共查询到20条相似文献，搜索用时 38 毫秒
1.
Eleven strawberry (Fragaria × ananassa) genotypes from the University of California breeding programme known to be resistant to verticillium wilt were inoculated with Verticillium dahliae. Individual plants were given a resistance score based on the severity of visual symptoms, and the extent of colonization was quantified as the percentage of petioles not colonized by the pathogen. Both resistance scores and the percentage of pathogen‐free petioles decreased significantly from May to June (P < 0·05) during each of two growing seasons, indicating a progression of both colonization and symptom expression. Even the most resistant genotypes had plants with some infected petioles, and manifested some symptoms of verticillium wilt. Significant (P < 0·05) genotypic variance was detected for the percentage of pathogen‐free petioles, but not for resistance score. The percentage of pathogen‐free petioles had a strongly positive genotypic correlation (rg = 0·77, P < 0·01) with resistance score, indicating that about 60% of the genotypic variation for visual symptoms in this set of resistant genotypes was explained by the extent of colonization of individual plants by V. dahliae. Conversely, the genotypic correlation between the percentage of pathogen‐free petioles and the resistance score for plants sampled in May (rg = 0·74, P < 0·01) was smaller than that for plants harvested in July (rg = 0·93, P < 0·01). Together, these results suggest that the overall performance of strawberry genotypes in the presence of V. dahliae can be enhanced by both resistance and tolerance, but that tolerance may be less stable over the course of a season. Distinguishing between these two mechanisms may require evaluations that supplement visual assessments of resistance. 相似文献
2.
Pecan scab (Fusicladium effusum) causes losses of pecan nutmeat yield and quality in the southeastern United States. Disease assessment relies on visual rating, which can be inaccurate and imprecise, with poor inter‐rater reliability. A standard area diagram (SAD) set for pecan scab on fruit valves was developed. A set of 40 images of diseased fruit valves with known severity was assessed twice by 23 raters. The first assessment was conducted without SADs, and the second assessment was made using the SADs as an aid. SADs improved rater accuracy (correction factor, Cb = 0·86 and 0·97, without and with SADs, respectively) and agreement (Lin’s concordance correlation coefficient, ρc = 0·79 and 0·89 without and with SADs, respectively) with true values. SADs improved inter‐rater reliability (intra‐class correlation coefficient, ρ = 0·77 and 0·96 without and with SADs, respectively). The least accurate and precise raters without SADs improved more using SADs compared to the most accurate and precise raters. Experienced raters had significantly higher accuracy and precision compared to inexperienced raters, but only when unaided by the SAD set. There was no significant difference in time to assess images without SADs, but experienced raters using SADs were faster compared to inexperienced raters. There was a slight tendency for faster raters to assess more slowly, and slower raters to assess faster when using SADs. SADs improve rater estimates of pecan scab severity on fruit, and this SAD set should be useful for assessment where greater precision, accuracy and inter‐rater reliability are required. 相似文献
3.
4.
对河北省26个主推玉米品种进行抗玉米粗缩病性鉴定,并对其发病率及病情指数与产量损失率的相关性进行了研究。结果表明:河北省目前玉米生产上主推品种中没有免疫和抗病品种,但感病后品种之间的病情严重度有显著差异,病情指数分布在35.37～80.05,产量损失率为15.55%～74.01%。以邢抗2号、费玉2号、费玉4号、沈玉17和农大108的病情严重度较轻,病情指数低于40,表现为感病,其他品种病情指数都在40以上表现为高感。产量损失率与病株率和病情指数呈显著相关,且产量损失率与病情指数的相关性(R=0.982)比产量损失率与病株率的相关性(R=0.756)更强。 相似文献
5.
S. F. Hwang H. U. Ahmed Q. Zhou S. E. Strelkov B. D. Gossen G. Peng G. D. Turnbull 《Plant pathology》2012,61(5):945-952
The impact on clubroot severity of growing susceptible canola or mixtures of resistant and susceptible canola genotypes was examined. Bioassays revealed greater clubroot severity and incidence, and reduced plant height, where 100% of a susceptible cultivar had been grown. A higher proportion of susceptible plants within a resistant canola crop increased root hair and secondary infections. Regression analysis of root hair infection and the amount of Plasmodiophora brassicae DNA (as determined by quantitative PCR) revealed strong linear relationships between the two parameters. The linear relationships between root hair infection and P. brassicae DNA were stronger for the resistant cultivar than for the susceptible cultivar when regression analysis was conducted by cultivar over the sampling dates. In conclusion, the cropping of a resistant cultivar reduced clubroot severity, while the presence of susceptible volunteer canola increased inoculum potential. Quantitative PCR was a reliable tool for the quantification of root hair infection. 相似文献
6.
Predicting diseases caused by Sclerotinia sclerotiorum in field crops remains difficult, and published literature is largely inconsistent in finding significant relationships with environmental and agronomic factors for various life stages of the fungus. A scoping review was performed to synthesize the current quantitative insights into the role of the environment on the life cycle of S. sclerotiorum and the relationships between various life stages of the fungus and final disease expression under field conditions. For most variables, relationships with stages of the life cycle showed a wide range of responses ranging from closely related (high correlations or r2 values) to not related at all. The effects were often moderated by year, location and/or the presence of another variable such as irrigation, soil type, row spacing or cultivar. Studies that based analysis on a more nuanced understanding of pathogen biology rather than looking only at linear relationships tended to find stronger associations between variables. Yield was consistently negatively associated with disease levels, but cultivar, year, location and planting density were all important determinants of yield. Suggestions for improvement to future research in predictive model development of S. sclerotiorum diseases are discussed. 相似文献
7.
研究了温室条件下45份草地早熟禾材料对腐霉枯萎病的抗病性差异.结果表明,不同接种条件下草地早熟禾的发病率存在显著差异:传统的土壤接种法造成草地早熟禾的发病率最高,可达39.2％;改进的土壤接种法测定的发病率明显低于传统的土壤接种法.相同试验条件下品种间抗病性差异显著,不同的试验条件下同一品种表现出的抗病性不一致,具有相对稳定的特征.温室效果评价获得的高抗品种有:‘公园’、‘午夜’、‘肯塔基,、‘开鲁坦,、‘纳苏’和‘特拉内尔’等,高感品种有:‘莫桑斯克’、‘菲尔京’、‘雪狼’等. 相似文献
8.
我国苹果主要病害研究进展与病害防治中的问题 总被引：22，自引：0，他引：22
苹果是重要的经济作物,2012年中国的栽培面积已超过200万hm2。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。 相似文献
9.
对南京地区苜蓿菌核病进行了田间危害调查、病原菌分离培养和苜蓿品种抗病性评价。结果表明,该病的病原菌为三叶草核盘菌(Sclerotinia trifoliorum),主要发生在每年3月底至4月底,4月初为发病高峰期,造成整株枯死。三叶草核盘菌生长温度为5～30℃,最适生长温度15～25℃,菌丝扩展速度2.43～2.83 cm/d。苜蓿不同品种间抗病性有明显差异,抗病性极强的材料有WL414和WL325,抗性较好的材料有WL323、CS40A和CS40R。 相似文献
10.
Infection and colonization of melon roots by Monosporascus cannonballus in two cropping seasons in Arizona and California 总被引：1，自引：0，他引：1
M. E. Stanghellini † D. H. Kim M. M. Waugh D. M. Ferrin T. Alcantara S. L. Rasmussen 《Plant pathology》2004,53(1):54-57
Although canopy collapse of melons (one of the above-ground symptoms of vine decline caused by Monosporascus cannonballus ) occurred late in the growing season, the onset of root infection occurred much earlier. In three early winter-spring and two late winter-spring crops, the onset of root infection occurred 47–65 and 35–36 days after planting, respectively. In contrast, in four summer-autumn crops, the onset of root infection occurred within 9–17 days after planting. Vine decline occurred commonly in winter-spring crops, but did not occur in any of the summer-autumn crops. Following the onset of root infection, the percentage of plants infected increased at rates of 0·031–0·036 and 0·038–0·070 per unit per day for winter-spring and summer-autumn crops, respectively, based on the monomolecular disease progress model. Root lesions were first observed 14–42 days after the onset of infection in winter-spring crops, and 14–28 days after the onset of infection in summer-autumn crops. Pathogen reproduction occurred primarily at the end of each growing season. 相似文献
11.
Michelle T. Hulin Andrea Vadillo Dieguez Francesca Cossu Samantha Lynn Karen Russell Helen C. Neale Robert W. Jackson Dawn L. Arnold John W. Mansfield Richard J. Harrison 《Plant pathology》2022,71(4):949-965
Bacterial canker is a major disease of stone fruits and is a critical limiting factor to sweet cherry (Prunus avium) production worldwide. One important strategy for disease control is the development of resistant varieties. Partial varietal resistance in sweet cherry is discernible using shoot or whole tree inoculations; however, these quantitative differences in resistance are not evident in detached leaf assays. To identify novel sources of resistance to canker, we used a rapid leaf pathogenicity test to screen a range of wild cherry, ornamental Prunus species and sweet cherry × ornamental cherry hybrids with the canker pathogens, Pseudomonas syringae pvs syringae, morsprunorum races 1 and 2, and avii. Several Prunus accessions exhibited limited symptom development following inoculation with each of the pathogens, and this resistance extended to 16 P. syringae strains pathogenic on sweet cherry and plum. Resistance was associated with reduced bacterial multiplication after inoculation, a phenotype similar to that of commercial sweet cherry towards nonhost strains of P. syringae. Progeny resulting from a cross of a resistant ornamental species Prunus incisa with susceptible sweet cherry (P. avium) exhibited resistance indicating it is an inherited trait. Identification of accessions with resistance to the major bacterial canker pathogens is the first step towards characterizing the underlying genetic mechanisms of resistance and introducing these traits into commercial germplasm. 相似文献
12.
上世纪60年代初我国华东和华北地区分别发现了水稻黑条矮缩病和玉米粗缩病,后来都分别发生了2次大流行,同时都以病害防治为目标分别开展了研究,探明了当地病害发生规律,提出了相应的防治方法,获得了不同程度的防病效果.80年代以来,水稻黑条矮缩病的发生报道仅限于华东地区局部地市,玉米粗缩病的发生涉及华北、东北、西北、西南和华中地区13个省市.根据各地对两病病原形态、寄主及症状、介体昆虫及传病特性等方面相似性的报道,提出了我国玉米粗缩病与水稻黑条矮缩病病原异同性问题.经近10年来对两病用生物学和分子生物学方法进行比较鉴定,证明我国玉米粗缩病和水稻黑条矮缩病病原同属水稻黑条矮缩病毒(RBSDV).同时基本探明了水稻黑条矮缩病在浙江杂交稻区和华北玉米区的再次流行成灾的原因,提出了相应的防治措施,并有效地控制了病害的流行危害. 相似文献
13.
A decline of unknown aetiology has become a major problem for commercial orchid production in Hawaii, one of the primary orchid‐producing states in the USA. The major symptoms of decline include root degradation, foliar blight, pseudobulb rot and sheath rot. It was unclear whether all these symptoms are caused by the same or different pathogens, but preliminary research indicated that Fusarium species may be involved. In this study, the incidence of Fusarium species was examined across 186 plants, from 29 orchid genera and intergeneric hybrids across three islands in the state of Hawaii. The main five species associated with diseased orchids were F. proliferatum (38% of samples), F. solani (16%), F. oxysporum (16%) and two previously undescribed species (8% for both species combined). The two undescribed species were similar in appearance to F. subglutinans, and were designated FS‐A and FS‐B. Pathogenicity tests established that both F. proliferatum and FS‐B caused foliar spots, foliar blight and pseudostem rot on Dendrobium orchids, and that F. proliferatum isolates from diseased tissue of several genera could also induce symptoms on Dendrobium orchids. Although orchids have increasing importance in floriculture, relatively little is known about orchid pathogens, and previous studies focused primarily on Cymbidium and Phalaenopsis. This study provides new information concerning Dendrobium orchid pathogens and suggests a much wider host range than previously recognized for the five Fusarium species recovered from tissue with symptoms. These findings can contribute to better management of Fusarium diseases, which represent a significant challenge to orchid production in Hawaii. 相似文献
14.
Simone Albino Paes André Wilson Campos Rosado Ailton Reis Olinto Liparini Pereira 《Plant pathology》2022,71(2):386-399
In Brazil, sour rot is an important postharvest disease on fruits and vegetables. Geotrichum candidum (synonym Galactomyces candidus) has been reported as the main species causing this disease. However, the identity of the causal agent is still uncertain. This research aimed to determine the identity of 165 fungal isolates associated with sour rot obtained from fruits and vegetables in Brazil, and to evaluate the effect of different temperatures on the incidence of sour rot on artificially inoculated tomato fruits. Based on the phylogenetic analyses of DNA sequences from the D1/D2 domain of the large subunit (LSU) rRNA gene and morphological analyses, 129 samples belonged to Galactomyces candidus, 15 to G. candidum var. citri-aurantii, 6 to G. phurueaense, 2 to Gal. pseudocandidus, 1 to Hyphopichia burtonii, 1 to H. khmerensis, 3 to Saccharomycopsis crataegensis, 1 to S. vini, 1 to Magnusiomyces tetrasperma, 1 to Trichosporon coremiiforme, and 1 to Zygoascus meyerae. Two new species were found, namely, Geotrichum solani (on potato) and Geotrichum spondiadis (on red mombin). All isolates were pathogenic when inoculated on healthy tomato fruits, including the new species of Geotrichum, which were also inoculated into their respective hosts, that is, potatoes and red mombins. To the best of our knowledge, this study is the first to report the presence of five other genera besides Geotrichum associated with sour rot on fruits and vegetables in Brazil, which demonstrates the diversity of fungi and yeasts associated with this disease. 相似文献
15.
In recent years black dot ( Colletotrichum coccodes ) has become an economically important disease problem in potato ( Solanum tuberosum ). It is characterized by silvery lesions on the tuber surface which result in a deterioration in skin quality. In addition to causing tuber blemish symptoms, C. coccodes also causes symptoms on stems and foliage, resulting in crop losses in some countries, and is implicated as a factor in the potato early dying disease complex. In the past, the incidence and severity of black dot might have been underestimated, as tuber symptoms were often mistaken for silver scurf ( Helminthosporium solani ). Inoculum of C. coccodes can be both seed tuber- and soilborne, and disease control is difficult as there are few chemical control methods and little resistance in commercial cultivars. Cultural control options offer the only potential means to control this disease at present. Current developments in rapid and specific PCR-based detection methods are being used to address epidemiological questions. 相似文献
16.
甘肃省红豆草病原真菌鉴定及病害发生动态调查 总被引：4，自引：1，他引：3
为明确甘肃省红豆草的病害种类、发生动态和危害状况,采用病原物分离与培养、形态学及分子生物学鉴定和致病性测定确定红豆草病害种类,于2012—2013年在通渭、渭源、榆中和碌曲4县调查各病害的发病率以确定发生动态,观察病害田间发生特点并结合调查数据评价其重要性。结果表明,4县共发生真菌性病害12种,分别为大茎点霉叶斑病(病原为大茎点霉属真菌Macrophoma sp.)、壳针孢叶斑病(病原为歪头菜壳针孢Septoria orobina)、炭疽病(病原为白蜡树刺盘孢Colletotrichum spaethianum)、黑秆病(病原为红豆草壳二孢Ascochyta onobrychis、菠菜刺盘孢C.spinaciae和链格孢Alternaria alternata混合侵染)、壳二孢叶斑病、茎点霉叶斑病、尾孢叶斑病、柱格孢白斑病、匍柄霉叶斑病、链格孢黑斑病、锈病和白粉病,其中大茎点霉属真菌、白蜡树刺盘孢和菠菜刺盘孢在红豆草上首次发现;尾孢叶斑病和壳针孢叶斑病为甘肃新记录病害;大茎点霉叶斑病为世界新病害,仅于碌曲县发现。白粉病、锈病、链格孢黑斑病发生于红豆草生长后期,其它病害则始于6月;6—9月危害加重的为黑秆病和柱格孢白斑病,发病率最高达89.7%和96.0%;危害渐轻的为茎点霉叶斑病、壳二孢叶斑病和壳针孢叶斑病,发病率最高达88.7%、57.4%和45.1%。黑秆病和茎点霉叶斑病在甘肃省目前危害最重。 相似文献
17.
Ramón E. Jaimez Danilo I. Vera Argenis Mora Rey G. Loor Bryan A. Bailey 《Plant pathology》2020,69(4):698-712
Frosty pod rot (FPR) (Moniliophthora roreri), along with black pod rot (Phytophthora species) and witches’ broom disease (Moniliophthora perniciosa) constitute the main phytosanitary problems limiting cacao (Theobroma cacao) production causing severe yield losses. One of the main sought after methods of pod rot management is the selection of tolerant cacao genotypes. Typically, the selection is carried out through the quantification of the percentage of diseased pods (PDP). However, PDP does not consider the relative productivity, or production potential (PT) of the genotype. Production potential can vary among cacao genotypes. Consequently, genotypes with similar PT can have similar or vastly different disease tolerance levels as measured by PDP. The disease and production index (DPI) was developed to integrate a genotype's tolerance to M. roreri and other diseases as measured by PDP, with its PT. Here, we evaluated the number of healthy pods, number of diseased pods, and weight of fresh seed for 29 clones grown in replicated five-tree plots over 4 years. The data obtained was used to calculate PDP and DPI for each clone for three different disease combinations: frosty pod rot alone, pod rots other than frosty pod rot, and the combination of all pod rots. Multivariate analysis verified that DPI discriminated between clones based on productivity and disease tolerance. Surprisingly, there was a close ranking of clones between resistance to FPR and resistance to all other pod rots. The DPI can be used in breeding programmes focused on the selection of high yielding disease-tolerant cacao genotypes. 相似文献
18.
19.
20.
为了建立简易、有效的根肿病生防体系,本研究采用浇灌和喷施枯草芽胞杆菌XF-1的绿色荧光蛋白标记菌株XF-1-gfp,测定其在大白菜植株内的定殖能力,并用野生型菌株XF-1发酵液研究其防治根肿病和挽回产量效果。结果表明,叶面喷施XF-1-gfp发酵液后,标记菌在大白菜根、茎、叶等组织内的密度呈现出"先上升后下降最后趋于平稳"的趋势,最终稳定在约10~3 cfu/g组织;盆栽试验结果表明,与空白对照相比,所有处理发病率和病情指数均显著下降,喷施XF-1发酵液后最佳防治效果为56.4%,浇灌化学杀菌剂10%氰霜唑悬浮剂2 000倍液及1×10~7 cfu/mL的XF-1发酵液防效分别为78.6%与70.7%。大田试验结果表明,喷施XF-1发酵液后防治效果达52.6%,与浇灌化学杀菌剂10%氰霜唑悬浮剂(64.6%)及XF-1发酵液(74.0%)相比无显著差异。此外,与空白对照、浇灌10%氰霜唑悬浮剂及XF-1发酵液相比,喷施XF-1发酵液后大白菜单株产量分别增加了74.0%、35.1%及23.6%。试验结果表明叶面喷施XF-1发酵液是一种有效的防控大白菜根肿病及增产增收的方法。 相似文献