板栗贮藏期病害发生规律研究

1997～ 1 999年调查 ,浙江省板栗贮藏期病害发生严重 ,病害率高达 44%～ 82 %。果实腐烂多集中在采后 3 0 d内。病害症状有黑腐、褐变、红腐、干腐、湿腐、青腐、点腐 7种 (列表描述症状 ) ,前期以褐变、黑腐为主 ,后期以干腐为主 ;在贮藏过程中引起板栗果实腐烂主要是多种真菌复合侵染所致 ,病原有鞭毛菌亚门腐霉属 ,接合菌亚门毛霉属、犁头霉属 ,半知菌亚门壳二孢属、曲霉属、葡萄霉属、复端孢属、刺盘孢属、镰霉属、青霉属、轮枝孢属的真菌。同一病原能引起不同的症状 ,同一个板栗病果上可分离出几种病原菌。不同板栗品种的被害率不同 ,…     

桑椹菌核病研究进展

桑椹菌核病是由3种子囊菌真菌引起的相似症状病害的统称,为果桑生产中的毁灭性真菌病害,严重制约果桑产业的发展。这3种病原菌同为死体营养型病原菌,其侵染手段多样,侵染机制复杂。由于3种病原菌在人工培养上存在不同程度的困难(桑实杯盘菌和肉阜状杯盘菌难培养,核地杖菌在人工培养基上不能完成生活史),在一定程度上限制了病原菌的研究。本文综述了桑椹菌核病的侵染循环、病原菌、病害流行、病原菌与寄主互作等方面的研究进展,并对未来的研究进行了展望,以期对桑椹菌核病的深入研究提供参考。     

西双版纳辣木主要病害及病原菌

西双版纳引种的辣木主要病害具体表现症状为:嫩梢萎蔫、枝条溃疡、枝条回枯、果荚褐腐,经病原菌分离、接种和切片镜检,确认是2种病原真菌引起。病原菌经过培养,显微镜观察,鉴定为半裸镰刀菌(Fusarium semitectumBerk.&;Rav.)和黑星菌(Fusicladiumsp.)。     

丹参茎基腐病病原鉴定及防治药剂筛选

近年来,河南丹参产区发生一种新的病害,将其命名为茎基腐病害。为明确该病害的病原,课题组从河南丹参产区采集典型病害标本并进行病原菌分离,共获得25株真菌分离物,其中23个分离物(SM1-SM23)形态与链格孢属真菌一致,2个分离物(SM24-SM25)形态与镰刀菌属真菌一致。选取代表性菌株SM10和SM24对丹参茎基进行致病性测定,分离物SM10能够引起与病样一致的症状,并且在发病部位重新分离出该病原菌,完成科赫氏法则验证。通过形态及分子特征鉴定确定引起丹参芝基腐的病原菌为细极链格孢(Alternaria tenuissima)。在温度为28℃,光暗交替(12 h)最有利于病原菌的生长,pH值在5～11之间该菌生长良好,菌丝生长的最适碳氮源为可溶性淀粉和蛋白胨,产孢的最适碳氮源为乳糖和酵母浸出物。毒力测定结果表明,参试的5种药剂均对A.tenuissima有抑制效果,其中25%吡唑醚菌酯悬浮剂、43%戊唑醇悬浮剂和10%苯醚甲环唑水分散粒剂对病原菌菌丝生长具有较好的防治效果,质量浓度为50 mg·L^-1时抑菌率分别为78.4%、100%和93.3%,可作为防治丹参茎...     

拟茎点霉属真菌检测技术研究进展

拟茎点霉属真菌是植物上重要的病原菌和内生菌,该属真菌已描述900多种,可引起多种病害,呈世界性分布。本文综述了拟茎点霉属检测技术的研究现状,并指出各种检测技术的优缺点及发展趋势。在此基础上,对DNA条形码技术的应用前景进行展望,为拟茎点霉进一步研究提供参考。     

甜瓜真菌性叶斑病研究进展

甜瓜真菌性叶斑病作为多种病原真菌引起的甜瓜叶部斑点病害的统称,主要包括链格孢菌引起的甜瓜叶枯病、甜瓜黑斑病和甜瓜大斑病,瓜类尾孢引起的甜瓜斑点病,瓜灰星霉菌引起的甜瓜叶点病以及棒孢霉引起的甜瓜棒孢叶斑病.针对这几种真菌性叶斑病的病害症状、发生为害、病原菌种类、病害循环及其综合防治进行了综述.     

人工栽培三叶木通褐斑病病原菌鉴定及防治药剂室内筛选

引起三叶木通果实及叶片褐斑的病原菌,经致病性测定、病害症状、病原菌培养性状和形态特征等比较,鉴定为半知菌亚门,丝孢纲,丝孢目,暗色菌科,链格孢属(Alternaria sp.)。经7种化学药剂对该病原菌室内毒力测定,结果表明,80%代森锰锌可湿性粉剂对该病原菌菌丝生长抑制作用最强,其EC50为8.28 mg/L。     

玉米丝黑穗病菌绿荧光蛋白标记菌株的构建与应用

正玉米丝黑穗病病原菌为丝轴团散黑粉菌(Sporisorium reilianum),属于担子菌亚门冬孢菌纲黑粉菌目真菌,其引起的玉米丝黑穗病是一种土传病害,在种子时期或经根系侵染寄主[1]。其侵染方式为系统性侵染,病害症状早期不明显,直到该菌株代替寄主植株的雄性或雌性花序时,才出现典型症状[2,3]。为揭示玉米丝黑穗病菌菌丝体在     

引致大豆根腐病的层出镰孢菌分离鉴定及其特性

层出镰孢菌Fusarium proliferatum是瘤座孢科镰刀菌属的重要植物病原真菌,可侵染水稻、小麦、玉米、芦笋、大蒜、洋葱等作物,引起枯萎病、腐烂病等。2009—2010年,作者在江苏省、安徽省调查大豆病害时,发现层出镰孢菌可侵染大豆而引起大豆根腐病。层出镰孢菌作为大豆根腐病的新病原菌在国内外鲜有报道,所致病害发生特点尚不明确。对层出镰孢菌进行病原鉴定和相关特性研究是病害防控的基础。为此,本试验从大豆根部分离得到层出镰孢菌,对其形态特征和致病性进行研究,并通过ITS序列测定和PRO1/2特异性引物验证,进一步明确其分类地位。     

五味子茎基腐病发生初报

通过对辽宁省多个地区的调查,发现此病害发生普遍,尤其是二年生的五味子茎基腐病发生严重。五味子茎基腐病在5月上旬开始出现,6月初为发生盛期。本文对五味子茎基腐病进行了症状描述,并对不同地点采集的病样分别进行木质部和韧皮部病原物的分离、纯化。对分离得到的菌株按照柯赫氏法则进行致病性测定并对病原菌进行鉴定,结果表明,此病害可由木贼镰刀菌(Fusarium equiseti)、茄腐镰刀菌(F.solani)、尖孢镰刀菌(F.oxysporum)和半裸镰刀菌(F.semitectum)4种镰刀菌属真菌引起。针对此病害的发生特点,提出了相应的防治措施。     

Taxonomy, phylogeny and identification of Botryosphaeriaceae associated with pome and stone fruit trees in South Africa and other regions of the world

Species of Botryosphaeria are well-recognized pathogens of pome and stone fruit trees. The taxonomy of these fungi, however, has been confused in the past. Recent taxonomic changes to the Botryosphaeriaceae further influence the literature pertaining to these fungi. This study reviews the taxonomic status of Botryosphaeriaceae associated with fruit tree diseases, identifies them in South Africa and elsewhere, and develops a reliable identification technique for them. Comparisons were made using DNA sequence data from the nuclear ITS rRNA operon and anamorph morphology. These analyses distinguished six clades amongst isolates associated with fruit tree diseases, corresponding to Neofusicoccum ribis (=  B. ribis ), N. parvum (=  B. parva ), N. australe (=  B. australis ), B. dothidea , Diplodia mutila (=  B. stevensii ) and ' Botryosphaeria ' obtusa (the genus Botryosphaeria is no longer available for the fungus known as B. obtusa , but a new name has not been proposed yet). Isolates from fruit trees in South Africa were grouped in the N. australe and ' Botryosphaeria' obtusa clades. This is the first report of N. australe from fruit trees. PCR-RFLP analysis using the restriction endonucleases Cfo I and Hae III distinguished the major clades. However, two groups of closely related species, N. ribis and N. parvum , and N. australe and N. luteum (=  B. lutea ), had identical RFLP profiles. Using RFLP, it was shown that ' Botryosphaeria ' obtusa is the dominant species on fruit trees in the Western Cape Province of South Africa. These results and methods will be useful in future epidemiological studies and disease management of Botryosphaeriaceae from fruit trees.     

Seasonal dynamics of <Emphasis Type="Italic">Botryosphaeria dothidea</Emphasis> infections and symptom development on apple fruits and shoots in China

Botryosphaeria dothidea is one of the most important pathogens of apple trees in China. It causes warts and cankers on shoots and fruit rot. In this study, multi-season experiments were conducted to investigate the seasonal dynamics of B. dothidea infection and symptom development on twigs and fruits of cv. Fuji through spraying and rain-splash inoculations. Fruit were most susceptible to infection from late May to mid-August. The length of the incubation period, i.e. from inoculation to the first lesion was observed, generally decreased with the age of fruit at the time of inoculation. Fruit inoculated in May–June developed visible symptoms from early August onwards, with a peak in early September. However, fruit inoculated in September developed visible symptoms within one week after inoculation. Twigs remained susceptible to infection by conidia from the initial extension stage in early May to late September. New extension shoots were most susceptible from June to mid-August and then became gradually less susceptible over time. When inoculated before the end of August, twigs developed visible lesions within the same season. In contrast, when inoculated late in the season, most lesions became visible during the subsequent season. The incubation period on twigs was shorter for inoculations conducted in June–August, with the shortest being 25 days. These results may contribute to the improvement of the management of this disease.     

Interactions between citrus viroids affect symptom expression and field performance of clementine trees grafted on trifoliate orange

ABSTRACT Citrus exocortis viroid (CEVd), Citrus bent leaf viroid (CBLVd), a noncachexia variant of Hop stunt viroid (HSVd), Citrus viroid III (CVd-III), and Citrus viroid IV (CVd-IV) were co-inoculated as two-, three-, four-, and five-viroid mixtures to Clementine trees grafted on trifoliate orange to evaluate their effect on symptom expression, tree growth, and fruit yield. Most trees infected with CEVd-containing viroid mixtures developed exocortis scaling symptoms, as did CEVd alone, whereas most trees infected with HSVd- or CVd-IV-containing mixtures developed bark-cracking symptoms. Trees infected with mixtures containing both CEVd and CVd-IV revealed the existence of antagonism between these two viroids in terms of the expected bark-scaling and cracking symptoms. Synergistic interactions also were identified in trees infected with certain viroid combinations that, in spite of lacking CEVd, expressed exocortis-like scaling symptoms. Viroid interactions also affected the expected response of trees in terms of vegetative growth and fruit yield. Trees infected with viroid combinations containing CEVd or CVd-III were smaller and produced less fruit than trees infected with mixtures not containing these viroids. Viroid interactions on scion circumference and cumulative fruit yield, in terms of additivity of their effects, were statistically confirmed using a factorial analysis of variance model with two mean estimation approaches. In single-viroid infections, CEVd, CVd-III, and, to a lesser extent, CBLVd consistently and significantly reduced tree size and fruit yield. Conversely, HSVd and CVd-IV slightly increased fruit yield and reduced scion circumference. Rare and not consistent significant interactions were detected with the five-, four-, and three-viroid combinations. Antagonistic interactions between CEVd and CVd-III or CBLVd and CVd-III were revealed over the years with consistent significance. The antagonistic interaction between CEVd and CVd-IV was highly significant over the years when additional viroids were present; however, this antagonism appeared much later in the case of an exclusive interaction. HSVd and CVd-IV showed a consistent and significant synergistic interaction on yield only when both viroids were exclusively present. These results demonstrate antagonistic or synergistic relationships between citrus viroids depending on the viroid mixtures present in the host.     

苹果壳色单隔孢溃疡病菌的适生区预测

苹果壳色单隔孢溃疡病菌(Botryosphaeria stevensii)是一种寄主十分广泛的进境植物检疫性真菌,在我国尚无分布。近年来,我国口岸多次截获该病菌。为更好地实现对该病菌的针对性检疫防控,本研究采用DIVA-GIS软件对该病菌在我国的潜在适生区进行了预测,并对其适生区内寄主情况进行了深入分析。研究结果表明,苹果壳色单隔孢溃疡病菌在我国的适生区域较为广泛,主要分布在我国华东、华北和华中地区;该病菌在其适生区域内存在大量寄主,尤其是水果类作物,林木寄主也有较多分布。因此,该病菌一旦传入我国,极可能造成十分严重的经济损失,值得高度警惕。本文最后提出了针对苹果壳色单隔孢溃疡病菌的风险防控建议。     

Spatio-temporal patterns of pre-harvest brown rot epidemics within individual peach tree canopies

Tree canopies are architecturally complex and pose several challenges for measuring and characterizing spatial patterns of disease. Recently developed methods for fine-scale canopy mapping and three-dimensional spatial pattern analysis were applied in a 3-year study to characterize spatio-temporal development of pre-harvest brown rot of peach, caused by Monilinia fructicola, in 13 trees of different maturity classes. We observed a negative correlation between an index of disease aggregation and disease incidence in the same tree (r?=??0.653, P?<?0.0001), showing that trees with higher brown rot incidence had lower aggregation of affected fruit in their canopies. Significant (P?≤?0.05) within-canopy aggregation among symptomatic fruit was most pronounced for early-maturing cultivars and/or early in the epidemic. This is consistent with the notion of a greater importance of localized, within-tree sources of inoculum at the beginning of the epidemic. Four of five trees having >10 blossom blight symptoms per tree showed a significant positive spatial association of pre-harvest fruit rot to blossom blight within the same canopy. Spatial association analyses further revealed one of two outcomes for the association of new fruit rot symptoms with previous fruit rot symptoms in the same tree, whereby the relationship was either not significant or exhibited a significant negative association. In the latter scenario, the newly diseased fruit were farther apart from previously symptomatic fruit than expected by random chance. This unexpected result could have been due to uneven fruit ripening in different sectors of the canopy, which could have affected the timing of symptom development and thus led to negative spatial associations among symptoms developing over time in a tree.     

Colletotrichum acutatum and Colletotrichum nymphaeae causing blossom blight and fruit anthracnose on olives in southern Brazil

European Journal of Plant Pathology - Olive (O. europaea L.) is an expanding crop in the south of Brazil. Blossom blight and typical anthracnose symptoms on fruit were observed in olive trees in an...     

河北省果树盲蝽种类组成及其发生规律

系统调查了河北省不同果树种植生态区域内盲蝽种类组成和种群发生规律。调查结果表明,河北省不同果树生态区域内,盲蝽主要发生种类均为绿盲蝽。调查结果还揭示了绿盲蝽在棉花-果树生态区、粮食-果树生态区和果树单独种植区内的种群动态和发生规律。基于以上调查结果,讨论了河北省不同果树种植生态区域内的盲蝽分区治理策略。     

Spatiotemporal characterization of citrus postbloom fruit drop in Brazil and its relationship to pathogen dispersal

Citrus postbloom fruit drop (PFD) is caused by Colletotrichum acutatum and C. gloeosporioides. These pathogens attack the flowers and cause premature fruit drop and the retention of fruit calyces. This study was designed to characterize the spatial and temporal dynamics of PFD in commercial citrus‐growing areas to better understand the disease spread. Experiments were carried out in three young orchards (500 trees each) in two municipalities in Sao Paulo State, Brazil. Symptoms of PFD on the flowers and presence of persistent calyces were assessed in each of three orchards for three years. Logistic, Gompertz and monomolecular models were fitted to the incidence data over time from the trees with symptoms. The spatial pattern of diseased trees was characterized by a dispersion index and by Taylor′s power law. An autologistic model was used for the spatiotemporal analysis. The logistic model provided the best fit to the disease incidence data, which had a fast progress rate of 0·53 per day. During the early epidemic of PFD, the spatial pattern of diseased trees was random, which suggested that inoculum spread was due to mechanisms other than rain splash. As the disease incidence increased (up to 12·6%), the spatial pattern of diseased trees became aggregated. The rapid rate of disease progress and the distribution of PFD suggest that dispersal of the pathogen is possibly related to a mechanism other than splash dispersal, which is more typical of other fruit diseases caused by Colletotrichum spp.     

Comparison of four techniques for plum pox virus detection

Journal of Plant Diseases and Protection - Twenty-four stone fruit trees showing typical symptoms of plum pox virus (PPV) were tested for PPV using ELISA, RT-PCR, real-time RT-PCR and RT-LAMP. The...     

European stone fruit yellows phytoplasmas associated with a decline disease of apricot in southern England

Phytoplasmas detected by fluorescence microscopy and polymerase chain reaction (PCR) have been discovered infecting Prunus trees at a site in south-east England. The pathogens were detected in tissue samples taken in autumn and also in spring. The symptoms in infected trees varied from severe decline to absence. PCR experiments using group-specific primers to amplify regions of the 16S RNA gene indicated that the phytoplasmas are similar to European stone fruit yellows isolates occurring in southern and eastern Europe. This is the first record of phytoplasmas in Prunus species in the UK. The origin of the infection is unknown. The implications of this new disease for the fruit industry are discussed.