were always related to the highest values of HAD and HAA. The relationship between yield and HAD was linear in each of five trials (29.9 < R(2) < 70.2%, P < 0.001). The relationship between yield and HAA was linear in four of the trials (52.3 < R(2) < 70.3%, P < 0.001) and exponential in one of them (in which the plant canopy was the largest). Singlepoint models using HRI to estimate yield at various times during the crop season were developed. The slope of the yield-HRI relationship proved to be stable (26.8 +/-2.4 g MJ(-1)), regardless of cultivar, locale, planting date, and bean growth stage (from R5 to R8). The yield-HLAI relationship proved to be less consistent. HRI is proposed as a key explanatory variable for a transportable system of disease management; it may be useful in producing precise recommendations at the farm level.     

载药明胶微球剂的制备及应用研究进展

微球剂(microspheres)是指活性成分溶解或均匀分散在辅料(包括载体)中形成的微小球状实体(粒径一般在1～250μm之间).天然高分子明胶因具有无毒无害、来源丰富、生物可降解等特点已成为控释剂的理想载体,在生物、医学及农药等领域展现出良好的应用前景.本文重点论述了以明胶为载体,负载农药(医药)后形成微球剂的制备...     

水杨酸不同施用方式对诱导烟草抗病性的影响

本研究比较了以0.25、0.50和0.75mol/L水杨酸(SA)进行喷施、穿刺和化学农药防治烟草病害对田间烟草抗病性的影响。结果表明:外源喷施SA和吸附SA插签两种给药方式均能诱导烟草产生对烟草番茄斑萎病、黑胫病、普通花叶病、野火病和赤星病的抗性。SA诱导的抗性具有广谱性,且防效随着施用浓度的增加而增加,在0.75mol/L时达到最大。相同浓度下,SA穿刺处理对烟草的抗性诱导较喷施处理更佳。处理后,随时间的推移,喷施SA处理抗性诱导呈逐渐降低的趋势,而SA穿刺处理,对烟株的抗性诱导作用在处理后第20~30天达到最大,在后期对烟草番茄斑萎病、野火病以及赤星病的抗性诱导作用显著高于对照(P0.05)。综合分析表明,SA穿刺施药技术对烟株病害具有广谱性、持久性以及安全性等特点,能保持高抗性诱导作用40d以上,并能有效减少农药使用量和次数,降低烟叶原料农药残留,具有较好的推广应用价值。     

气候变化背景下橡胶树白根病在全球的适生区预测

为明确橡胶树白根病在全球的适生区潜在分布,探究未来气候变化背景下该病适生区的时空变化趋势.本研究利用基准时段(1970年-2000年)和未来(2041年-2080年)的全球生物气候数据和该病地理分布信息,基于最大熵模型预测未来该病适生区分布.结果表明:模型训练集和测试集受试者工作特征曲线下方面积值分别为96.5％、94...     

昆虫性信息素研究进展与应用前景

昆虫性信息素是由性成熟的个体产生和释放,能引诱或激起同种异性个体进行交尾的微量化学物质。由于昆虫性信息素具有微量、高效、灵敏度高、对天敌无害、对环境友好等特点,目前已广泛应用于虫情监测、干扰交配、害虫检疫及大量诱杀等方面。近年来,随着性信息素分析技术的改进,检测仪器的多样及灵敏度的提高,针对昆虫性信息素的研究不断拓展和深化。本文在广泛调研国内外大量文献的基础上,综述了昆虫性信息素的生物学研究概况、性信息素的结构特点、提取方法、鉴定方法、化学合成以及其在调控害虫行为方面的应用等领域的研究进展,并对其应用前景进行了展望,旨在为昆虫性信息素的研发与应用提供技术参考和理论依据。     

Characterization of Heterodera carotae from the Tarlton area,South Africa,and determination of its life cycle under field conditions: a baseline study

Journal of Plant Diseases and Protection - Identification of Heterodera carotae (carrot cyst nematode), first reported from the Tarlton area in South Africa in 2008, was based on morphometrical and...     

昆虫共生微生物在病虫害防治的研究进展

昆虫体内的共生微生物是一大类生物群体,包括细菌、真菌、病毒及一些小型原生生物,它们广泛分布于昆虫体内,具有参与昆虫体内合成氨基酸、维生素等小分子营养物质,分解纤维素等大分子化合物,以及降解杀虫剂和植物次生代谢物等作用。此外,也能间接调控宿主生物的免疫系统,从而阻断病原体的复制和传播。因此,在害虫防治和控制虫媒病毒传播等方面具有应用潜力。该文综述昆虫共生微生物在病虫害防治方面的最新研究进展,探讨其生物学功能、与宿主的作用机制、宿主对病原微生物的适应机制以及在病虫害防治中应用等方面的研究进展,并对未来发展趋势及在害虫防治方面的应用前景进行展望。     

Anthracnose on almond in Australia:disease progress and inoculum sources of Colletotrichum acutatum

Anthracnose, caused by Colletotrichum acutatum, is an important disease of almond and has caused significant economic losses in California, Israel and Australia. Anthracnose development was monitored for three growing seasons in an almond orchard in South Australia on two almond cultivars, Price and Nonpareil, with up to 80 % of fruit affected in 2004. Lesions, typical of anthracnose, formed on young developing fruit and symptoms continued to appear until the fruit were ca 20 mm long, after which no further lesions developed. Symptoms were observed on leaves, woody tissue showed signs of dieback, but blossom blight was not observed. Maximum disease incidenceperfor, man and Relative Area Under the Disease Progress Curve (RAUDPC) were significantly larger for Price than Nonpareil for each season, but differences in the apparent rates of infection for both cultivars were insignificant for the three growing seasons. The apparent rates of infection were correlated with rainfall and daily temperature for the three years combined but there was no correlation between maximum disease incidence or RAUDPC and these environmental parameters. Considerably more mummified fruit remained on the trees of cv. Price than Nonpareil each year; however, there was no correlation between the number of mummified fruit in one season and maximum disease incidence, RAUDPC or apparent rate of infection, in the following season. C. acutatum was recovered from mummified fruit, peduncles and bark, from both Price and Nonpareil, every month throughout a year-long sampling period. C. acutatum was also recovered from asymptomatic leaves, fruit, bark, buds and blossom, however, less frequently and at lower rates than from mummified fruit and peduncles. Recovery was consistently greater from Price than from Nonpareil for all tissues.     

Genetic variation in partial resistance to leaf rust in winter wheat: disease progress,foliage senescence and yield reduction

Relations between leaf rust progress, foliage senescence and yield reduction were studied for seven winter wheat genotypes, differing in their partial resistance to leaf rust. Leaf rust accelerated leaf and ear senescence. Photosynthesis measurements showed, however, that the photosynthetic capacity of the remaining green surface was not affected. Differences between genotypes in yield reduction were largely explained by differences in leaf senescence and, therefore, in cumulative light interception (r=0.83) and crop photosynthesis. Reduction in cumulative light interception was closely related to the area under the disease-progress-curve (r=0.85), which was also closely associated with yield reduction (r=0.88). However, the time taken to reach a 50% reduction of green leaf area and the pustule density on 1 July (i.e. halfway through the epidemic) were just as good predictors of yield reduction as cumulative light interception and area under disease-progress-curve, suggesting that the former are useful criteria in the selection for partial resistance to leaf rust.Samenvatting De relatie stussen de epidemiologie van bruine roest, bladveroudering en oprengstderving werden bestudeerd bij zeven wintertarwegenotypen die verschilden in partiële resistentie tegen bruine roest. Bruine roest versnelde de veroudering van blad en aar. Fotosynthesemetingen wezen echter uit dat de fotosynthesecapaciteit van het resterende groene oppervlak niet werd beïnvloed. Verschillen tussen de genotypen in opbrengstderving werden voornamelijk veroorzaakt door verschillen in bladveroudering en daarmee in cumulatieve lichtinterceptie (r=0.83) en gewasfotosynthese. De reductie in cumulatieve lichtinterceptie was nauw gerelateerd aan de cumulatieve ziektedruk (in puistdagen) (r=0.85), welke ook nauw was geassocieerd met de opbrengstderving (r=0.88). De opbrengstreductie werd echter even goed voorspeld door de tijdsduur tot 50% reductie van het groene bladoppervlak en de puistdichtheid halverwege de epidemie als door cumulatieve lichtinterceptie en cumulatieve ziektedruk, waardoor beide eerste criteria gebruikt kunnen worden in de selectie voor partiële resistentie tegen bruine roest.     

Heterogeneity of peach rust disease progress within the tree canopy

Peach rust (Tranzschelia discolor) is a major foliar disease of peach that can cause severe defoliation. Few epidemiological studies have been conducted on peach rust, and there is no information concerning the spatial distribution of the disease within the canopy. This study aimed to characterise the onset and temporal progress of peach rust in three height strata in peach trees grown in two different orchards: one treated with fungicide and the second non-treated. Evaluations were conducted fortnightly between November and April for two consecutive years. Positional information for the disease within the canopy was obtained by assessing the incidence and severity of peach rust on leaves in both orchards. A linear mixed model with the position of shoots as the fixed effect and cultivars and blocks as random effects was adopted for the data analysis over both seasons, in the fungicide-treated orchard incidence and severity ranged from 60 to 90 % and 0.5 to 2 %, respectively, while in the non-treated orchard incidence and severity ranged from 90 to 100 % and 10 to 15 %, respectively. The area under the disease progress curve was greater for the upper shoots compared to the lower shoots, but the disease progress rates were similar. The logistic and exponential models best fitted the incidence and severity data, respectively. Urediniospores were detected by traps within the experimental area between late winter and early spring. Predominance of autoinfection or alloinfection is discussed.     

The relationship of leaf wetness duration and disease progress of glume blotch,caused byStagonospora nodorum,in winter wheat to standard weather data

Almost 50% of the variation in leaf wetness duration can be explained by maximum and minimum temperatures, rainfall and hours with relative humidity above 90% on a daily basis. All of these parameters can be estimated from a standard weather station. If variables related to wind are added the level of explanation increases to 69–76%. Leaf wetness duration explained up to 42% of the rate of disease increase (RDI) forS. nodorum. Leaf wetness duration was accumulated over a 5-day window period and correlated with rate of disease increase after a 7-day lag period. Standard weather variables could explain 20–34% of the disease increase. The relevance of these statistical models to disease prediction is discussed.     

主要栽培管理措施与黄淮区水稻黑条矮缩病发生的关系

为探明栽培管理措施与黄淮区水稻黑条矮缩病发生的关系,采用田间实地调查法研究了灌水、施氮、落谷密度和防虫网处理对水稻黑条矮缩病发生的影响,并对黄淮区主要水稻品种进行抗（耐）病筛选。结果表明,秧田期减小落谷量和施氮量,发病率最高可分别降低78.5%和77.7%;水稻抽穗前采用浅湿灌溉与深水处理相比,发病率最高可降低70.3%;秧田期防虫网处理与无防虫网相比,发病率最高可降低87.6%;分蘖期不施氮肥处理较过量施氮发病率最高可降低83.5%。黄淮区主要品种抗（耐）病性存在显著差异,抗病和产量性状都较好的品种为新稻20和苏秀10号,而金粳18可能对该病具有较强的耐害性。因此,在黄淮稻区,采用浅湿灌溉方式,适当减少施氮量和落谷量,秧田期采用防虫网处理,并选择抗（耐）病品种,可减轻黑条矮缩病对水稻生产的危害。     

喷雾助剂对茎叶处理除草剂的增效机制及应用研究进展

农田草害的发生严重影响了农业生产和发展,使用除草剂进行化学防治是目前最省时省力和防除效果最好的除草方法.其中,茎叶处理除草剂因其具有不受土壤环境影响、按草施药、灵活和选择性高等优点,应用范围更广.然而,茎叶处理除草剂在喷雾施药过程中由于受到杂草叶片界面特性的影响,常出现药液迸溅、滚落、难以渗透等现象,导致除草剂用量增大...     

磁环境条件下番茄抗逆性的初探

盆栽试验模拟磁环境条件下番茄的抗逆性（主要抗旱性和抗病性）研究得出，番茄在磁环境条件下，叶细胞膜相对透性、伤害率均小于对照（CK）处理，且随着磁环境强度增加，叶细胞膜相对透性、伤害率降低，表明在磁环境条件下生长的番茄有较强的抵抗干旱的能力；在磁环境条件下生长的番茄，在其营养生长期间，抗病性明显增强，且随磁环境强度增加，抗病性呈逐渐增强的趋势，并与过氧化物酶活性有一定相关性，可促进植株木质化程度。磁环境条件下可通过活化酶调节基因，控制过氧化物酶活性，从而提高番茄的抗病能力。     

我国苹果主要病害研究进展与病害防治中的问题

苹果是重要的经济作物,2012年中国的栽培面积已超过200万hm2。在苹果的高产优质栽培中,病害成为制约产业发展的重要因子。腐烂病仍是苹果树上的第一大病害,目前正面临第5次大流行的威胁;苹果实施套袋栽培措施后,枝干轮纹病逐年加重,在环渤海湾和黄河故道苹果产区部分果园的危害已超过腐烂病;褐斑病在西北黄土高原苹果产区每年都造成严重落叶;随着城市和道路的绿化,苹果锈病的危害逐年加重,成为部分果园每年必防的病害;病毒病有进一步扩展蔓延的趋势,正严重威胁着新建果园;“黑点病”是自苹果套袋后新出现的一种病害,每年造成的产量损失约为5%~30%;炭疽叶枯病是2011年在我国新发现病害,正威胁着‘嘎啦’、‘金冠’、‘秦冠’等品种的栽培;苹果疫腐病、炭疽病、霉心病、斑点落叶病、白粉病、褐腐病等病害偶有暴发,生产中不可忽视。本文从病害管理角度出发,回顾了近年来,尤其是成立农业产业体系以后,苹果病害研究方面的进展,分析了病害管理中存在的问题,以促苹果病害管理水平的提高。     

施钾对旱地豌豆产量、水分效应及土壤钾素的影响

2006年在陇中黄绵土上进行的钾肥肥效试验表明:黄绵土已出现钾素亏缺,施用钾肥能显著增加豌豆的耗水量,增大叶面积、单株节数、结荚数和单株豆粒数,增加了千粒重,从而提高了产量、经济系数、耗水量和水分利用率.与对照相比,其中施纯K2037.5 kg/hm2时,豌豆增产最大,增产26.7%,耗水量最大,增加14.5%,水分利用效率增加10.5%,经济系数提高17.2%.并建立了陇中地区钾肥适宜施用量与豌豆产量的数学模型y=0.0006x3-0.1576x2 10.973x 895.91,当钾肥施用量达到43.4 kg/hm2时,经济效益最高.施钾能增加土壤速效钾含量和植株全钾含量.     

有机氯类禁限用农药抗体的制备和应用研究进展

农药在防治病虫害、提高农产品产量和质量方面效果显著,但一些农药因高毒、致癌、致畸、致突变、代谢缓慢,对人类和环境产生不利影响而被我国禁止或限制使用。有机氯类禁限用农药作为其中产量最多、用量最大的一类,存在较高的健康或环境风险而备受关注。建立高效便捷的有机氯类禁限用农药残留的检测方法,对确保食品安全、助力绿色生态农业发展、打破食品进出口技术贸易壁垒具有重要意义。免疫分析法以其快速、简便、灵敏等优势被广泛应用于食品中农药残留的检测。本文综述了有机氯类禁限用农药免疫检测方法的研究进展,介绍了半抗原的合成和抗体的制备,总结了抗体在免疫检测中的应用,主要包括酶联免疫分析法、免疫层析试纸条法、化学发光法、荧光免疫分析法和免疫传感器,可对未来有机氯类禁限用农药免疫分析法的进一步研究开发提供参考。     

基于风蚀模型的准东地区土壤风蚀研究

文中选取准噶尔盆地东部(准东)为研究区,以土地利用类型、气象数据为基础,结合实地监测与调查,基于中科院寒区旱区环境与工程研究所的大田推广模型,定量计算各类地表在不同植被和风力条件下的土壤风蚀模数,分析准东地区土壤风蚀状况。结果表明:准东地区土壤风蚀模数呈现未利用地(风蚀模数6456.17t·km~(-2)·a~(-1))>林草地(风蚀模数3437.32t·km~(-2)·a~(-1))>耕地(风蚀模数758.71t·km~(-2)·a~(-1));土壤风蚀主要发生月份为4月和5月,占全年风蚀量的52%。模型模拟的准东地区年风蚀总量达10194.28万t,平均风蚀模数4571.43t·km~(-2)·a~(-1)。为验证模型模拟的准确性,用测钎法实测准东地区土壤风蚀模数,模型模拟值与实测之间的误差分析表明模型的精确性达84%以上,证明该模型可用于该区域土壤风蚀监测。     

我国病毒杀虫剂研究与应用新进展

由于化学农药的大量使用对环境生态造成的严重影响，我国政府已把保护环境、食品安全摆到了重要的议事日程。昆虫病毒杀虫剂作为生物防治的重要手段之一，其优点在于特异性强、毒力高、稳定性好、安全无害，用后能引起害虫群体病毒疾病的流行传播，在相当长时间内可自然控制害虫消长，导致相继世代害虫持续带毒，感染死亡。与其他化学农药和其他生物农药相比，作为生物杀虫剂，最大的优势还在于病毒杀虫剂目前未发现抗性问题，这就为病毒杀虫剂当今的发展带来了良好的契机。１重组病毒杀虫剂昆虫病毒作为生物杀虫剂具有毒力高、无抗性，用后…