Framework Development in Plant Disease Risk Assessment and its Application

This article reviews recent developments in plant disease risk assessment. The role of risk assessment as an application area in macrophytopathology and its contribution to the development of macroscale disease study are discussed. This article also discusses the concepts and components of risk assessment for different end points and the assessment framework of different potential ranges of a new pathogen: establishment range, suitability range, damage range, and dispersal range. Different end points generate risk information suitable for decision makers at different levels. New insights gained from selected major diseases, especially from risk assessment due to the recent global movement of soybean rust, are presented. The role of pathologists in presenting risk information has extended beyond the professional research domain and has become critical in influencing decision-making, evident by soybean rust in both South and North America. The bias components of risk communication are defined, and different levels of receivers for risk information are identified based on their interpretation capability of risk information, bias potential, and utilization of risk information. Lack of predictability of dispersal potential contributes to uncertainty of risk assessment for airborne diseases. Potential research areas in disease risk assessment are discussed.     

农药标准中精密度试验与准确度试验的评价

本文根据正态分布曲线、精密度试验和修改的Horwitz公式,导出允许差、标准差、变异系数与平均值的数学关系,定义理论单位标准差和理论单位变异系数,作为评判数据离散性的依据,对精密度试验和准确度试验进行评价。     

内蒙古地区提高天然降水利用率实用技术及其评价

本文针对内蒙古地区水资源短缺 ,旱灾发生频繁的现状及天然降水利用效率不高的特点 ,结合国内外现有的科研与技术成果 ,根据地处干旱、半干旱地区内蒙古的气候特点 ,提出提高天然降水利用率的各种实用技术方法。并利用地理信息技术 ,根据各种实用技术方法的指标要求 ,结合内蒙古的地形、坡度状况、土壤类型和气象条件 ,在雨养农业区进行实用技术方法的优化分区 ,区划出适宜区域。     

木霉在植物病害生物防治中的应用及作用机制

木霉是植物病害生物防治中应用和研究非常广泛的一类生防真菌。本文阐述了木霉在多种植物病害防治上的应用及防治效果,并概括了木霉在生防过程中对植物病原物的生防机制,包括竞争、重寄生、抗生作用等,以及木霉与植物互作中对植物促生和诱导植物抗性的机制。目前,世界上含木霉的商品化制剂已超过250种,在不同国家地区都取得了良好的防治效果,更多的优秀生防木霉菌株也在通过野生菌株筛选或遗传改良等方式开发。木霉生物防治及机制研究对推广生物防治和减少化学农药有重要意义。     

基于AMSR-E数据的青海省雪深遥感监测模型及其精度评价

基于2002-2008年10至翌年3月6个积雪季的AMSR-E被动微波亮温数据,以青海省为研究区,结合该区43个气象台站实测雪深等气象数据,系统分析雪深模型建立的影响因子,提出研究区样本筛选的方法.对18GHz和36 GHz波段的水平、垂直极化方式的亮温差和实测雪深值进行回归分析,建立了青海省基于AMSR-E亮温数据的...     

氨基寡糖素对桃细菌性穿孔病的防治效果及增产作用研究

为明确氨基寡糖素5%水剂对桃细菌性穿孔病的防治效果和增产作用,特进行了相关试验调查研究。结果表明,在桃树上喷施氨基寡糖素5%水剂后,对桃树主要病害桃细菌性穿孔病的防效可达63%以上,与单独使用常规化学药剂防效基本相等,具有防病、抗病、减少化学农药使用,保护环境的效果;同时可提高果实外观品质,增产率在7%左右。可在桃树生产中大面积广泛使用。     

植物激活蛋白诱导脐橙抗病促生作用

应用植物激活蛋白可显著提高脐橙对炭疽病的抗性,在4月萌芽期和5月份幼果期以500~1000倍液处理,其诱抗效果可达45.69%~50.00%。植物激活蛋白能调节脐橙生长,增强对不良环境的适应性,对日灼病、脐黄病、裂果病三大生理性病害有32.18%~50.54%的诱抗效果。激活蛋白处理的脐橙表现个体均匀,表皮光亮,可溶性固形物增加2.35%~4.78%,产量增加11.02%~15.65%。     

The Effect of Nitrogen on Disease Development and Gene Expression in Bacterial and Fungal Plant Pathogens

Successful colonisation of plants by pathogens requires efficient utilisation of nutrient resources available in host tissues. Several bacterial and fungal genes are specifically induced during pathogenesis and under nitrogen-limiting conditions in vitro. This suggests that a nitrogen-limiting environment may be one of the cues for disease symptom development during growth of the pathogens in planta. Here we review recent literature on the effect of nitrogen and nitrogen-regulated genes on disease development, caused by phytopathogenic bacteria and fungi. Furthermore, the potential influence of nitrogen-limitation or general nutrient limitation on several in planta-induced bacterial and fungal pathogenicity, virulence and avirulence genes will be discussed.     

番茄青枯病生防芽胞杆菌的筛选与鉴定

为了有效利用芽胞杆菌资源,本研究采用抑菌圈法从不同地理来源的芽胞杆菌中筛选出24个对青枯雷尔氏菌具有拮抗作用的菌株。其中,6个菌株对青枯雷尔氏菌的抑菌圈直径大于14.00 mm,菌株FJAT-11709的抑菌圈直径最大,为14.78 mm。盆栽试验比较了6个菌株对番茄青枯病的防治效果,结果表明,菌株FJAT-20261和FJAT-19700防效最好,分别达72.73%和67.77%。通过形态特征、生理生化测定及16S rRNA基因序列分析,菌株FJAT-20261和FJAT-19700分别被鉴定为耐寒短杆芽胞杆菌和特基拉芽胞杆菌。本文报道这2种芽胞杆菌对青枯雷尔氏菌具有拮抗作用,为青枯病的生物防治提供了新的菌株资源。     

Disguising the Leaf Surface: The Use of Leaf Coatings for Plant Disease Control

The ability of fungal pathogens to develop resistance to fungicides and to overcome genetic resistance in their hosts, coupled with growing public concern for the environment, means that there is an urgent need for novel methods of disease control. The leaf surface provides the first barrier that fungi must overcome in order to gain access to the leaf, but it also provides chemical and physical cues that are necessary for the development of infection structures for many fungal pathogens. Film-forming polymers can coat the leaf surface, acting not just as an extra barrier to infection, but also disguising the cues necessary for germling development. Kaolin particle films can envelop the leaf in a hydrophobic particle film barrier that prevents spores or water from directly contacting the leaf surface and as a result, can suppress infection. Adhesion of fungal spores to the leaf surface, which is important to keep spores on the leaf surface and for appropriate development of the fungus on the leaf surface, can be inhibited, leading to reduced infection and lesion development. Polymer and particle films have been shown to provide disease control in the field, while research on agents that inhibit spore adhesion on leaf surfaces is still in its infancy. There is an urgent need for research on the practicality of using these novel methods under field conditions and on ways of integrating them into current crop protection programmes.     

Disease Development and Symptom Expression of Xanthomonas axonopodis pv. citri in Various Citrus Plant Tissues

ABSTRACT Experimental inoculations of Xanthomonas axonopodis pv. citri in different tissues of Tahiti lime and Pineapple sweet orange were conducted monthly under natural conditions on Réunion Island. The interactions between a set of environmental and epidemic variables associated with disease expression and 184 different factor combinations were investigated to determine the parameters needed to explain Asiatic citrus canker (ACC) disease expression. Area under the disease progress curve (AUDPC), inoculation date (Id), fruit and leaf age ratings (FAR and LAR), and number of days during the first 2 weeks postinoculation for which the temperature was less than 14 degrees C (T(min)) or more than 28 degrees C (T(max)) were retained by principal component analysis and canonical correlation analysis as the most meaningful epidemic and environmental variables, respectively. AUDPC as the strongest dependent variable and combinations of the environmental variables as independent variables were used in multiple regression analyses. Tissue age rating at the time of infection was a good predictor for disease resulting from spray inoculation on fruits and leaves and also on fruits following a wound inoculation. Temperature, as expressed by T(min) or T(max), was also a significant factor in determining disease development described by AUDPC. Mature green stems were highly susceptible after wounding, similarly to leaves, but buds and leaf scars expressed the lowest susceptibility. These variations in disease expression according to the tissues will have different impacts on ACC epidemiology.     

植物激活蛋白对白术的抗病增产作用

植物激活蛋白能显著提高白术对病害的抗性,700~1300倍液喷施白术叶面,隔30d一次,对白术根腐病和斑枯病的诱抗效果分别达53.9%~81.2%和39.7%~63.3%。植物激活蛋白能显著提高白术商品性和产量,白术的单术重量增加35%以上,白术产量提高46%以上。6月初使用700倍激活蛋白,间隔30d,整个生长期使用5次对白术抗病增产效果最好,对斑枯病诱抗效果达63.3%,增产129.93%。     

Climatic Zoning and Plant Disease Potential – Examples from the Near and Middle East1

Actual plant disease and pest occurrence depends on many genetic and environmental factors, and frequently obscures the basic suitability of a given location to support or prevent epidemic development. In order to allow the demarcation of climatic zones related to the potential of disease or pest occurrence, we have used long-term average climatic data, especially monthly average temperatures and monthly average rainfall. If applied to sugar beet leaf pathogens such as Cercospora beticola and Erysiphe betae in the Near and Middle Eastern region, some interesting zoning became possible, which could be verified by extended field studies. Other examples that have been analysed in the region are apple scab, Venturia inaequalis, and downy mildew of grapes, Plasmopara viticola. A recent and ongoing analysis of the factors controlling chickpea anthracnose caused by Ascochyta rabiei indicates that the same principle may be applied for very different pathogens. Large-scale planning and control strategies as tried by the International Agricultural Research Centers should therefore be based on careful climatic zoning for plant pest and disease potential, to avoid waste of the limited genetic and financial resources available.     

植物免疫蛋白制剂阿泰灵诱导小麦抗病增产效果及作用机制

阿泰灵是我国自主研发的植物免疫蛋白制剂,能诱导多种植物的广谱抗性,并能促进植物生长、提高产量,但在小麦生产中尚未开展相关研究。2016年作者分别在山东省和河南省开展了阿泰灵对小麦抗病和促生长的田间试验,并初步研究了阿泰灵诱导小麦抗病的作用机制。研究结果表明,用400倍阿泰灵稀释液拌种,并分别在返青期、拔节期和扬花期进行1000倍喷雾使用,能显著提高小麦叶片的叶绿素含量、须根数和根系活力;对小麦纹枯病、白粉病和叶锈病3种病害的诱抗效果达到29.3%~64.9%;穗长、穗粒数和千粒重也显著提高,产量增加15%以上。阿泰灵喷雾处理小麦6叶期幼苗后12~24 h,POD、SOD和CAT防御酶活性提高45%,抗病相关基因PR-1、PR-2和PR-5也比未处理小麦转录表达提高10倍。以上研究结果表明,阿泰灵能有效促进小麦生长,并提高小麦抗病性;防御酶活性提高和抗病基因上调表达是阿泰灵诱导小麦抗病增产的重要作用机制之一。     

Relation between Soil Health, Wave-like Fluctuations in Microbial Populations, and Soil-borne Plant Disease Management

A healthy soil is often defined as a stable soil system with high levels of biological diversity and activity, internal nutrient cycling, and resilience to disturbance. This implies that microbial fluctuations after a disturbance would dampen more quickly in a healthy than in a chronically damaged and biologically impoverished soil. Soil could be disturbed by various processes, for example addition of a nutrient source, tillage, or drying-rewetting. As a result of any disturbance, the numbers of heterotrophic bacteria and of individual species start to oscillate, both in time and space. The oscillations appear as moving waves along the path of a moving nutrient source such as a root tip. The phase and period for different trophic groups and species of bacteria may be shifted indicating that succession occurs. DGGE, Biolog and FAME analysis of subsequent populations in oscillation have confirmed that there is a cyclic succession in microbial communities. Microbial diversity oscillates in opposite direction from oscillations in microbial populations. In a healthy soil, the amplitudes of these oscillations will be small, but the background levels of microbial diversity and activity are high, so that soil-borne diseases will face more competitors and antagonists. However, soil-borne pathogens and antagonists alike will fluctuate in time and space as a result of growing plant roots and other disturbances, and the periods and phases of the oscillations may vary. As a consequence, biological control by members of a single trophic group or species may never be complete, as pathogens will encounter varying populations of the biocontrol agent on the root surface. A mixture of different trophic groups may provide more complete biological control because peaks of different trophic groups occur at subsequent locations along a root. Alternatively, regular addition of soil organic matter may increase background levels of microbial activity, increase nutrient cycling, lower the concentrations of easily available nutrient sources, increase microbial diversity, and enhance natural disease suppression.     

Development and validation of a set of standard area diagrams to aid in estimation of spot blotch severity on wheat leaves

This study aimed to develop and validate a standard area diagram (SAD) set to quantify the severity of spot blotch, caused by Bipolaris sorokiniana, on wheat leaves. The proposed SAD set includes images of leaves with 11 distinct disease severities (0·1, 1, 5, 10, 20, 30, 40, 50, 60, 70 and 83%). The SAD set was validated by 12 raters without experience in evaluating plant disease. Lin's concordance correlation analysis of estimated versus actual disease severity (based on image analysis) showed that precision and accuracy improved for all raters using the SAD set in contrast to assessments made without it. The SAD set improved accuracy (coefficient of bias, C_b = 0·88 and 0·99, without and with the SAD set, respectively) and agreement (Lin's concordance correlation coefficient, ρ_c = 0·81 and 0·96 without and with the SAD set, respectively) of the estimates of severity. The severity estimates were also more reliable when using the SAD set (coefficient of determination, R² = 0·76 unaided and R² = 0·92 with the SAD set, and intra‐class correlation ρ = 0·79 without the SAD set and ρ = 0·95 using the SAD set). The SAD set proposed in this study will improve the accuracy and reliability of estimates of spot blotch severity on wheat leaves.     

江西园林植物病虫害防治地方标准编制初探

对江西省园林植物病虫害防治地方标准的特点、基本构成、编制原则等进行了初步研究。