Host range and phytotoxicity of <Emphasis Type="Italic">Stemphylium solani</Emphasis>, causing leaf blight of garlic (<Emphasis Type="Italic">Allium sativum</Emphasis>) in China

Since 2004, a new leaf blight disease on garlic of high severity has been observed in Dangyang County, Hubei province, China. Initial symptoms consisted of multiple, small, irregular to oval, white leaf spots, which enlarge to produce sunken purple lesions, sometimes surrounded by a bright yellow margin. As the disease progressed, lesions expanded and merged, resulting in withering of leaf tips. After isolation and pathogenicity testing, the causal agent of leaf blight of garlic was identified as Stemphylium solani from cultural and morphological characteristics, and subsequent analysis of the internal transcribed spacer region of ribosomal DNA. When fungal plugs of two S. solani isolates were inoculated onto 11 garlic cultivars and 20 other crop species, leaf spots appeared on all inoculated plants, but two garlic cultivars (Qingganruanye and Ruanruanye) and three crop species (Capsicum annuum, Brassica napus and Amaranthus mangostanus) showed the smallest leaf spots. In cross-inoculation experiments, no indications of host specificity were observed, but S. solani isolated from garlic was generally the most virulent on five plant species, while the isolate from leek (Allium odorum) was generally the least virulent. Toxicity testing of the crude culture filtrates indicated that garlic isolates produced toxin(s) that were not heat-labile and induced different levels of phytotoxicity toward various garlic cultivars and crops.     

‘Instant’ Bordeaux and Burgundy Mixtures

Four annual experiments with garlic (Allium sativum) were established in fields naturally infested with Sclerotium cepivorum, causal agent of garlic white rot, to investigate the effect of time of planting on yield. Initial stands were unaffected by time of planting. Final stands and yields were highest when garlic was planted approximately 1 month earlier (28 January-15 February) when soils were warmer than at the traditional time of planting (15 March-15 April). When garlic was planted at the traditional time, final stands and yields were reduced 56-92% primarily from the attack of S. cepivorum. A 100% loss in yield occurred in some crops planted in cool soils in late March. With an early planting (15 January), final stands were similar to the plantings of 28 January and 15 February, but yields were reduced by half because of a much lower mean weight of the harvested bulbs. In a late planting (15 May), the final stand was 75% lower with correspondingly lower yield than that obtained with the early plantings. The largest bulbs (21.6 g) were obtained from the planting on 28 February; however, the yields from this planting were reduced by half from the planting 2 weeks earlier because of the 50% reduction in final stand. Early planting of garlic is recommended as an important management strategy to avoid white rot in areas with soils infested with sclerotia of S. cepivorum.     

Comparison of Physical, Chemical and Biological Methods of Controlling Garlic White Rot

Treatment of garlic cloves with tebuconazole (at 1ml of Folicur 25% l^–1) achieved a significant reduction in the rate of disease progress and the final incidence of plant death by Sclerotium cepivorum: garlic yields were improved. Although soil solarization provided the best control of garlic white rot, bringing soil populations of S. cepivorum to negligible levels, similar levels of disease control and garlic yields were achieved when tebuconazole was sprayed to stem bases of plants grown from cloves also treated with tebuconazole. This double treatment almost doubled the yield compared with untreated plants and significantly increased bulb quality under high disease pressure conditions. Soil solarization was also highly effective in a second consecutive crop of garlic, with significant improvements in yield and garlic quality. In contrast, lower levels of disease control were obtained when selected isolates of Trichoderma harzianum and Bacillus subtilis were applied to the soil and cloves respectively.     

大蒜与黄瓜轮作控制黄瓜疫病及其化感作用初探

传统农业种植中常将目标作物与化感作物轮作控制土传病害,但对化感作物控病机制研究较少。本文研究了温室大蒜与黄瓜轮作对黄瓜疫病的控制效果,并进一步研究了大蒜组织挥发物和浸提液对甜瓜疫霉Phytophthora melonis及黄瓜种子萌发的影响,以期为利用大蒜与黄瓜轮作控制黄瓜疫病提供理论指导。结果表明,大蒜与黄瓜轮作可以有效降低黄瓜疫病的发生;大蒜不同组织挥发物和浸提液对P.melonis的各生长阶段都表现出显著的抑菌活性,其中蒜瓣的抑菌活性最强,挥发物(紫皮蒜/白皮蒜)在含量0.5 g/皿时对菌丝生长的抑制率均为100%;蒜瓣浸提液(紫皮蒜/白皮蒜)在浓度1.67 mg/mL时对菌丝生长的抑制率分别为32%和45%;在浓度0.25 mg/mL时对游动孢子萌发的抑制率分别为98%和53%。另外,大蒜挥发物和浸提液在低浓度或含量对黄瓜种子的萌发并无显著抑制效果,但在中高浓度或含量会表现出延缓生长的现象。综上所述,大蒜不同组织产生和释放的化合物对P.melonis具有抑制活性,在生产上可以利用大蒜或大蒜秸秆与黄瓜轮作控制黄瓜疫病的发生。     

Aetiology of leaf spot of garlic and onion caused by Stemphylium vesicarium in Spain

Surveys between 1989 and 1993 in the major garlic production areas of Spain identified a new leaf spot disease, characterized by white and purple lesions followed by extensive necrosis. Isolation and pathogenicity tests with fungal isolates taken from these spots indicated that Stemphylium vesicarium was the causal agent. Pseudothecia of the teleomorph stage, Pleospora sp., were found on leaf debris from affected plants. Inoculation of garlic and onion plants with residues carrying mature pseudothecia, or with ascospore suspensions obtained from the pseudothecia, resulted in the development of white and purple leaf spots. Wetness periods longer than 24 h were required for symptom development under controlled conditions. Isolates of S. vesicarium from garlic, onion and asparagus caused disease in all three hosts. In garlic, cv. Blanco de Vallelado was most susceptible, while lines B4P17 and B6P1, and cvs Iberose and Golourose were less susceptible to the disease.     

番茄斑萎病毒系统侵染我国大蒜

番茄斑萎病毒Tomato spotted wilt tospovirus(TSWV)是严重危害世界经济作物的一种病毒,寄主范围广泛。我们在研究中发现番茄斑萎病毒能侵染我国大蒜Allium sativum L.。利用摩擦接种法将TSWV接种到健康大蒜上,结果显示:接种14 d后大蒜新生叶片出现褪绿和白色斑点症状。ELISA检测显示大蒜叶片汁液与TSWV的单克隆抗体产生血清学反应,采用TSWV N基因的引物对大蒜叶片总RNA进行RT-PCR,结果扩增出约800 bp的条带,在NCBI上BLAST显示与TSWV YN5576的同源性最高,为98.52%。这些数据表明番茄斑萎病毒系统侵染我国大蒜。     

Aetiology of garlic rot,an emerging disease in France

The incidence of garlic rot has constantly increased in France since the early 2000s. To set up an efficient method of garlic protection against this disease, we have clarified its aetiology. This was achieved by surveying garlic from the two main French basins of garlic production over 3 years. Fungi were isolated from 5,493 garlic cloves belonging to pink, purple, and white garlic types. Sequencing of the translation elongation factor 1α gene of 1,171 strains revealed that 94% of the strains belonged to the species Fusarium proliferatum and 6% belonged to F. oxysporum. The pathogenicity of both species on garlic was confirmed by artificial inoculations and reisolations. There was significantly more F. oxysporum in garlic cloves with symptoms coming from the southeast basin (9.44%) than from the southwest basin (2.76%). This study confirms that garlic rot is present in pink, purple, and white types. However, pink type garlic harbours F. oxysporum significantly less frequently (1.59%) than white (9.39%) and purple (7.34%) types. Sequencing of rpb1, rpb2, ITS, and IGS regions of a subsample of strains revealed that there is little genetic diversity in the French population of F. proliferatum.     

取食不同寄主植物对韭菜迟眼蕈蚊幼虫药剂敏感性的影响及其生化机制

采用浸渍法研究了分别取食韭菜、大葱、圆葱和大蒜的韭菜迟眼蕈蚊4龄幼虫对大蒜油、苦参碱和辛硫磷的敏感性,用生化分析法测定了敌敌畏和大蒜油对幼虫体内乙酰胆碱酯酶和主要代谢酶活性的影响.结果表明:大蒜油对取食韭菜、大葱、圆葱和大蒜4龄幼虫的LC50分别为825.14、1202.2、1274.3和1412.4mg/L;辛硫磷分别为0.5437、1.1921、1.7713和1.9224mg/L,两种药剂对取食大蒜和圆葱幼虫的毒力较取食韭菜的差异显著.取食大蒜和圆葱的幼虫较取食韭菜的其体内乙酰胆碱酯酶活力降低,羧酸酯酶的活力明显提高,谷胱甘肽-S-转移酶的活力也有一定提高.寄主植物所含的硫醚类化合物对乙酰胆碱酯酶和代谢酶的诱导或抑制可能是引起药剂敏感性差异的主要原因.     

In vivo anti-mildew activity of essential oils against downy mildew of sunflower caused by PLASMOPARA HALSTEDII

European Journal of Plant Pathology - Commercial essential oils (EO) obtained from different parts of black cumin (N. sativa), mustard (S. nigra), St. John’s wort (H. perforatum), garlic (A....     

Morphology, life cycle biology, and DNA sequence analysis of rust fungi on garlic and chives from california

ABSTRACT In the late 1990s, commercial garlic fields in California (CA) were devastated by an outbreak of rust caused by Puccinia allii. We compared collections of the pathogen from garlic (Allium sativum) and chives (A. schoenoprasum) in central CA and Oregon (OR) to collections from garlic and leek (A. porrum and A. ampeloprasum) in the Middle East. Teliospores from the CA and OR collections were smaller in length, width, and projected cross-sectional area compared with collections from the Middle East. CA and OR collections had a shortened life cycle, in which pycnia and aecia were not formed. Germinating teliospores produced a two-celled promycelium, resulting in two basidiospores, each initially with two nuclei, indicating that this rust was homothallic. In addition, the morphology of the substomatal vesicles was different between the CA-OR (fusiform) and the Middle Eastern (bulbous) collections. DNA sequence analysis of the nuclear ribosomal internal transcribed spacer region showed that the CA and OR rust collections formed a well-supported cluster distinct from the Middle Eastern and European samples. These results suggest that the rust on garlic and chives in CA and OR is a different species than the rust fungus on garlic and leek in the Middle East.     

干草原区植被保护支持技术研究绿色添加剂—大蒜(Allium sativum)对肉牛增重影响的研究

大蒜是一种植物鳞茎 ,作为肉牛饲料添加剂尚未见报道。本文研究的目的是 :研究大蒜对肉牛增重的影响。试验选用西门塔尔杂交后代公牛 3 8头其中 3 5头牛随机分为七组 ,大蒜组 A( 50 g/ d.头 )、D( 1 0 0 g/ d.头 )、F( 1 50 g/ d.头 ) ;大蒜素组 C( 0 .2 g/ d.头 )、E( 0 .4g/ d.头 )、G( 0 .6g/ d.头 ) ;对照组。试验采用完全拉丁方设计。试验结果表明 :1 .大蒜在添加 74.6g/ d.头左右 ,对肉牛增重有明显的促进作用 ,Y=-0 .0 0 2 2 x2 +0 .3 2 8x+2 8.3 2 ,R2 =0 .972 8( Y为增重 ,X大蒜用量 )。 2 .当大蒜素添加量为 0 .3 5g/ d.头时肉牛体增重最高 ,y=-92 .5x2 +65.4x+2 7.3 3 R2 =0 .91 96( Y为增重 ,X大蒜素用量 )。 3 .大蒜促进肉牛增重的主要成分是大蒜素     

Crude garlic extract significantly inhibits replication of grapevine viruses

Efforts to control viral diseases of grapevine include the production of certified material and development of virus-resistant transgenic grapevines. However, effective antiviral agents, once the viruses have infected the plants, are still lacking. This study shows that a crude garlic extract has significant antiviral activity against grapevine viruses. Replication of grapevine leafroll-associated virus 2 (GLRaV-2) was obviously inhibited in grapevine cv. Cabernet Sauvignon calli treated with diluted (1:100) garlic extract. The relative RNA levels of GLRaV-2 and grapevine fleck virus (GFkV) in cv. Summer Black grapevine in in vitro-grown plantlets 10 days after treatment with diluted (1:100) garlic extract were about 22% and 20%, respectively, of that in controls. The viral RNA accumulation of GLRaV-2, GFkV, grapevine virus A (GVA), grapevine fanleaf virus (GFLV) and grapevine rupestris stem pitting-associated virus (GRSPaV) in field-grown grapevine cv. Centennial Seedless plants sprayed with diluted (1:100) garlic extract were about 31–40%, 26–38%, 18–31%, 17–42% and 15–18%, respectively, of that in controls. Moreover, the garlic extract treatment led to a significant decrease in viral RNA accumulation of GLRaV-3, GLRaV-2, GVA, GFkV, GFLV, GRSPaV and grapevine Pinot Gris virus in pot-grown grapevine cv. Shine Muscat plants, and viral disease symptoms in these plants were obviously attenuated. In addition, this extract significantly induced expression of pathogenesis-related protein genes and stimulated activity of antioxidant enzymes in grapevines. Taken together, these results indicate that the crude garlic extract acts as a significant inhibitor against a broad range of grapevine viruses.     

贮藏期蒜薹表面真菌群落组成分析

蒜薹作为一种传统常年供应的蔬菜深受喜爱,由于贮存时间长,贮存过程中会有多种真菌产生,导致蒜薹失去经济价值。本文通过提取贮藏期蒜薹表面真菌的基因组DNA,经Illumina平台对7个样本的ITS扩增子进行测序,共获得2 418 016条raw reads,51个OTUs。通过OTU物种注释和物种丰度聚类,优势真菌属组成为:青霉菌属Penicillium 81.08%,未知子囊菌15.13%,耐冷酵母Mrakia 1.74%,小球壳属Mycosphaerella 1.02%。青霉菌是贮藏蒜薹后期表面的主要真菌。     

Effect of volatiles and crude extracts of different plant materials on egg viability ofmaruca vitrata andclavigralla tomentosicollis

The effect of volatiles and aqueous extracts of black pepper,Piper guineense; neem seed,Azadirachta indica; garlic bulb,Allium sativum; and onion bulb,Allium cepa on egg viability ofMaruca vitrata Fab. (Lepidoptera: Pyralidae) andClavigralla tomentosicollis Stål (Heteroptera: Coreidae) was evaluated in laboratory experiments. Compared with the other treatments, volatiles of black pepper and garlic bulb were superior in reducing hatch of freshly laid (12-h-old) eggs of both species of insects. Volatiles of onion bulb and neem seed had no effect on egg hatch. When aqueous extracts of the various plant materials were tested at 5%, 10% and 15%, extracts of black pepper, neem seed and garlic bulb caused a severe reduction in egg hatch, with black pepper and garlic bulb providing the highest reduction at all concentrations tested in both insects. When black pepper and garlic bulb were compared at 5% for their activity in relation to egg age, the effect of black pepper decreased with increasing egg age but the performance of garlic was consistent across the various age groups tested in both insects. This result is indicative of the potential of using these plant materials and especially garlic for the management ofM. vitrata andC. tomentosicollis.     

Field evaluation of commercial plant extracts against Drosophila suzukii (Diptera: Drosophlidae) in raspberry

Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) was detected in 2008 in southern Europe and North America and it has spread rapidly throughout the two continents mainly affecting thin-skinned berries and stone fruits which constitute an important, economic and social driver in these regions. This study analyzes the potential control ability of four commercial plant-derived extracts, namely Sophora flavescens (shrubby sophora), Cinnamomum zeylanicum (cinnamon), Capsicum frutescens (chili) and Allium sativum (garlic), against D. suzukii, under raspberry high tunnel field conditions. Extracts were applied in a randomized complete block design using spinosad as positive control. As expected, spinosad treatment resulted in a satisfactory control, reducing significantly the number of larvae and adults emerged from treated fruits even ten days after application. Sophora flavescens extract produced a significant reduction of 60.7% in emerged adults, with no reduction in the number of larvae, six days after application. In addition, garlic extract caused significant reduction in the mean number of larvae (over 50%) and emerged adults (over 48%) six days after application. These findings suggest that garlic and S. flavescens affect egg viability and/or larvae development. Tentative explanations about the variability of the results and possible benefits of repetitive treatments are discussed.     

大蒜对福寿螺的控制效果及其对水稻苗的影响

在实验室和盆栽条件下研究了大蒜植株、蒜瓣(鳞茎)和大蒜素对福寿螺和水稻苗生长的影响。结果表明,大蒜植株、蒜瓣中的大蒜素对福寿螺均具有致死效果,大蒜素只是大蒜植株和蒜瓣中致福寿螺死亡的物质之一。福寿螺在大蒜素溶液中出现逃逸现象,在0.025和0.012 5g/mL浓度下全部逃逸,而在0.05g/mL浓度下逃逸率仅为60%,死亡率达40%。福寿螺在大蒜种植密度为9、14、18株/盆时,含有大蒜根分泌物的盆中均出现逃逸现象,密度越大逃逸越快,数量越多,而在大蒜植株混入土壤的盆中,密度为9株/盆中的福寿螺全部逃逸,密度为14、18株/盆中则只有部分逃逸,没有逃逸的福寿螺出现死亡或失去取食能力。试验浓度下的大蒜素溶液对水稻生长影响较小,0.012 5g/mL的大蒜素溶液对水稻还有促进作用。在种植不同密度大蒜的盆中,仅混合大蒜植株,密度为18株/盆的处理中水稻的分蘖数有显著的减少(P0.05),其他无论是含有根分泌物还是混合大蒜植株的盆中,水稻生长均未受到不利的影响。表明大蒜植株和蒜瓣中的大蒜素对福寿螺具有抑制取食为害、甚至毒杀的效果,在对福寿螺有效的浓度下对水稻苗的生长没有不利影响。     

大蒜根系分泌物对烟蚜的生物活性

为了探索大蒜根系分泌物粗提物及其四种成份对烟蚜的影响，分析大蒜在烟田套种生态系统中对烟蚜的控制作用，在室内利用固体琼脂培养法培养、分离了大蒜根系分泌物粗提物，并测定了该分泌物粗提物及其四种成份（邻苯二甲酸二丁酯、2，6-二异丙基苯酚、二烯丙基二硫和2，6-二叔丁基对甲酚）对烟蚜的忌避、触杀等生物活性。大蒜根系分泌物粗提物对烟蚜有显著的忌避、触杀活性。大蒜根系分泌物粗提物为4 g/mL时，对烟蚜的忌避活性较好，忌避率在75.93%～80.56%，且对烟蚜的触杀活性也较好，其死亡率在92.22%～96.67%。大蒜根系分泌物4种成份对烟蚜也有显著的忌避、触杀活性。2，6-二异丙基苯酚对烟蚜的忌避活性较好，其忌避率在93.65%～100.00%；邻苯二甲酸二丁酯和2，6-二异丙基苯酚对烟蚜触杀活性较好，其死亡率在83.33%～92.22%。4种成份对烟蚜的忌避活性由强至弱顺序为2，6-二异丙基苯酚，二烯丙基二硫，邻苯二甲酸二丁酯，2，6-二叔丁基对甲酚；而触杀活性由强至弱顺序为2，6-二异丙基苯酚，邻苯二甲酸二丁酯，2，6-二叔丁基对甲酚，二烯丙基二硫。以上结果表明，大蒜根系分泌物粗提物及其4种成份对烟蚜均具显著的忌避、触杀作用，这为研制含大蒜根系分泌物或其4种成份的植物保护剂和间作套种大蒜等绿色防控措施防控烟蚜提供科学参考。     

镰刀菌对大蒜根系分泌物的敏感性与其致病力相关分析

试验采用菌丝生长速率法测定了大蒜根系分泌物对3种供试植物病原镰刀菌的抑菌活性, 并进一步分析了18株从腐烂蒜瓣上分离的尖孢镰刀菌和12株从小麦赤霉病样分离的禾谷镰刀菌对大蒜根系分泌物的敏感性及致病力之间的关系。研究结果表明, 大蒜根系分泌物对供试镰刀菌均具有抑制活性, 但从腐烂蒜瓣上分离的尖孢镰刀菌对根系分泌物的敏感性低于其他菌株。致病力分析结果表明, 供试的18株尖孢镰刀菌均能使蒜瓣发病, 但致病力与其对根系分泌物的敏感性无明显相关性; 供试的禾谷镰刀菌中对根系分泌物不敏感的4株菌株能侵染蒜瓣, 但敏感性高的菌株不能侵染蒜瓣, 且根系分泌物对禾谷镰刀菌的抑制率与禾谷镰刀菌致病力之间呈显著的负相关。这表明大蒜根系分泌抑菌物质是根系抵御镰刀菌侵染的重要机制, 但一些菌株能对根系分泌物产生抗性, 从而侵染大蒜。综上所述, 大蒜根系分泌物对镰刀菌具有抑制活性, 可以利用大蒜和其他作物间作或轮作控制镰刀菌枯萎病的发生和蔓延, 但长期利用大蒜轮作或间作控制土传病害可能面临镰刀菌对大蒜根系分泌物产生抗性, 导致防效降低的风险。     

大蒜根系分泌物对烟草青枯病的影响

为探讨大蒜根系分泌物对烟草青枯病菌的抑菌活性,采用抑菌圈法和盆栽试验研究了大蒜根系分泌物及其主要成分对烟草青枯病的影响。结果表明：大蒜根系分泌物浓度为1g/mL时,对烟草青枯病菌抑制效果最好,其抑菌率为53.67%。大蒜根系分泌物4种成分的抑菌效果由强到弱依次为：2,6-二异丙基苯酚>二烯丙基二硫>2,6-二叔丁基对甲酚>邻苯二甲酸二丁酯。其中,2,6-二异丙基酚对烟草青枯病菌的抑制作用最强,在1和5mmol/L时的抑菌率分别为99.66%和100.00%;在盆栽试验中也具有较好的防治效果,接种后7 d和14 d后,其防效分别为34.75%和31.35%。因此,大蒜根系分泌物及其成分均对烟草青枯病有明显的抑制作用。本研究揭示了大蒜作为轮作或间作作物对烟草青枯病的防控机理,以及大蒜根系分泌物和2,6-二异丙基酚作为烟草青枯病防治剂的潜力。     

Reduced sclerotial viability of Stromatinia cepivora and control of white rot disease of onion and garlic by means of soil bio-solarization

The suppressive effects of soil bio-solarization, which is a new method of soil disinfestation that combines soil bio-fumigation with soil solarization, against the sclerotial viability of Stromatinia cepivora and the subsequent control of white rot disease of onion and garlic were evaluated. Soil was bio-fumigated with fresh amendments of cow manure, chicken manure, horse manure, cruciferous plant residues, or Allium waste, at 30,000 kg/ha. After bio-fumigation, the soil was irrigated and covered with a 200 μm transparent plastic sheet for 60 days. Plots that received fresh amendment and remained uncovered and untreated served as controls. Solarization alone increased the maximum soil temperature to 55.3 °C, 50.3 °C and 46.3 °C at 10, 20, and 30 cm depths, respectively, which led to significant reductions (98.0%, 89.3%, and 62.7%, respectively) in the sclerotial viability of S. cepivora. Soil bio-solarization with cruciferous plant residues or Allium waste resulted in the strongest negative effects on the sclerotial viability of S. cepivora, with reductions of 100.0%, 98.7%, and 87.3% or 100.0%, 99.3%, and 87.7%, at 10, 20, and 30 cm depths, respectively. Compared to the non-treated control, these treatments significantly reduced the incidence of white rot disease in onion and garlic, which led to increases in onion and garlic yield in fields that were heavily infested by S. cepivora.