马铃薯粉痂菌诱饵植物筛选及环境对病害发生的影响

通过筛选获得土壤中马铃薯粉痂菌的诱饵植物,明确不同地区土样的含菌量以及马铃薯栽培品种对土壤含菌量的影响;同时,研究温度和土壤含水量对马铃薯粉痂病发病情况的影响。采用带菌土壤诱导和带菌薯块诱导两种活体诱导的方法进行马铃薯粉痂菌的诱导;在温室条件下设计不同的处理来研究温度和土壤含水量对马铃薯粉痂病发病的影响。筛选得到诱饵植物为番茄品种‘3-375’,不同地区和种植不同马铃薯品种的土壤中粉痂菌的含量存在差异。温度和土壤含水量对粉痂病发病情况有一定影响。土壤中存在马铃薯粉痂菌,该病原菌可以通过土壤和种薯传播;温度和土壤含水量等环境因素对该病害的发生有影响。     

几种化学药剂处理对马铃薯粉痂病的防治效果

近年来,粉痂病已成为内蒙古自治区马铃薯生产上的主要病害之一,目前针对该病害没有有效的防治药剂和措施。为筛选出有效的药剂防治马铃薯粉痂病,于2015年在阴山北麓地区开展马铃薯粉痂病大田防治药剂筛选试验,并采集带菌土样进行室内盆栽药剂筛选试验。室内试验结果表明,土壤带菌是主要的初侵染源,带菌薯次之;4.5 L/hm2氟啶胺拌土、120倍或150倍液氟啶胺浸种处理对粉痂病的防治有较好效果,发病率和病情指数显著下降。大田试验结果表明,120倍液氟啶胺浸种结合3 L/hm2沟施和4.5 L/hm2块茎形成期灌根处理对粉痂病的防治有一定效果,病指防效为36.4%。     

定西市部分主栽马铃薯品种块茎晚疫病发病情况调查

2012年在马铃薯收获期间,对定西师范高等专科学校马铃薯试验田5个定西市主栽马铃薯品种‘费乌瑞它’、‘早大白’、‘新大坪’、‘陇薯3号’和‘克新1号’块茎晚疫病发病情况进行了调查。结果表明:5个品种中晚疫病发病率均较高,且不同品种存在明显差异,由高到低依次为‘费乌瑞它’(52.54%)、‘早大白’(47.49%)、‘新大坪’(46.21%)、‘克新1号’(23.42%)、‘陇薯3号’(16.03%)。说明‘陇薯3号’对晚疫病的抗性最好,其次为‘克新1号’,‘费乌瑞它’的抗性最差,‘新大坪’和‘早大白’对晚疫病的抗性较低。除晚疫病之外,在不同品种中还发现了粉痂病、黑痣病和疮痂病,具体为:‘费乌瑞它’中疮痂病的发生频率为10.59%;‘新大坪’中粉痂病的发生频率为4.12%;‘早大白’中黑痣病的发生频率为8.94%;‘克新1号’中粉痂病、黑痣病和疮痂病的发生频率分别为1.27%、3.80%和3.80%;‘陇薯3号’中粉痂病和疮痂病的发生频率分别为1.91%和2.67%。     

种植期和接种量对马铃薯粉痂病发病率和严重度的影响

近年来粉痂病(Spongospora subterranea(Wallr.)Lagerh. f. sp. subterranea)在宾夕法尼亚州马铃薯种薯繁育地区(Potter县)危害较大。同本地的其它马铃薯产区相比,整个生长季节温度都较低。由于土壤水分和温度是粉痂病发展的重要因素(De Boer等,1985     

光照长度、强度及温度对试管薯诱导的影响

通过一步法进行试管薯的诱导,不更换培养基,不添加任何外源激素,研究试管苗培养阶段光照周期、光照强度及温度对Favorita、Atlantic和克新1号3个马铃薯品种试管薯诱导的影响。结果表明:短光周期培养有利于试管薯的诱导,但产生的试管薯较小,适当的延长光照时间有利于诱导较大的试管薯;不同品种需要不同的适宜试管薯诱导的光照强度;变温处理最适于试管薯的诱导。不同品种需要做培养环境的筛选和品种结薯性评价,以筛选出最佳的诱导条件。     

马铃薯疮痂病和粉痂病的防治

马铃薯疮痂病和粉痂病通过种薯传播和土壤传染。这两种病害的病原菌侵入块茎的表皮形成病斑,直接降低商品价值。日本静冈县从1970年开始,这两种病害发生成灾。此后发病逐年扩大,现已蔓延全县。以静冈县西部的浜松市、湖西市为中心的马铃薯主产地,发生疮痴病和粉痂病,该县东部以三岛市为中心疮痂病发生较重。因此,急需找出防治措施。本文     

马铃薯枯萎病初侵染来源及栽培与发病的关系

马铃薯枯萎病(Fusarium oxysporum)是一种重要病害,重茬地发病重,对马铃薯生产造成威胁。为了解该病发生规律,试验进行了枯萎病初侵染来源及栽培与发病关系的研究。盆栽试验结果表明,土壤接菌的植株萎蔫率、病株率及病薯率分别为36.7%、58.3%和71.3%,播种带病种薯的植株萎蔫率、病株率及病薯率分别为11.7%、18.0%和21.4%,由此明确土壤带菌是主要的初侵染来源。田间不同施肥种类及栽培方式对病害发生的影响。试验结果表明:合理施肥均能延缓植株发病,其中施用尿素的植株萎蔫率、病薯率分别是13.3%、47.1%,显著低于CK及其它施肥处理,产量达到最高,为2 202 kg/667 m2;其次是马铃薯专用肥及碳酸氢盐类处理,均比CK植株萎蔫率低,产量有所增加。采用覆膜起垄栽培可以有效降低病薯率。     

六种杀菌剂对马铃薯粉痂病的盆栽防治效果

随着马铃薯产业的持续发展,马铃薯粉痂病已成为限制马铃薯种植的重要土传病害,为筛选能有效防控其发生危害的杀菌剂供生产应用,研究采用盆栽拌土和灌根的方法比较了6种杀菌剂对马铃薯粉痂病的防治效果。结果表明,3种杀菌剂对马铃薯粉痂病的防治效果显著,分别是50%嘧菌环胺水分散粒剂、325 g/L苯醚甲环唑·嘧菌酯悬浮剂、560 g/L百菌清·嘧菌酯悬浮剂,防效均达到60%以上,但325 g/L苯醚甲环唑·嘧菌酯悬浮剂对产量影响较大,减产高达84.4%。在生产上可采用50%嘧菌环胺水分散粒剂、560 g/L百菌清·嘧菌酯悬浮剂防治粉痂病,而不推荐使用325 g/L苯醚甲环唑·嘧菌酯悬浮剂。     

浇水次数对马铃薯微型薯疮痂病发病影响

1　前　言马铃薯疮痂病(Streptomycesscabies)为世界性病害,除了pH极酸地区之外,各产地几乎都有发生。此病害在我国许多马铃薯主产区也普遍存在,而在连作地、偏碱地及栽培管理不当的情况下则发生程度更为严重。尤其近几年随着地球温室效应的影响,气候发生了很大变化,年平均温度升高,要么连续干旱,要么连续降雨,疮痂病发生日趋严重。据调查,2002年有的大田地块发病率高达33%左右,微型薯发病则达到80%以上。疮痂病病原菌集生于病薯表皮,由于品种的不同产生病斑和发病率也不同,或造成皮孔褐色开裂形或薯表连片的硬质栓皮性薄痂状而直接影响商…     

四川省冬马铃薯不同生态区品种引进与筛选

为筛选出适宜四川省不同生态区域的冬马铃薯品种,四川马铃薯创新团队在6个不同生态区域开展冬马铃薯品种引进与筛选多年多点试验。结果表明,在成都平原,‘川凉薯9号’和‘凉薯97’表现突出;在川中丘陵区,‘川芋10号’产量最高;在川东地区,产量较高的品种除对照‘费乌瑞它’外,‘中薯2号’和‘中薯3号’产量表现也较高;在川东北山区,引进的新品种‘鄂薯4号’增产显著;龙门山脉地区‘中薯2号’和‘坝薯10号’产量较高;而凉山州安宁河谷地区则以‘青薯9号’高抗晚疫病,产量表现最突出。由此可见,不同生态区域适宜的冬马铃薯品种差异较大,新品种引进与筛选工作应长期坚持。     

Review: Powdery Scab of Potato—Increased Knowledge of Pathogen Biology and Disease Epidemiology for Effective Disease Management

The importance of the potato tuber disease powdery scab, caused by the zoosporic pathogen Spongospora subterranea f. sp. subterranea, has increased worldwide, and the disease is one of the most important problems facing potato production in some regions. This soilborne pathogen produces many resting spores which can remain dormant for long periods, are highly resistant to environmental stresses and can spread the disease on seed potatoes and in contaminated soil. The enigmatic nature of this organism exacerbates the development of effective powdery scab control methods. Substantial knowledge has been gained in the last decade on the biology of the pathogen and the epidemiology of the disease, but no single effective control measure is, or is likely to be, available. An integrated approach to powdery scab management is the aim, with host resistance as a substantial and sustainable component. Further research on the epidemiology of powdery scab and population genetics of the pathogen is urgently required. All stakeholders involved in the potato industry must become aware that solution of the powdery scab problem is likely to be a long-term goal. When resistant cultivars with all the other characteristics demanded for marketing high-quality potatoes are available, and when disease risk from the pathogen on seed and/or in soil can be accurately determined, then the mission to develop effective powdery scab control will become achievable.     

Incidence and severity of powdery scab on potatoes in Pennsylvania

Studies were conducted in Potter Co., Pennsylvania to investigate the effect of powdery scab (Spongospora subterranea) on five potato cultivars (Norchip, Rosa, Kennebec, Katahdin, and Monona) at two planting dates. Soil temperature was within the range of 15–18 C and soil moisture was within 15–19% based on dry weight throughout the season. The effect of planting date was significant at each disease assessment, except for the severity on the fourth assessment. By the end of the season, incidence of scab was 66% or more for all cultivars. Rosa, Kennebec and Katahdin had a greater scab incidence over both planting dates and a greater severity at the first planting date than Monona and Norchip.     

Assessing the resistance of potatoes to powdery scab (Spongospora subterranea (Wallr.) Lagerh.)

Summary The reaction of nine cultivars to infection bySpongospora subterranea (powdery scab) was studied in two successive years of trials in naturally infested field soil and in artificially-inoculated field soil contained in brick-sided beds. The incidence of infection was recorded on a 1–9 scale, with complete absence of the disease scoring 9. The correlation coefficient (r) between scores from bed and field was 0.84 (1985) and 0.81 (1986). The field test gave satisfactory discrimination between resistant and susceptible cultivars in only one year, but the bed test gave good results in both years and is suggested as a small-scale alternative to field trials for this disease.     

Chloropicrin Soil Fumigation Reduces <Emphasis Type="Italic">Spongospora subterranea</Emphasis> Soil Inoculum Levels but Does Not Control Powdery Scab Disease on Roots and Tubers of Potato

The effect of chloropicrin fumigation on the soil populations of Spongospora subterranea and the development of powdery scab, formation of root galls and tuber yield was investigated in seven field trials conducted in Minnesota and North Dakota. Sixteen potato cultivars, with different levels of susceptibility to disease on roots and tubers, were planted in plots treated with chloropicrin at rates ranging from zero to 201.8 kg a.i. ha^?1. The amount of S. subterranea DNA in soil was determined using qPCR. Bioassays were conducted to further assess the effect of chloropicrin fumigation on root colonization by S. subterranea in two potato cultivars with contrasting disease susceptibility. In the field, chloropicrin applied at rates between 70.1 to 201.8 kg a.i. ha^?1 significantly decreased S. subterranea initial inoculum in soil but increased the amount of disease observed on roots and tubers of susceptible cultivars. The effect of increasing disease was confirmed in controlled conditions experiments. Although the amount of S. subterranea DNA in roots of bioassay plants increased with increasing chloropicrin rates, it remained similar among potato cultivars. Chloropicrin fumigation significantly increased tuber yield which in cultivars such as Shepody and Umatilla Russet were associated with the amount root galls (r = 0.30; P < 0.03). Results of these studies contradict earlier reports on the use of chloropicrin fumigation for the control of powdery scab. Factors other than inoculum level, such as environmental conditions that affect inoculum efficiency and host susceptibility, may be significant contributors to the development of powdery scab and root gall formation.     

The effect of irrigation and nitrogen on powdery scab and yield of potatoes

Summary Powdery scab, caused by the fungusSpongospora subterranea, has developed in the Cappodocia region of Turkey because of changes in agronomic practices, such as excessive irrigation and nitrogen fertilizer use and growth of highly susceptible cultivars. The most suitable irrigation and nitrogen application levels were established to maintain powdery scab at minimum levels without affecting potato yield. Three irrigation levels were used in 1998 (673, 897, 1121 mm) and five in 1999 (329, 494, 658, 823, 987 mm). Nitrogen levels were applied 150, 300, 450, 600 kg N ha⁻¹. In 1998, least powdery scab occurred with 673 mm irrigation, which yielded 41 t ha⁻¹ potatoes. The lowest disease severity occurred in 1999 with 494 mm irrigation and 150 kg N ha⁻¹. At these levels, tuber yield was 34 t ha⁻¹ which was not significantly different from the highest yield measured. In 1999 and at two of the three irrigation levels inl998, nitrogen increased disease severity.     

Relationship Between Tuber Storage Proteins and Tuber Powdery Scab Resistance in Potato

The potato genotypes (Solanum tuberosum L.) with russet tuber skin are generally resistant to powdery scab (Spongospora subterranea f.sp. subterranea or Sss). Lipoxygenase (LOX; EC 1.13.11.12) and patatin are two key storage proteins that are known to offer resistance to several diseases and insects. The objective of this study was to find out the relationship of these proteins in stored tubers with potato tuber powdery scab resistance, especially in russet skinned potatoes. An evaluation of potato germplasm with different tuber characteristics in a greenhouse environment over several years (2006–’11) suggests that russet skinned tuber genotypes (Mesa Russet, Centennial Russet and Russet Nugget) with negligible tuber disease severity index (DSI) and 100 % marketability were resistant to powdery scab. Higher physiological levels of LOX protein (on a dry weight basis) were negatively correlated with tuber DSI and positively correlated with tuber russet skin. Tuber total protein and patatin-lipase levels did not have a significant relationship with tuber powdery scab resistance. The proposed role of LOX protein in suberin- and/or non-suberin-mediated mechanisms of powdery scab resistance in russet skinned tubers are discussed here. The physiological levels of LOX protein can be considered as a useful marker for powdery scab resistance in potato breeding programs.     

Potato powdery scab, caused bySpongospora subterranea f. sp.subterranea, in Costa Rica

Summary Seven samples of potato powdery scab like-lesions were used to determine and confirm the occurrence ofSpongospora subterranea f.sp.subterranea in Costa Rica. Light microscope observations of spore balls and zoosporangia in tomato bait plants identified the organism asS. subterranea. Positive DAS-ELISA test results from all seven samples and PCR specific amplification products from five samples confirmed its identity. The geographical location of the samples source plantations suggests wide distribution of the plant pathogen across Costa Rica main potato growing areas. Different lesion types may indicate host-pathogen or environment-pathogen interactions. The symptoms differences and PCR amplification results among specific primer pairs suggest that some degree of genetic variation among theS. subterranea samples may exist; however, further testing is required.     

A Greenhouse Assay for Powdery Scab (<Emphasis Type="Italic">Spongospora subterranea</Emphasis> f. sp. <Emphasis Type="Italic">subterranea</Emphasis>) Resistance in Potato

The plasmodiophorid pathogen Spongospora subterranea f. sp. subterranea causes powdery scab disease of potatoes (Solanum tuberosum L.), which severely affects tuber quality. Adequate chemical control of the disease is lacking, so breeding resistant potato cultivars is important. Little is known about the mechanisms or genetics of host resistance, as the epidemiology of the pathogen makes research on the disease difficult. An environmentally controlled disease screen that allows the accurate and repeatable assessment of diseased tubers (rather than a ranking system) is required to study host resistance in more detail. A high-throughput greenhouse disease assay is described that has been used to assess varying levels of tuber disease resistance of potato genotypes for three consecutive Southern Hemisphere growing seasons (2001–2002, 2002–2003, 2003–2004). This assay allows the evaluation of symptoms on tubers to verify resistance, rather than inferring the tuber infection on the basis of root galling or zoosporangial root infection. The assay was used to determine the level of resistance of genotypes of both known and unknown resistance status. The assay clearly distinguished the susceptible and resistant standards, and the results were highly correlated over the three seasons. The most efficient ways of assessing tuber disease susceptibility of genotypes are discussed. The consistency of the results and the ability to screen many genotypes confirms the value of the assay as a tool for early-generation selection in a plant breeding programme.     

Improved diagnosis of powdery scab (Spongospora subterranea f.sp.subterranea) symptoms on potato tubers (Solanum tuberosum L.)

Summary Based on visual inspection, discrimination between common scab (Streptomyces spp.) and powdery scab (Spongospora subterranea) can be difficult. Inspections are performed on unwashed samples, incidentally supported by microscopic examination. During 1994–1996 surveys were performed in The Netherlands on tubers with symptoms resembling common scab. Under microscopic assessment nearly all samples showed the presence of structures resembling cystosori (sporeballs) ofS. subterranea. At that time confirmation using alternative techniques was not possible. In 2003 research was undertaken to clarify the situation with respect to scab on potato tubers in The Netherlands. One hundred and eighteen scab samples were extensively tested forS. subterranea. All samples were digitally photographed, microscopically examinated and tested with real-time PCR and DAS-ELISA. Use of these modern methods resulted in a clear picture of symptoms that can be attributed toS. subterranea. A lot of scab samples with structures resembling cystosori could not be confirmed as contaminated withS. subterranea.     

Reaction of potato varieties toPotato mop-top virus infection in the andes

The unexpected detection ofPotato mop-top virus (PMTV) in potatoes growing at several locations in the U.S.A. and Canada in 2002 has led to the realization that this soil-borne virus may be widespread throughout the potato-producing regions of both countries. A lack of information concerning the response of U.S. cultivars to PMTV infection caused us to examine the effects of PMTV on field-grown plants at three locations in the Peruvian Andes where the virus and its fungal vector,Spongospora subterranea, are endemic. All 21 U.S. cultivars tested proved susceptible to PMTV infection, especially at La Victoria where the overall incidence of both PMTV and powdery scab was high. Symptom expression in the foliage proved to be an unreliable indicator of virus infection, and thus, more reliable serological (NCM-ELISA) and nucleic acid-based techniques (NASH and RT-PCR) were used to monitor tuber tissue for the presence of PMTV. As much as 25% of field-grown tubers of cvs Kennebec, Monona, and Norland were infected with PMTV, but no correlation between virus infection and either the incidence or severity of powdery scab for any variety was apparent. Although PMTV infection did not result in the appearance of spraing or other internal necrotic reactions resembling those reported from many North American and European locations, a disproportionate proportion of infected tubers did exhibit a reticulate surface cracking. In hydroponic culture, the proportion of cracked tubers increased dramatically when the nutrient solution was seeded with virus-infestedS. subterranea. Comparatively few tubers of cvs Monona and Russet Burbank exhibited this surface cracking, suggesting that these two varieties may be somewhat tolerant to PMTV infection.