影响五倍子水悬浮液对马铃薯晚疫病田间防治效果的主要气象因素

 将4.0%五倍子水悬浮液喷施田间马铃薯品种Bintje的叶片,于不同处理时间后,剪下叶片带回室内人工接种致病疫霉孢子囊悬浮液,保湿培养后调查各处理的发病情况。结果表明,喷施五倍子水悬浮液后48h内未经历降雨的处理,病情指数仅为7.41,与清水对照相比,防效为92.59%;喷施后96h接种的处理,由于在田间经历了降雨,完全丧失了防效,病情指数达100。室内毒力测定结果显示,0.4%五倍子水悬浮液喷施96h后,对致病疫霉游动孢子释放的抑制率仍在80%以上,在室外避雨不避光条件下五倍子水悬浮液96h内抑菌效果无显著降低,表明日光的影响作用较小。在室内盆栽条件下,通过喷淋水滴模拟田间降雨对药液的冲刷作用。结果表明,冲刷作用可导致五倍子水悬浮液对马铃薯晚疫病的防效显著降低。进一步说明,降雨是导致五倍子水悬浮液对马铃薯晚疫病田间防治效果降低的主要气象因素。     

近几年我国马铃薯晚疫病流行特点分析与监测建议

马铃薯晚疫病是马铃薯上的重要病害,是影响马铃薯产业发展的主要制约因素。本文系统总结了2008-2014年我国马铃薯晚疫病的发生概况及特点,分析了其影响因素。该病害年度间、地区间、品种间发生不平衡,北方产区受气候因素影响大,西南及中原产区常年偏重发生。2012年、2013年马铃薯晚疫病在全国范围内偏重发生,局部大发生,发生范围广、流行扩展速度快、危害重。在气候、菌源量、品种抗性及防治因素中,气候是影响马铃薯晚疫病发生流行的最重要因素。     

马铃薯与致病疫霉互作研究进展与展望

马铃薯是重要的粮食作物, 由致病疫霉侵染引发的晚疫病长期严重制约马铃薯产业的健康发展, 因此, 国内外均将马铃薯晚疫病列为重大病害。目前, 抗病品种选育栽培、晚疫病预测预报和化学防治等相结合的晚疫病综合防治手段已得到普遍推广, 但晚疫病局部大流行在全世界范围内仍时有发生, 给粮食安全和生态安全带来巨大挑战。本文回顾了我国晚疫病的部分研究历史, 集中关注致病疫霉与寄主的互作机制领域, 梳理了近年来关于致病疫霉侵入机理、效应蛋白毒力功能、病原菌变异规律、马铃薯抗病机理等方面的重要研究结果并展望未来主要的研究方向, 以期为晚疫病基础研究和防治技术革新提供参考。     

Differential interaction of Phytophthora infestans on tubers of potato cultivars with different levels of blight resistance

Differential interactions in tuber blight attack between potato cultivars and Phytophthora infestans isolates were studied using whole tuber and tuber slice assays. Tuber blight incidence and severity were studied in a whole tuber assay, whilst necrosis and mycelium coverage were evaluated in a tuber slice assay. The overall defence reaction of the potato cultivars tested varied considerably. Cultivars like Kartel and Producent showed resistant reactions, whilst Bintje and, to a lesser extent, Astarte reacted more susceptibly after inoculation with aggressive strains of P. infestans . A highly significant cultivar by year interaction was observed when tuber blight incidence was evaluated in two successive years. Differential responses were revealed by changing ranked order of cultivars after exposure to aggressive isolates of P. infestans . The results show that cultivar by isolate interactions existed for all components of tuber blight resistance studied. The quantitative nature of the observed resistance responses suggests the presence of quantitative trait loci governing resistance to tuber blight. The consequences of differential interactions in relation to the stability of tuber resistance are discussed.     

Occurrence of the R1 allele conferring resistance to late blight in potato R-gene differentials and commercial cultivars

A total of 23 Scottish and 14 Dutch potato R-gene differentials as well as five Austrian, two Dutch and two German commercial potato cultivars were screened for the R1 allele conferring resistance to Phytophthora infestans carrying Avr1 , via PCR amplification and sequencing. A single 1400 bp fragment with complete sequence identity to the corresponding part of the R1 allele, was obtained from genomic DNA of all potato R-gene differential clones whose denomination indicates R1 or a combination of R1 and other major resistance factors. The R1 allele was detected, as expected, in all these clones. This fragment also occurred in one Austrian and one German cultivar. Unexpectedly, the same R1 allele also was detected within all R5, R6 and R9 differentials.     

寄主对马铃薯晚疫病菌群体结构的影响研究

对云南省13个寄主品种的马铃薯晚疫病菌群体结构进行研究。结果表明,云南省马铃薯晚疫病菌群体结构复杂,病菌复杂基因型群体增多,生理小种和交配型都趋于复杂化;A1交配型仍然是云南省马铃薯晚疫病菌的主要类型。鉴定生理小种的186个菌株中,共鉴定出100个生理小种类型,优势小种为1.2.3.4.5.6.7.8.9.10.11,占22.1%。品种F44-2、F45-1、PB36、昆引18、F18-1、昆引10和F29-2上都存在优势小种1.2.3.4.5.6.7.8.9.10.11,在各品种中分别占42.1%、31.6%、25.0%、21.1%、61.5%、27.3%和20.0%。滇薯6号、大理7号和克97G10-4的小种类型各不相同,甚至同一品种同一植株上分离菌的小种类型也不相同。在交配型测定过程中,还发现品种F29-2上有2个A2交配型菌株,占这个品种的25.0%,占所测定菌株的1.9%,其小种类型分别为1.2.3.5.6.7.8.9.10.11和2.3.4.6.7.9.10。     

Estimating the global severity of potato late blight with GIS-linked disease forecast models

Global severity of potato late blight was estimated by linking two disease forecast models, Blitecast and Simcast, to a climate data base in a geographic information system (GIS). The disease forecast models indirectly estimate late blight severity by determining how many sprays are needed during a growing season as a function of the weather. Global zonation of estimated late blight severity was similar for both forecast models, but Blitecast generally predicted a lower number of sprays. With both forecast models, there were strong differences between potato production zones. Zones of high late blight severity include the tropical highlands, western Europe, the east coast of Canada and northern USA, south-eastern Brazil and central-southern China. Major production zones with a low late blight severity include the western plains in India, where irrigated potato is produced in the cool dry season, north-central China, and the north-western USA. Using a global GIS data base of potato production, the average number of sprays was calculated by country. These averages were compared with estimates of current fungicide use. The results using Blitecast and Simcast were correlated but only Blitecast estimates correlated with observed data for developed countries. The estimated number of sprays, whether from Blitecast or Simcast, did not correlate with the observed number of sprays in developing countries, and in a number of developing countries the predicted optimal number of sprays was much higher than the actual number observed. In these countries, increased access to host resistance and fungicides could have a strong economic impact.     

Exploiting host resistance to reduce the use of fungicides to control potato late blight

Field trials in 1996, 1997 and 1998 with six potato cultivars differing in levels of foliar and tuber race-nonspecific resistance to late blight were treated with 100, 50 and 33% of the recommended dose of the fungicide fluazinam at application intervals of 7, 14 and 21 days. Using a mixed inoculum of six or seven indigenous isolates of Phytophthora infestans small potato plots were inoculated via infector plants. A foliar blight model for the relationship between the effects of resistance, fungicide application and disease pressure was developed using multiple regression analysis. Cultivars with a high level of quantitative resistance offered the greatest potential for fungicide reduction. The model showed that the effect of resistance on integrated control increased exponentially with increasing cultivar resistance. Reducing fungicide input by lowering the dose resulted in less foliar disease than extending application intervals. The higher the disease pressure, the greater the risk associated with reducing fungicide input by extension of application intervals. The field resistance of cultivars to tuber blight mainly determined the frequency of tuber infection. Exploiting high foliar resistance to reduce fungicide input carried a high risk when cultivar resistance to tuber blight was low. When field resistance to tuber blight was high, a medium level of resistance in the foliage could be exploited to reduce fungicide dose to c . 50%, provided application was at the right time. At a high level of field resistance to both foliar and tuber blight, application intervals could be extended.     

马铃薯晚疫病菌分子遗传及与寄主互作研究

近年来马铃薯晚疫病的重新暴发再次引起世界各国极大关注,特别对马铃薯晚疫病菌的分子遗传学的研究,包括病菌基因组遗传、转录和物理图谱的构建,病菌致病的分子机制以及马铃薯-马铃薯晚疫病菌互作分子机制等。本文就近几十年来对马铃薯晚疫病菌在生物学和病理学,分子遗传学等研究方面作简要综述,并对其研究趋势进行了展望。     

马铃薯晚疫病菌对氟吡菌胺抗性监测及9种常规药剂对马铃薯晚疫病田间防效评估

为探明北方一季作区马铃薯晚疫病菌(Phytophthora infestans)对氟吡菌胺抗性发生动态,2012～2016年自河北、内蒙古、辽宁、吉林、黑龙江等地区采集分离到马铃薯晚疫病菌520个菌株,采用菌丝生长速率法检测供试菌株对氟吡菌胺的敏感性,并以茎叶喷雾法评价9种生产上常用药剂对马铃薯晚疫病的田间防治效果.结...     

Late blight (Phytophthora infestans (Mont) De Bary) development from potato seed-pieces treated with fungicides

Fungicides were applied as seed-piece treatments to control potato late blight, caused by Phytophthora infestans, US8, A2 biotype in controlled environment and field experiments. Efficacy of seed treatments for controlling late blight was examined under three disease development regimes simulated by artifical inoculation; (a) seed-borne infection, (b) transmission of infection resulting from spread during the seed-cutting operation, and (c) infection of foliage by aerial inoculation. Emergence of plants from the seed-borne infection was uniformly low (<40%) in controlled environment and field experiments. In controlled environment experiments some of the plants that emerged from fungicide-treated seed-pieces were infected with late blight. Following exposure of tuber surfaces to P infestans, emergence rates from seed-pieces treated with formulated products that included mancozeb in the formulation were comparable to the untreated and non-inoculated control in controlled environment and field experiments. Plants that emerged from non-inoculated seed-pieces treated with fungicides that contained active ingredients known to be effective against foliar late blight had lower percentage foliar infection after inoculation than the untreated control. Leaves close to the base of the stem had fewer infections than leaves attached at the mid region of the main stem, 14 days after inoculation, in some of the controlled environment studies. In contrast, field experiments conducted under conditions conducive to late blight development showed that none of the seed treatments applied to late blight-free seed-pieces delayed the onset and severity of late blight infection. In potato production areas at risk of early season late blight, seed treatments applied to healthy seed may confer limited protection against late blight between planting and the first scheduled applications of prophylactic foliar fungicides. © 1999 Society of Chemical Industry     

Efficacy of the R2 resistance gene as a component for the durable management of potato late blight in France

Many race-specific resistance genes to potato late blight are overcome in France, but the disease appears later on genotypes carrying the R2 gene. This study examined whether R2 could contribute to durable late-blight control in France, and analysed the conditions of its performance. Plants grown from tubers of different physiological ages showed no difference in R2 expression in field and climate-chamber experiments, demonstrating that the delay in epidemic onset provided by R2 was not the result of gene inactivation in old plants. Among isolates collected at one site, those virulent on R2 were classified into three AFLP profiles. AFLP-VII comprised exclusively isolates virulent to R2 , whereas AFLP-IV and AFLP-V included both virulent and avirulent isolates. No significant aggressiveness differences were observed between virulent and avirulent isolates from AFLP-V; however, isolates from AFLP-VII were significantly less aggressive than virulent isolates from AFLP-V. These results indicate that: (i) the delayed onset of epidemics on R2 cultivars is the result of the breakdown of R2 by virulent isolates; (ii) aggressiveness of isolates virulent to R2 depends primarily on the genetic background of the pathogen where the mutation to virulence occurs; and (iii) this mutation does not lead per se to lower pathogenic fitness. It is suggested that R2 is unlikely to make a lasting contribution to late-blight control in France, and that diversification strategies such as cultivar mixtures might not considerably increase its durability.     

马铃薯晚疫病CARAH预警模型在我国的应用及评价

CARAH预警模型引入我国后,在马铃薯晚疫病监测预警中发挥了重要作用。本文对目前各地CARAH模型的应用情况进行了综合分析,总结了模型在马铃薯晚疫病中心病株出现时间预测、发生程度风险评估、防治效果等方面的作用,分析了品种抗性、区域气候特征等因素对模型应用的影响,提出了进一步研究和完善建议。     

Toxicity of propamocarb to the late blight fungus on potato

Propamocarb (Previcur-N; propyl-[3-dimethylamino-propyl] carbamate-monohydrochloride) was testedin vivo against 32 field isolates ofPhytophthora infestans from six countries. Fungicide dosages required to achieve 90% control of the blight ranged between 676 and 1530 ppm a.i. in potted potato (cv. ‘Alpha’) plants and between 1135 and 2648 ppm in potato tuber slices. Isolates from Israel were less sensitive to the fungicide than isolates from Europe or North America. Toxicity of propamocarb was not related to resistance or sensitivity to phenylamide fungicides (e.g. metalaxyl). Nevertheless, most metalaxyl-resistant isolates from Israel were less sensitive to propamocarb than most metalaxyl-sensitive isolates from this country. Monocyclic epidemics conducted with the 20 Israeli isolates in the field showed that 1081–2012 ppm of the fungicide was required to achieve 90% control of the disease. Laboratory experiments revealed that the fungicide was poorly active against sporangial germination and had a limited curative efficacy. It exhibited a translaminar translocation in leaves but a poor acropetal or basipetal systemicity from foliage. Propamocarb + mancozeb mixtures (1:1, v/w) were synergistically effective in controlling the blight. Growers in Israel use tank mixtures of propamocarb (Dynone) and mancozeb to combat late blight in potato fields where phenylamide-resistant isolates ofP. infestans are prevalent.     

Restriction of potato and tomato late blight development by sub‐phytotoxic concentrations of boron

Boron is a microelement required for normal growth and development of plants but its positive effect is restricted to a narrow range of concentrations. The gradual increase in use of recycled water, which contains high concentrations of boron for irrigation, has already raised the level of boron in soils and plants in southern Israel. This research was conducted to examine the direct effects of sub‐phytotoxic boron concentrations on potato late blight epidemics and to explore the mode of action of boron against Phytophthora infestans. When boron was applied alone to field grown potato plants it did not affect the epidemic. However, together with a reduced rate of the fungicide Melody Duo (propineb + iprovalicarb), boron improved late blight suppression compared to plants treated with the fungicide alone. The ED₅₀ of boron against P. infestans (256·4 mg L^?1) was about 6400 times higher than the ED₅₀ value of the fungicide chlorothalonil (0·04 mg L^?1), indicating that boron does not have a direct fungicidal activity that would explain the level of protection seen in the field. In greenhouse experiments conducted with potted tomato plants, boron decreased late blight severity in both treated leaves and distant leaves not treated with boron. The results suggest that boron is active locally but also may induce systemic acquired resistance against P. infestans.     

知母提取物对马铃薯晚疫病菌的抑制作用及防病效果

 本研究测试了知母提取物对马铃薯晚疫病菌菌丝生长、游动孢子释放、休止孢萌发和孢子囊直接萌发的抑制作用。结果表明,知母的水提取物对菌丝生长、游动孢子释放和休止孢萌发的抑制中浓度分别为1.91mg/mL、1.23mg/mL和1.04mg/mL;对孢子囊直接萌发也具一定的抑制作用,在10.00mg/mL浓度下,抑制率达72.89%。离体叶片测试发现,浓度高于0.5%的知母提取物对马铃薯晚疫病具有显著的防治效果。盆栽植株测试结果表明,1%的知母提取物对马铃薯晚疫病的保护效果达70%以上,防效优于离体叶片试验结果,且持效期可达5d。2%和1%的知母提取物对马铃薯晚疫病的治疗效果不明显。     

Evaluation and analysis of reduction of late blight disease in a diploid potato progeny

The rate of late blight disease was analysed for individuals of a diploid Solanum phureja – Solanum tuberosum dihaploid hybrid population (PD), using three different assessment techniques, in the laboratory, screenhouse, and field. These hybrids expressed low disease rates in the field, comparable to resistance based on intact R genes. However, none of the parents of PD expressed any R genes and the pattern of segregation within the PD population was not indicative of R-gene inheritance. The foliage (or leaflet) area diseased had the largest broad-sense heritability of all criteria analysed, in all tests performed. In the field evaluations, the PD population showed intermediate levels of broad-sense heritability for foliage area diseased, relative to the much larger heritability detected for the group of controls possessing R genes. Resistance in the field of the PD hybrids had very little genotype-environment (G × E) interaction, indicating stability of its expression. All genotypes without R genes exhibited heritable, reduced rates of late blight disease in the field, but they were susceptible with low heritability in screenhouse and laboratory tests. This differential expression of disease indicates that the plants' indirect response to unknown environmental stress in the field may have been measured. The value of the PD hybrids for breeding of late blight resistant potato and the use of the disease rate data for detection of the underlying quantitative trait loci are discussed.     

Control of late blight in potato by full and reduced rates of oxadixyl mixtures

The effect of oxadixyl-based fungicidal mixtures on the development of late blight and the buildup of resistance ofPhytophthora infestans to oxadixyl was studied in potato crops (cv. Alpha) grown in plastic houses. Half-rates of SAN 518F (mancozeb + oxadixyl) applied weekly provided better disease control and reduced resistance buildup more effectively than the full rates of the mixture applied biweekly. Mancozeb applied weekly at full rate was less effective than SAN 518F at half-rate. The data suggest that lowering the dosage together with shortening the interval between sprays is an efficient strategy to combat mixed populations — sensitive and resistant to phenylamides — ofP. infestans when phenylamide-based fungicidal sprays are used.     

Comparison of three diagrammatic keys for the quantification of late blight in tomato leaves

Three diagrammatic grading keys were designed for the assessment of the severity of late blight (caused by Phytophthora infestans ) in tomato leaves. Simplified and broad keys considered, respectively, six (3, 12, 22, 40, 60 and 77%) and eight (3, 6, 12, 22, 40, 60, 77 and 90%) levels of disease severity, whilst a modified key based on a previous proposal for potato late blight considered six levels (1, 5, 10, 16, 32 and 50%). The keys were validated by 24 evaluators who assessed digital images of tomato leaves exhibiting different areas with lesions. Evaluator errors were compared using a mixed model in which evaluators were considered as random effects and the keys and evaluations as fixed effects. The accuracy and precision of the evaluators were compared by simple linear regression between the estimated and actual values of disease severity. The repeatability of evaluators was assessed using Pearson's correlation coefficient. There was significant ( P  ≤   0·001) variability amongst the errors made by evaluators, although the precision of each of the three keys was high with a coefficient of determination (R²) of 0·96, 0·93 and 0·83 for the simplified, broad and modified key, respectively. Repeatability of estimations amongst the evaluators was adequate (correlation coefficients of 0·91, 0·91 and 0·90 for the three keys, respectively). The simplified and broad keys resulted in higher precision and accuracy for the estimation of severity than did the modified key. Since the simplified key considers a smaller number of disease severity levels, its use is recommended in the assessment of late blight in tomato leaves.