A rare leaf spot disease of Scorzonera hispanica,caused by Alternaria scorzonerae (Aderhold) comb. nov.

Samenvatting In 1982 is in Nederland op twee plaatsen in Noord-Brabant bij schorseneer een bladvlekkenziekte geconstateerd die werd veroorzaakt door een schimmel die te boek staat alsSporidesmium scorzonerae Aderhold (syn.Macrosporium tau-saghyzianum Zerova). Het betreft een zeldzaam optredende ziekte, die niet eerder buiten Oost-Europa bij de produktieteelt van schorseneren is aangetroffen. Onderzoek naar de morfologie van de schimmel wees uit dat deze behoort tot Alternaria sect. Noncatenatae. Derhalve werd voor het pathogeen de nieuwe combinatieAlternaria scorzonerae (Aderhold) Loerakker geïntroduceerd.     

Bacterial leaf blight of strawberry (Fragaria (x) ananassa) caused by a pathovar of Xanthomonas arboricola, not similar to Xanthomonas fragariae Kennedy & King. Description of the causal organism as Xanthomonas arboricola pv. fragariae (pv. nov., comb. nov.)

A new bacterial disease of strawberry is described. This disease, called bacterial leaf blight of strawberry, is characterized by dry, brown necrotic leaf spots and large brown V-shaped lesions along the leaf margin, midrib and major veins. Symptoms are different from angular leaf spot of strawberry caused by the bacterium Xanthomonas fragariae . Strains of the bacterial leaf blight pathogen were characterized in a polyphasic approach by biochemical tests, fatty acid analysis, protein electrophoresis, serology, PCR, pigment analysis, ice-nucleation activity, AFLP analysis, DNA:DNA hybridization, pathogenicity and host range tests, and compared with a number of reference strains of X. fragariae and other Xanthomonas species. Bacterial leaf blight strains formed a homogeneous group in all tests, completely different from X. fragariae . They were the only strains causing leaf blight of strawberry upon artificial inoculation into strawberry. Fatty acid and protein electrophoretic analysis showed that the strains belong to the phenon X. campestris ( sensu latu , including pathovars now classified as belonging to X. arboricola ). AFLP analysis and DNA:DNA hybridization further clarified their taxonomic position as belonging to X. arboricola. The name X. arboricola pv. fragariae is proposed for the bacterium causing leaf blight of strawberry with strain PD2780 (LMG 19145) as pathovar type strain. Criteria for routine identification are given and the taxonomic status is discussed.     

Description of the Bacterium Causing Blight of Leek as Pseudomonas syringae pv. porri (pv. nov.)

ABSTRACT Forty bacterial strains isolated from leek blight (Allium porrum) in France and other countries were studied by conventional biochemical methods, serological reactions, numerical taxonomy, DNA-DNA hybridization, and ice nucleation activity, as well as by pathogenicity on leek and other host plants. They were compared with reference strains of Pseudomonas, mainly pathotype strains of P. syringae pathovars and strains of P. syringae pv. syringae isolated from various host plants including onions. Leek strains sorted with P. syringae species (sensu lato) by LOPAT tests (production of levan-sucrase, oxidase, pectinase, arginine dihydrolase, and hypersensitive reaction on tobacco). Leek strains were pathogenic to leek and produced symptoms identical to those observed in the field. They were the only strains in our study that could cause blight of leek. Thus, our results justify the creation of a new pathovar. Leek strains constituted a highly homogeneous DNA group and a discrete phenon by numerical taxonomy, and they belonged to O-serogroup POR. The name of P. syringae pv. porri is proposed for the bacterium causing leek blight. Criteria for routine identification are presented and taxonomic status is discussed.     

Life-cycle of the cestode Wardium calumnacantha (Schmidt, 1963) comb. n. (Hymenolepididae) from common snipe, Gallinago gallinago (L.)

Post-embryonic development of the cestode Wardium calumnacantha (Schmidt, 1963) comb. n., a parasite of common snipe, was studied by experimental infection of the oligochaetes Neoscolex roseus Morev and Rhyacodrilus coccineus (Vejdovsky) carried out in Chukotka. The larvae of W. calumnacantha were ovoid and belonged to the morphological modification of cysticercoid-diplocyst. Two invaginations were observed during the larvogenesis. The first one occurred at the stage of scolexogenesis, when the body of larva was plunged into the external cyst formed by the walls of the primary cavity. Second invagination of the formed scolex and neck into the internal cyst was the final stage of cysticercoid formation.     

化学杂交剂GENESIS诱导普通小麦雄性不育效果研究

以 20个普通小麦品种为母本 ,采用二裂式裂区设计 ,研究了化学杂交剂 Genesis的诱导雄性不育效果和不同品种间的遗传差异 ,结果表明: 1)Genesis对普通小麦有良好的诱导雄性不育效果 ,供试的 20个品种的不育率为99.2 %～100% ,杂交率为 83%～100% ,反应度为 2～7级; 2)不同施用剂量间的杀雄效果存在显著差异 ,以3kg/hm2 的剂量最优 ,其不育率近100 %; 3)不同喷药时期 (Feeke`s stage8.0和9.0)间差异不显著 ,适喷期 7d左右。根据试验结果 ,还讨论了Genesis的药害问题与适喷期小麦发育的形态指标。     

Pewenomyces kutranfy gen. nov. et sp. nov. causal agent of an important canker disease on Araucaria araucana in Chile

Araucaria araucana, (commonly referred to as araucaria, pewen, or monkey puzzle tree) is an ancient conifer endemic to the Chilean and Argentinian mountain ranges where it has a sacred relevance to indigenous communities. During 2015, a serious disease was noticed on trees of all ages in most of the natural distribution of this iconic tree. Four areas were surveyed, and the most important symptoms of the disease were cankers on branches and stems resulting in copious resin exudation. Trees were monitored for a period of two years and isolations were made from the cankers. Field observations showed that the disease typically begins on the leaves or at the leaf bases and progresses downwards to initiate cankers that can girdle branches or stems within a two-year period. Black ascomata, resembling those of Caliciopsis species previously described from A. araucana, were consistently found developing in the cankers from which isolations were made. Phylogenetic analyses of the ITS, nucSSU, and nucLSU gene regions showed that the fungus resides in the Coryneliaceae but is distinct from other genera in that family. The morphological characteristics and phylogenetic position of the fungus show that it represents a new genus and species, described here as Pewenomyces kutranfy gen. nov. et sp. nov. Pathogenicity trials on trees under field conditions confirmed that this newly described fungus is able to cause cankers on A. araucana similar to those found under natural conditions.     

Phytotoxic activity of Chinese violet (Asystasia gangetica (L.) T. Anderson) and two phytotoxic substances

Chinese violet (Asystasia gangetica (L.) T. Anderson) is a perennial invasive weed belonging to Acanthaceae. Leaves of this weed have been suggested to possess phytotoxic activity. However, phytotoxic substances in this weed have not yet been reported. Therefore, the present study investigated phytotoxic activity of Chinese violet extracts and phytotoxic substances. The extracts of Chinese violet leaves inhibited the root and shoot growth of cress, lettuce, alfalfa, barnyard grass, ryegrass, and timothy, where the level of inhibition increased with increasing extract concentrations. Bioassay‐guided separations of the extracts led to isolation of two phytotoxic substances, indole‐3‐carboxaldehyde and (6R,9S)‐3‐oxo‐α‐ionol. Indole‐3‐carboxaldehyde significantly inhibited the root and shoot growth of cress at concentrations ≥100 and 30 μmol L^?1, respectively, and concentrations of the substance required for 50% growth inhibition were 210 and 127 μmol L^?1 for cress roots and shoots, respectively. The other substance, (6R,9S)‐3‐oxo‐α‐ionol, was reported to have strongly inhibited cress roots and shoots. The present results suggest that Chinese violet contains two phytotoxic substances indole‐3‐carboxaldehyde and (6R,9S)‐3‐oxo‐α‐ionol, and those substances may play an important role in the phytotoxic activity of Chinese violet.     

葡萄白腐病(Coniothyrium diplodiella(Speg.)Sacc.)的研究——Ⅱ、葡萄白腐病田间侵染规律的初步探讨

葡萄白腐病菌侵染的主要条件是伤口和充分潮湿。对葡萄的任何绿色组织,通过伤口,都能发生侵染。在高湿度环境下,或在叶片吐水之际,水孔能成为侵染的途径。在葡萄穗上,它们是不可能作为伤口被肉眼分辨出来的,然而穗梗上的自然伤口足够为病菌所入侵。白腐病菌的孢子萌发和入侵,是与潮湿密切相关的。土壤由于下雨或灌溉而充分湿润,可由下列两条途径引起侵染:(1)水膜凝聚引起营养物质外溢,从而促使孢子萌发,以至进一步入侵。(2)由于葡萄的根压增高而引起叶片吐水,给病菌提高水、营养物质的供应量,导致入侵。     

Colletotrichum carthami comb. nov., an anthracnose pathogen of safflower, garland chrysanthemum and pot marigold, revived by molecular phylogeny with authentic herbarium specimens

Authentic herbarium specimens of Gloeosporium carthami and G. chrysanthemi as well as live Colletotrichum strains from Carthamus tinctorius, Chrysanthemum coronarium var. spatiosum, and Calendula officinalis were judged to be conspecific based on morphological and molecular phylogenetic analyses. Representative strains from three asteraceous plants were demonstrated by inoculation tests to possess specific pathogenicity to the host plants. We propose a new combination, Colletotrichum carthami, for the anthracnose pathogen of the asteraceous plants, designating our specimen of G. carthami as its epitype. We characterize the species, which differs from the closely related Colletotrichum simmondsii in its pathogenicity and molecular characteristics.     

Atripes paspali gen. et sp. nov. (Magnaporthaceae) causing take-all disease on Paspalum guenoarum in Brazil

In Brazil, Paspalum species are commonly used in sports lawns, landscape projects, and as forage for livestock. Paspalum guenoarum plants showing symptoms of take-all disease were observed in the state of Rio Grande do Sul, Brazil. The fungus Gaeumannomyces graminis is the only species reported associated with this disease on Paspalum. In recent years, new species of Gaeumannomyces have been proposed based on molecular studies, which demonstrated the existence of a species complex. Take-all affects rice and wheat, but the aetiology of this disease on P. guenoarum is still unknown; this work aimed to elucidate the aetiology of the take-all on P. guenoarum in Brazil and evaluate possible alternative hosts of agricultural importance. Based on combined phylogenetic analyses of ITS, LSU, TEF-1α, and RPB1 sequences, the fungal pathogen was identified as Atripes paspali gen. et sp. nov., which is proposed as a new genus in the Magnaporthaceae family. A representative isolate of A. paspali was inoculated on healthy P. guenoarum plants and reproduced the same symptoms of take-all observed in the field. Furthermore, this fungus is also able to cause take-all on wheat plants; temperature directly affected the incidence and development of the disease in wheat. Take-all on P. guenoarum is caused by A. paspali.     

A new combination for the causal agent of tea anthracnose: <Emphasis Type="Italic">Discula theae-sinensis</Emphasis> (I. Miyake) Moriwaki &; Toy. Sato,comb. nov.

The causal agent of tea anthracnose, Gloeosporium theae-sinensis, was transferred to Discula based on morphological and molecular reidentification using living cultures.     

半轮线虫属新种——拟中华半轮线虫Hemicriconemoides parasinensis sp. nov.的描述

 拟中华半轮线虫新种(Hemicriconemoides parasinensis sp. nov.)模式标本采集于辽宁省沈阳市沈阳农业大学校园的丁香(Syringa oblata)根际土中,在河南省安阳市安阳公园的小叶女贞(Ligustrum quihoui)根际土中也有分布。主要鉴别特征是虫体头区圆形,头环2个,第1头环略小于或等于第2头环,排泄孔位于肠的前端(Rex=29~33),体长中等,口针中等(76~86 μ m),体环数R值中等(96~110),卵巢单生前伸,受精囊长圆形,尾部宽圆锥形、尾端半球形圆;幼虫具指状的棘片,约12~16排,后翻;雄虫未见。该新种虫体形态特征与中国半轮线虫(H. sinensis Vovlas,1988),芒果半轮线虫(H. mangiferae Siddiqi,1961)和微小半轮线虫(H. minutus Esser,1960)相近似。     

苏云金杆菌高效培养基优选模型的研究

本研究设计一套“正交试验－浓度加倍－生物测定”新的培养基配方优选模型，获得了理想的高效培养基配方。采用７９００７号菌株和５号配方，用７吨发酵罐进行试验，平均发酵效价达２８８７×１０３ＩＵ／ｍｌ。实验结果表明，该方法是苏云金杆菌发酵培养基配方优选中十分简单、实用、快速的新途径