Screening of Chemical Control for Potato Blight

To screen chemicals for controlling potato blight effectively, randomized block experiment was adopted, the control efficiency of five chemicals for Carbendazim, Metalaxyl, Dithane mancozeb, Curzate, Cymoxanil mancozeb was explored. The results showed that the efficiency of Metalaxyl was much better than that of other conventional chemicals in controlling potato blight, up to 70.59% ; the mean control efficiency of Curzate and Cymoxanil mancozeb was 68.76% and 67.05% ; the control efficiency of Carbendazim was lower, 55.76%. Big and middle tuber rate, tuber weight per hole, plot yield, unit area yield of potatoes in Metalaxyl treatment were the highest, 78.05%, 437.24 g/hole, 34.0 kg/21.6 m2 and 15 748.61 kg/hm2, 49.12% higher than the control yield. The indexes of potatoes in Cymoxanil mancozeb treatment were the second highest, 73.33%, 385.31 g/hole, 32.8 kg/21.6 m2 and 15 192.78 kg/hm2, 43.86% higher than the control yield.

Potato late blight caused by Phytophthora infestans:From molecular interactions to integrated management strategies

Over 170 years after the infamous Irish Potato Famine,potato late blight(PLB)caused by Phytophthora infestans remains the single most devastating disease of global potato production,causing up to 10 billion USD in yield loss and management costs.Through decades of research,growers and agronomists in the field as well as laboratory scientists have made significant progress in understanding the molecular pathogenesis process of this critical pathosystem and effective management strategies to control PLB.Yet,the need to feed an ever-increasing global population under changing climate demands continued improvement in efficient and sustainable PLB management schemes that can be implemented across a broad economic spectrum.In this review,we briefly summarize the current understanding of the molecular interaction between P.infestans and its host plants,highlight the current integrated pest management strategy to control PLB on local and continental scales,and discuss the potential of further improvement of sustainable PLB control through genetic enhancement of crop resistance and emerging crop protection technologies.

Control Efficacy of 45% Propamocarb·Denamidone SC against Potato Late Blight

The effects of different doses of 45% pmpamoearb · fenamidone SC on potato late blight were studied in the paper. The results showed that the overall control effect of 45% propamocarb · fenamidone SC against potato late blight on the 14^th day after the third spraying were 67.64% -83.78%. The yield of potato reached 19 972.5 -23 302.5 kg/hm^2, with higher marketable tuber rate and lower rotten tuber rate. With the increase in fungicide dose, the difference in control effect against late blight was significant, but the yield-increasing effect on potatoes was not significant. The appropriate application dosage of 45% propamecarb · fenamidone SC were 450 -675 g/hm^2.

Occurrence and Damage and Pathogene of Potato Early Blight in Winter in Yunnan Province,China

[Objectives]The paper was to understand the species and pathogenicity of the pathogen causing potato early blight in winter.[Methods]The occurrence of potato early blight was investigated in 5 winter potato growing areas in Yunnan Province.The disease samples were collected from two locations(Zhutang Village and Zhanai Village,Pu'er City)where the occurrence of early blight was severe.The pathogen was isolated and purified in laboratory and identified by morphological characteristics and phylogenetic analysis of ITS gene sequence.And it was further verified via re-inoculation by Koch's rules.The growth characteristics and pathogenicity of isolates in different seasons were analyzed with 4 strains of Alternaria isolated in spring(EYZ,EYAX,TA1 and TAC)as controls.[Results]Early blight occurred in varying degrees in the 5 winter potato growing areas,and the incidence of early blight was up to 100%in some plots in Lancang County,Pu'er City.A total of 35 strains of Alternaria were isolated from plots with high incidence,which were divided into two types according to colony morphology.The first type was round colonies with smooth edges and gray white fronts,and the second type was round colonies with rough edges and gray black fronts.Three strains LC1,LC2,LC3 of the first type and two strains ZT3 and ZT8 of the second type were selected and identified as Alternaria alternata through morphological and molecular identification.Re-inoculation test further confirmed that the pathogen was A.alternata.Meantime,it was found that the growth rate of colonies isolated in winter was relatively slow,and there was no significant difference between the pathogenicity of LC1 and TA1,but the pathogenicity of strains isolated in winter was generally higher than that isolated in spring.[Conclusions]It is confirmed that the pathogen causing potato early blight in winter is A.alternata in Yunnan Province.The results will lay a foundation for the research of pathogenesis,occurrence regularity and disease control of A.alternata in winter potato.

<i>In vitro</i>and greenhouse evaluation for resistance to early blight of potato isolated from <i>Alternaria alternata</i>

Early blight of potato is caused by the fungus Alternaria alternata, one of the most destructive foliar diseases, especially in hot climates under irrigation. In this study, the virus free potato seedlings were obtained from the National Plant Gene Bank of Iran and were inoculated in vitro with a culture filtrate of A. alternate. The leaflets received a 1000-μl droplet of the A. alternata culture filtrate and were inoculated by spraying with a suspension of 105 conidia/ml of isolate A. alternata in the greenhouse method. The experimental design was a completely randomized design (CRD) with three replications and seven genotypes, which have been infected with the two leaves of each iteration. In vitro selection of fungal isolates of A. alternata, chlorotic and necrotic symptoms began 1 to 2 days after inoculation, but the assessment of greenhouse symptoms appeared 6-10 days after inoculation. The area under the disease progress curve values were presented by analysis of variance (ANOVA), and they were compared using Duncan’s test (a = 0.01%). In both methods, there was a significant difference between the potato genotypes (P In vitro selection and evaluation greenhouse, Casmos were resistant to at least figure and Marfona genotype had the highest resistance.

Population Improvement of Resistance to Late Blight in Tetraploid Potato:A Case Study in Combination with AFLP Marker Assisted Background Selection

Cultivated potato with high level of horizontal resistance against late blight is one of the most important goals of potato breeding.The recurrent selection has been adopted to increase the level of potato horizontal resistance and a B3C1 population without R1-R11 dominant genes has been released by the International Potato Center at the short-day condition of Peru.The present research was carried out to further improve the resistance and the agronomic traits of B3C1 population under long-day condition of Hubei,China,with maximized retention of its genetic diversity.Twenty-seven individual clones of B3C1 were used to generate population B3C2 by in-population crossing with the bulk pollens aiming to elevate the frequency of late blight resistance genotypes and to improve the adaptation to local long-day conditions.The late blight resistance and the main agronomic traits including the maturity,the plant characters and the tuber traits were evaluated for the foreground selection in three years,by which 130 pedigrees were maintained as the basic population of B3C2 for further selection.A total of 312 polymorphic loci detected by 9 AFLP marker combinations were used to monitor the genetic diversity of the populations for the background selection.The B3C2 population of 51 clones was finally selected,of which the frequency of resistant genotypes increased by 23.8% points and the genetic diversity was maintained by about 96% as referred to B3C1.Our results strongly suggested that combination of the foreground selection for target traits and the background selection for the genetic diversity is an efficient strategy in the recurrent selection of tetraploid potato to improve quantitative traits.

Assessment on early blight of potato in order to compare the two methods<i>in vitro </i>using pathogenic fungi <i>Alternaria solani</i>

Potato (Solanum tuberosum) early blight, caused by Alternaria solani is one of the most destructive fungal foliar diseases. This research was done in order to study methods comparison of evaluation by culture filtrate of A. solani in in vitro condition for selecting resistance cultivars to early blight. Plantlets of potato viruse free were obtained from the National plant gene bank of Iran, and were inoculated in vitro methods with a culture filtrate of A. solani. In in vitro selection by droplet of culture filtrate method, leaflet received a 10 μl droplet of the A. solani culture filtrate and in in vitro selection by direct using of culture filtrate method, plantlets were placed in test tubes that include 5 μl A. solani culture filtrate. The experimental design was factorial on basis of completely randomized design (CRD) with two factors, three replications and six genotypes. During droplet method assay, the A. solani symptoms appeared 1 - 2 days until 6 days and during direct method they appeared 2 - 3 days until 6 days. The AUDPC values were submitted to the analysis of varience (ANOVA) and AUDPC means were compared by using Duncan test (α = 0.01%). In each method, significant difference among potato cultivars was observed for disease to early blight (p < 0.01). Results show that casmos cultivar is susceptible for resistance to early blight and in vitro methods experiment had the same result.

Efficacy of Some Botanical Extracts on the Control of Late Blight Disease in Experimental Potato Field

Late blight caused by Phytophthora infestans (Mont.) De Bary is the most devastating disease of potato. This study was carried out to evaluate the efficacy of ten botanical extracts against the late blight disease incidence and severity in experimental potato field at University of Rajshahi, Bangladesh during 2019-2020. Crude aqueous extract of leaves of Syzygium cumini, Psidium guajava, Eucalyptus globusus, Carica papaya and Lawsonia inermis;fruits of Terminalia bellirica, T. chebula and Piper nigrum;flower buds of Syzygium aromaticum and cloves of Allium sativum were used at 5% (w/v) concentration for evaluation. Out of ten botanicals, Syzygium cumini leaves extract was found most effective in controlling the late blight disease incidence and severity up to 66 DAS (days after sowing) and increased the potato yield by 71.29% compare to untreated control. The efficacy of Lawsonia inermis extract against late blight disease was found promising and increased the potato yield by 48.51%. Other four botanical extracts (Terminalia chebula, Piper nigrum, Syzygium aromaticum and Carica papaya) showed moderate efficacy against the incidence and severity of late blight disease, and increased 30% more potato yield compare to control. These results suggest that botanical extract of Syzygium cumini has a great potential as an alternative of chemical fungicides to control the late blight disease of potato in eco-friendly way.

基于CARAH预警系统对8种马铃薯晚疫病新型杀菌剂的防效评估

[目的]筛选马铃薯晚疫病防控新型高效绿色杀菌剂及生物农药,为科学合理使用高效杀菌剂开展马铃薯晚疫病绿色防控提供指导。[方法]在优化的马铃薯晚疫病CARAH预警系统指导下,采用随机区组设计对6种新型杀菌剂及2种植物源农药在马铃薯主栽品种合作88上进行大春马铃薯晚疫病田间药效评估,评价不同杀菌剂对马铃薯叶部和茎部的晚疫病防效。从预测中心病株开始,晚疫病每完成一代侵染进行一次防控。[结果]预警系统预测合作88将在7月2-4日出现中心病株,田间调查显示,对照处理7月3日出现马铃薯晚疫病中心病株,优化的预警系统预测中心病株出现时间的准确率达100%;根据预警系统指导,从7月1日第一次施药至8月30日最后一次施药共开展9次防控。对马铃薯叶部和茎部晚疫病调查显示:8种杀菌剂对马铃薯叶部和茎部晚疫病的防效分别在85.50%和87.50%以上,其中31%噁酮·氟噻唑的防效最高,分别达到95.00%和96.75%;植物源杀菌剂0.3%丁子香酚的防效较高,分别达到90.50%和92.50%。预警系统指导下应用8种杀菌剂对马铃薯增产显著,增产幅度在116.29%~257.69%,对照处理的商品薯率仅为38.27%,杀菌剂防控的商品薯率为71.60%~79.94%。[结论]CARAH系统测报与田间晚疫病的实际发生高度吻合,可精准指导晚疫病防控。6种化学杀菌剂和2种植物源农药对马铃薯晚疫病均有较高防效,推荐在生产中用于晚疫病防控,尤其是植物源农药丁子香酚替代化学杀菌剂的应用可以显著减少化学杀菌剂的使用量。

中国马铃薯晚疫病监测预警系统“China-blight”的组建及运行

马铃薯晚疫病是严重威胁世界马铃薯生产和粮食安全的重要病害之一,同时也是植物病害中流行速度最快的病害之一。由于品种多不抗病,目前国内外主要依靠化学防治控制该病害。为了提高用药的时效性,将信息技术与植物病害流行学原理相结合,设计并组建了中国马铃薯晚疫病监测预警系统"China-blight"(www.china-blight.net)。该系统由"中国晚疫病实时分布"、"未来48小时不同区域晚疫病菌侵染危险性预测"和"晚疫病化学防治决策支持系统"等子系统构成,此外还包括"晚疫病防治方法"、"品种抗病性"、"化学药剂库"、"其他病虫害"、"问题与经验交流"和"用户田间管理电子档案"等知识信息与服务功能。通过对2009年我国北方马铃薯一作区6-7月份病害侵染时段出现次数与晚疫病实际发生情况进行比较,预测信息与病害实际发生程度相符,该系统可以用于对马铃薯晚疫病田间防治的指导。

地质高背景区晚疫病马铃薯根际土壤细菌群落对重金属胁迫的响应

探究地质高背景区重金属胁迫下晚疫病马铃薯根际土壤细菌群落变化及其影响因素,对马铃薯安全生产具有重要意义。采集马铃薯(‘青薯9号’‘威芋5号’和‘威芋3号’)健康植株和晚疫病发病植株根际土壤,检测土壤p H、有机质和重金属含量,用Illumina MiSeq高通量测序技术分析细菌群落;采集马铃薯块茎,测定重金属含量。试验区土壤Cd、Cr和Zn含量均值分别为2.14、170和220 mg/kg,Cd含量超过国家土壤质量标准风险管制值,Cr和Zn含量超筛选值。马铃薯块茎仅1个样品Cd含量为0.103 mg/kg,超过国家食品安全限值标准。发病马铃薯根际土壤优势细菌门及其相对丰度主要为变形菌门(Proteobacteria)33.16%~39.09%、放线菌门(Actinobacteria)13.45%~17.11%;优势菌属主要为鞘脂单胞菌属(Sphingomonas)8.78%~12.30%、芽单胞菌属(Gemmatimonas)6.22%~7.61%,发病植株优势菌相对丰度与健康植株存在差异。不同品种间细菌多样性与丰度不同,马铃薯感染晚疫病后根际土壤细菌群落多样性升高,细菌菌群丰度下降。主成分分析显示发病植株与健康植株细菌群落差异性贡献率为29.59%。冗余分析结果表明,土壤重金属和pH显著影响土壤细菌群落组成和结构,对优势菌群的影响尤为明显,健康与发病植株间细菌群落的差异受土壤Pb、Cr胁迫的影响更大。因此,地质高背景区重金属胁迫下马铃薯可实现安全生产,染病马铃薯植株根际土壤细菌群落多样性降低,丰富度上升,土壤Pb、Cr通过改变根际土壤细菌群落有益菌类而影响晚疫病的发生和发展。

卷积神经网络结合改进光谱处理方法用于马铃薯病害检测

针对马铃薯早疫病不同染病时期光谱数据受到杂散光和噪声等因素的干扰,以及波段数众多、数据量大且谱带复杂会对光谱的定量和定性分析产生不利影响,研究9种光谱预处理方法,结合实验结果,将预处理方法进行排列组合,扩展改进为16种光谱预处理方法,并与连续投影算法、竞争自适应重加权算法和遗传算法3种特征波段提取方法进行组合得到64种光谱处理方法对原始光谱数据进行优化处理。在卷积神经网络(CNN)分类模型中,大部分经过光谱处理方法优化后的光谱数据分类精度相比原始数据的总体分类精度86.67%明显提高,其中12种光谱处理方法的分类精度达到100%,实现对马铃薯早疫病不同染病时期的理想分类。为进一步对马铃薯早疫病不同染病时期进行定量分析,将经过光谱处理方法处理后的光谱数据使用构建的CNN定量估算模型进行定量分析,结果表明,光谱预处理在优化数据的同时,也会损失数据中对目标变量有用的光谱信息,从而导致经过光谱分析方法处理后的数据结果相对于原始光谱数据的R^(2)和RMSE会出现下降的结果,通过研究使用的融合光谱处理方法对原始光谱数据优化能够进一步提升模型性能,其中基于均值中心化、多元散射校正、移动平均平滑相结合的光谱处理方法的CNN定量估算模型取得了最好的结果,其R^(2)为1说明估算的马铃薯早疫病不同染病时期和实际值拟合程度达到100%拟合,其RMSE仅为0.001 1,表明马铃薯早疫病不同染病时期的估算值与真实值之间的偏差接近0,说明该模型能够对马铃薯早疫病不同染病时期进行完美预测。结果表明提出的CNN能够对马铃薯早疫病不同染病时期进行有效地分类检测和定量分析,将各类预处理和特征波段提取方法按优化目的进行有效组合能够有效提高建模效果,为农作物病害无损、精准、智能化检测提供理论和技术支持。

不同药剂混配使用对榆林地区马铃薯早疫病的田间防效试验

采用田间喷雾施药,在陕西省榆林市进行了马铃薯早疫病防治技术研究。开展不同药剂混配的防效比较试验。试验结果表明:不同处理均对早疫病有抑制作用,且存在显著差异,其中:苯酰锰锌+精甲霜锰锌、吡唑醚菌酯+枯草芽孢杆菌、代森锰锌+氟噻唑吡乙酮药剂组合对早疫病防效较好,防效分别为74.2%、70.3%、67.6%,兼有防控晚疫病作用,建议推广使用;丙森锌+烯酰吗啉、苯酰锰锌+精甲霜锰锌、氟啶胺+氟菌·霜霉威、嘧菌酯+噁酮·霜脲氰处理的防效较差,依次为:58.9%、54.6%、50.8%和50.5%。

菌糠水提液对马铃薯致病疫霉的抑制机理

菌糠是菌菇生产后残留的物质,含有丰富的无机盐和有机质等成分。利用热水浸提法制备香菇菌糠水提液(water extract from spent mushroom substrate,WESMS),通过紫外分光光度计和Zeta电位及粒径仪对其紫外吸收情况、表面电荷和水中分散粒径进行表征,采用平板渗透法及十字交叉测量直径法计算WESMS对致病疫霉的抑制率,利用光学显微镜和扫描电镜观察病原菌细胞形态的损伤程度,并采用琼脂糖凝胶电泳法分析WESMS对致病疫霉DNA的影响。结果表明,WESMS在紫外线A(UVA,315~400 nm)、B(UVB,280~315 nm)和C(UVC,100~280 nm)波段均有吸收,在水中的分散粒径为3649.27 nm。抑菌试验表明,WESMS对病原菌的生长具有抑制作用,随着提取液体积百分浓度的增加,抑制效果更明显,在高体积百分浓度(6.25%WESMS)作用下对病原菌的抑制率近100%。经WESMS处理后病原菌的菌丝更加扭曲、扁平,且褶皱明显增多,表明WESMS可对细胞造成明显破坏;WESMS处理组的DNA条带亮度暗于对照组,损伤程度与WESMS体积百分浓度呈正相关。研究结果为菌糠的资源化利用及其对马铃薯晚疫病的有效防治提供科学依据和技术支撑。

28%唑嘧菌胺·氟吡菌胺悬浮剂防治马铃薯晚疫病田间药效试验

为明确复配药剂对马铃薯晚疫病的田间防治效果及最佳使用剂量,本研究采用茎叶喷雾处理,定期调查的方法进行田间药效试验。结果表明,28%唑嘧菌胺·氟吡菌胺悬浮剂在210.0~315.0 g·hm^(-2)的有效成分用量下,第一次施药10 d后对马铃薯晚疫病防效可达79.66%~87.56%,第二次施药10 d后对马铃薯晚疫病防效可达80.68%~88.60%,均显著优于对照药剂,且对应有效成分用量少于对照药剂;两次施药后5 d对马铃薯药害等级均为1.0,未见对马铃薯产生明显药害。比空白对照增产16.34%~24.28%,综合用药成本及效果,推荐有效成分用量为210.0~315.0 g·hm^(-2)。28%唑嘧菌胺·氟吡菌胺悬浮剂能够有效防治马铃薯晚疫病并对马铃薯具有一定的增产效果和较好的安全性。

四川省马铃薯主栽品种对晚疫病的抗性评价

【目的】探明四川省马铃薯主栽品种对晚疫病的抗性程度,为马铃薯品种布局和抗病品种选育提供理论依据。【方法】选择四川省生产上15个主栽马铃薯品种[川芋10号、川芋117、川芋56、达芋2号、费乌瑞它(CK)、会-2、丽薯6号、凉薯97、陇薯10号、米拉、青薯9号、蓉紫芋5号、希森6号、夏波蒂和兴佳2号]为研究对象,以相对抗病指数为指标,利用CARAH马铃薯晚疫病预警模型评价15个品种对马铃薯晚疫病的抗性程度。【结果】四川省马铃薯晚疫病侵染病程共8代,极重度侵染、重度侵染、中度侵染和轻度侵染分别发生18次、8次、4次和16次,发生比例分别为39.13%、17.39%、8.70%和34.78%;主要在马铃薯晚疫病第4~5代侵染病程出现中心病株;在15个品种中,无免疫品种,病情指数为9.82~82.65,费乌瑞它(CK)最高,达芋2号最低,达芋2号、丽薯6号、青薯9号、陇薯10号和凉薯97较CK表现为高抗,占供试品种的33.33%;米拉、川芋10号、川芋117和会-2较CK表现为中抗,占26.67%;兴佳2号和川芋56较CK表现为中感,占13.33%;夏波蒂、蓉紫芋5号和希森6号较CK表现为高感,占20.00%。【结论】达芋2号、丽薯6号、青薯9号、陇薯10号和凉薯97高抗晚疫病,在马铃薯晚疫病第5代侵染病程才出现中心病株,可在晚疫病常发区种植,但应加强监测预警防控,以获得较高的产量及经济效益。

致病疫霉对烯酰吗啉和双炔酰菌胺的敏感性动态监测及马铃薯晚疫病田间防治药剂筛选

为明确马铃薯北方一季作区致病疫霉对烯酰吗啉和双炔酰菌胺的敏感性时空动态及常用药剂对马铃薯晚疫病的田间防效,采用菌丝生长速率法测定了2011—2019年采自河北、内蒙古和吉林3省(区)马铃薯主产区的922个致病疫霉菌株对烯酰吗啉和双炔酰菌胺的敏感性,采用茎叶喷雾法于2018年和2019年评估了烯酰吗啉和双炔酰菌胺等7种杀菌剂在推荐剂量下对马铃薯晚疫病的田间防效。结果表明:在时间上,不同年份采集的922株致病疫霉对烯酰吗啉的抗性频率和抗性指数分别为25.71%~100%和0.31~0.50;890株致病疫霉对双炔酰菌胺的抗性频率为0~1.43%,仅于2013年检测到抗性菌株,历年抗性指数均为0.25。在地域上,3省(区)致病疫霉菌株对烯酰吗啉的抗性频率和抗性指数分别为57.19%~66.56%和0.39~0.42;对双炔酰菌胺的抗性频率为0~0.36%,抗性指数均为0.25。田间药效试验结果显示:50%烯酰吗啉可湿性粉剂(有效成分,下同) 300.0 g/hm^(2)对马铃薯晚疫病的防治效果(83.3%~85.6%)高于23.4%双炔酰菌胺悬浮剂140.4 g/hm^(2)的防治效果(76.9%~78.6%)和50%氟醚菌酰胺水分散粒剂75.0 g/hm^(2)的防治效果(70.0%~71.4%)。20%霜脲氰悬浮剂162.0 g/hm^(2)、40%氟醚菌酰胺·烯酰吗啉悬浮剂240.0 g/hm^(2)、43%霜脲氰·双炔酰菌胺水分散粒剂290.3 g/hm^(2)和687.5 g/L氟吡菌胺·霜霉威盐酸盐悬浮剂773.4 g/hm^(2)对马铃薯晚疫病的防治效果为79.8%~86.9%。为此,推荐烯酰吗啉单剂或混剂及双炔酰菌胺混剂在河北、内蒙古和吉林3省(区)继续用于马铃薯晚疫病的防治,但是需密切监测致病疫霉对烯酰吗啉和双炔酰菌胺的敏感性变化并注意与不同作用机理的杀菌剂混用或者交替使用。