Gray Blight Research Articles

차나무 겹둥근무늬병의 발생소장 및 엽권 길항미생물 선발

차나무(Camellia sinensis O. Kuntze) 겹둥근무늬병의 발생소장을 2004년도 전남 보성군 보성읍 소재 전남농업기술원 보성차시험장에 식재되어 있는 야부기타 품종에서 조사하였다. 차나무 겹둥근무늬병은 6월말부터 발생하기 시작하여 7월말에 최대발병률을 나타내었다. 차나무의 엽권으로부터 차나무 겹둥근무늬병균에 대한 길항미생물을 분리하였으며, 차나무 겹둥근무늬병균에 대하여 가장 길항능력이 우수하고 차나무에는 병원성을 나타내지 않는 BD0310 균주를 겹둥근무늬병 방제용 길항미생물로 선발하였다. 선발된 균주는 배양적, 형태적, 생화학적 특성 조사와 16S rDNA염기서열 분석에 의하여 Bacillus subtilis 로 동정되었다. Disease progress of gray blight of tea (Camellia sinensis O. Kuntze) cv. Yabukita was investigated during the growing season of 2004 at Boseong Tea Experiment Station, Jeonnam Agriculture Research and Extension Service, Boseong, Jeonnam. The disease began to occur from late June and peaked in late July. Antagonistic bacteria against Pestalotiopsis longiseta, the causal pathogen of causing gray blight of tea plants were isolated from phylloplanes of tea plants. An isolate BD0310 which showed the strongest antifungal activity against the pathogen but nonpathogenic to tea plants was selected as a biocontrol agent for the gray blight. The isolate was identified as Bacillus subtilis based on its cultural, morphological, and biochemical characterization and 16S rDNA sequence analysis.

Resistance of Korean Tea Landrace Populations, to Tea Anthracnose, Tea Gray Blight and Tea Bacterial Shoot Blight

Resistance of Korean Tea Landrace Populations, to Tea Anthracnose, Tea Gray Blight and Tea Bacterial Shoot Blight

Phenotypes and Genotypes Related to Tea Gray Blight Disease Resistance in the Genetic Resources of Tea in Japan

The phenotypes related to tea gray blight resistance were evaluated by the artificial inoculation method in the accessions of tea germplasm preserved at the National Institute of Vegetable and Tea Science in Makurazaki, Kagoshima Prefecture. The genotypes of 453 plants including 89 main tea cultivars in Japan were also determined by using the parent-offspring genetic analysis of many cross combinations. A wide variation in the resistance of tea plants to tea gray blight was observed both in terms of phenotypes and genotypes. The majority of the Assam plants (Camellia sinensis var. assamica) showed a high level of resistance and very few variations, both in genotypes and phenotypes. The Japanese native plants (C. sinensis var. sinensis) showed a wider genetic diversity than any other groups of plants in the resistance to tea gray blight. Since many of the tea plants derived from other countries were highly resistant to the disease and harbored 2 Pl1 genes which confer a high level of resistance, they are very important materials for the breeding of cultivars that are resistant to the disease. The phenotype and genotype analysis was found to be very useful to identify doubtful cultivars.

Genetic Analysis of Tea Gray Blight Resistance in Tea Plants

Tea gray blight caused by Pestalotiopsis longiseta SPEGAZZINI is a severe disease in tea fields in Japan. The resistance of tea plants to the disease was found to be controlled by 2 independent dominant resistance genes Pl1 and Pl2, based on parent-offspring genetic analysis. There were 9 genotypes for resistance to P. longiseta in tea plants. Six genotypes Pl1Pl1Pl2Pl2, Pl1Pl1Pl2pl2, Pl1Pl1pl2pl2, Pl1pl1Pl2Pl2,Pl1pl1Pl2pl2, Pl1pl1pl2pl2 were resistant, 2 genotypes pl1pl1Pl2Pl2, pl1pl1Pl2pl2 were moderately resistant and one genotype pl1pl1pl2pl2 was susceptible. Since the cultivars harboring the Pl1 gene with homozygosity always produced resistant plants to the disease in any cross combinations, they could become very important materials for the breeding of cultivars resistant to the disease.

First Report of Leaf Blight on Sweet Persimmon Tree by Pestalotiopsis theae in Spain.

During July 1998, a leaf blight caused by Pestalotiopsis theae (Saw.) Stey. was observed at an incidence of 18 to 20% in sweet persimmon (Diospyros kaki L.fil.) orchards in Huelva Province (southwestern Spain). Symptoms appeared on leaves as large grayish brown circular ringspots. Usually, they were solitary, but occasionally, two to three spots occurred on an affected leaf. In severe cases, lesions developed on more than one-third of the leaf, resulting in defoliation. Small black acervular conidiomata were visible in the surface of spots. These conidiomata produced fusiform conidia that were straight or rarely curved, four five-celled euseptate, including three olivaceous or dark brown median cells, and hyaline apical and basal cells with appendages that were slightly constricted at septa. Conidiomata were up to 240 μm in diameter; conidiogenous cells were 6 to 13 × 1.2 to 2.8 μm; conidia were 24.7 × 7.8 μm; three median cells were 16.7 μm long; two to three apical appendages (rarely four) were 28.3 μm long; and straight basal appendage was 5.7 μm. P. theae was consistently isolated on potato dextrose agar from diseased leaves and conidiomata. To confirm pathogenicity, both mycelial plugs and a conidial suspension (1.5 × 106 conidia per ml) of the fungus were used as inocula. Young completely developed leaves from persimmon tree cvs. Sharon and Hanafuyu were inoculated in the laboratory and maintained in a moist chamber for 5 days. Lesions resembling symptoms that occurred in the field were observed on leaves after 5 days. Symptoms were not observed on control leaves inoculated with agar media or sprayed with water. The fungus reisolated from diseased leaves was identical to the original isolates. Based on the morphological characteristics of conidiomata and conidia as well as pathogenicity, the fungus was identified as P. theae (1). This is the first report of this fungus as a pathogen of D. kaki in Europe. Possibly the introduction of P. theae to Spain has been through young imported persimmon plants. Unusual climatic conditions (heavy rainfalls during 1997 in southwestern Spain) have been favorable for disease development. The hot and dry conditions that usually occur during flowering, growing, and maturation of persimmon fruits normally prevent dissemination of inoculum and infection of leaves. For these reasons, the wet areas of southwestern Spain could be more favorable for "grey blight" of persimmon trees. Reference: (1) T.-H. Chang et al. Korean J. Plant Pathol. 12:377, 1996.

Pesthetoxin, a New Phytotoxin Produced by the Gray Blight Fungus, Pestalotiopsis theae.

Pestalotiopsis theae is known to be a causal fungus for tea gray blight disease. Pesthetoxin was isolated from P. theae as a potent leaf-necrosis substance against tea. The structure of pesthetoxin was established principally by NMR studies to be of four different enolic forms, viz the pairs of internal tautomers (1a)/(1b) and (1c)/(1d) with external tautomerism between them.

SYNTHESIS AND PROPERTIES OF NOVEL α-PHOSPHORYL(THIO)UREIDOALKANEPHOSPHONATE DERIVATIVES

Abstract Two series of novel α-phosphoryl(thio)ureido alkanephosphonate derivatives (5,6) have been synthesized by a convenient, multistep route involving the addition reaction of phosphoryl isothiocyanides with α-aminoalkanephosphonates and a homogeneous desulphurisation utilizing Ag+-H2O system as key steps. The carbodiimide intermediate 8 in the conversion of compounds 5 into 6 was trapped to afford regioselectively the corresponding imino-ether 9 instead of its isomer 10. All the compounds prepared were confirmed by 1H NMR, IR, MS, 31P NMR and elemental analysis. Preliminary bioassays indicate that compounds 5 and 6 have potent antiphytoviral activities against the tobacco mosaic virus (TMV). In addition, some of 5 possess selective herbicidal activities and some of 5 and 6 exhibit good fungicidal activities against wheat leaf rust and cucumber grey blight.

Evaluation of antiserum raised againstPestalotiopsis theœ for the detection of grey blight of tea by ELISA

Polyclonal antiserum was raised against the mycelial extract ofPestalotiopsis theœ and immunoglobulin fractions were purified by ammonium sulfate fractionation and chromatography on DEAE-Sephadex. In enzyme-linked immunosorbent assay, antiserum dilution up to 1∶16000 detected homologous antigen at a 5 mg/L concentration, and at 1∶125 antiserum dilution fungal antigens could be detected at a concentration as low as 25 μg/L. In fifteen varieties of tea tested, originating from Darjeeling, UPASI and Tocklai breeding stations, absorbance values of infected leaf extracts were significantly higher than those of healthy extracts at a concentration of 40 mg/L in indirect ELISA. ELISA-positive material was detected in tea leaves as early as 12 h after inoculation withP. theœ. At antiserum dilutions up to 1∶125, the pathogen could be detected in inoculated leaf extracts up to antigen concentration of 2 mg/L. The antiserum reacted with two other isolates ofP. theœ tested but not with the antigens from mycelial extracts ofGlomerella cingulata andCorticium invisum or with extracts of tea leaves inoculated with these pathogens. The results demonstrate that ELISA can be used for early detection ofP. theœ in leaf tissues even at a very low level of infection.

Varietal Differences of Resistance to Tea Gray Blight in the Genetic Resources of Tea (Camellia sinensis)

For the breeding of varieties resistant to tea gray blight caused by Pestalotiopsis longiseta (Spegazzini) Dai et Kobayashi, varietal differences of resistance to the fungus were investigated in 195 cultivars and genetic resources of tea. The resistance to the disease was classified into 5 grades from high resistance to hight susceptibility based on the rate of formation and the size of zonate spot lesions.In resistance to tea gray blight, most of the Japanese local varieties were resistant, but some cultivated varieties and breeding lives such as 'Sayamamidori, Yabukita, Toyoka, Hokumei, Asatsuyu, Natsumidori, Okumusashi' and 'Saemidori' for green tea were susceptible or slightly susceptible.The Japanese local varieties were almost susceptible, China type plants were the middle susceptible and Assam hybrids were slightly susceptible.

Detection of cross reactive antigens between Pestalotiopsis theae and tea leaves and their cellular location

SummaryAmong the 12 varieties of tea tested against three isolates of Pestalotiopsis theae, causal agent of grey blight disease, Teen Ali‐17/1/54 and TV‐23 were found to be highly susceptible while CP‐1 and TV‐26 were resistant under identical conditions. Leaf antigens were prepared from all the tea varieties, three isolates of P. theae and a non‐pathogen of tea (Bipolaris tetramera). Polyclonal antisera were raised against mycelial suspensions of P. theae (isolate Pt‐2) and leaf antigens of Teen Ali‐17/1/54 and CP‐1. These were compared an immunodiffusion test and enzyme‐linked immunosorbent assay to detect cross reactive antigens (CRA) shared the host and the parasite. CRA were found among the susceptible varieties and isolates of P. theae (Pt‐1, 2 and 3). Such antigens were not detected between isolates of P. theae and resistant varieties, B. tetramera and tea varieties or isolates of P. theae. Indirect staining of antibodies using fluorescein isothiocyanate (FITC) indicated that in cross sections of tea leaves, the CRA was concentrated in the epidermal cells and mesophyll tissues. CRA was present in the young hyphal tips of the mycelia and on the setulae and appendages of the conidia of P. theae.

チャ葉でのチャ輪斑病（Ｐｅｓｔａｌｏｔｉａ ｌｏｎｇｉｓｅｔａ）の発生に及ぼすチャ赤葉枯病菌（Ｇｌｏｍｅｒｅｌｌａ ｃｉｎｇｕｌａｔａ）の影響

チャ葉でのチャ輪斑病（Ｐｅｓｔａｌｏｔｉａ ｌｏｎｇｉｓｅｔａ）の発生に及ぼすチャ赤葉枯病菌（Ｇｌｏｍｅｒｅｌｌａ ｃｉｎｇｕｌａｔａ）の影響

チャの新梢枯死症の原因

The shoot blight of tea plant causing sever damage to tea production in Japan was etiologically investigated. This disease was found to be caused by the tea gray blight fungus, Pestalotia longiseta. The tea brown blight fungus, Glomerella cingulata, was often detected on the diseased shoots, but it was considered to be a secondary parasite.

Incidence of Strains of the Tea Gray Blight Fungi Pestalotia longiseta and P. theae Resistant to Benzimidazole Fungicides in Japan

To investigate the occurrence of strains of the tea gray blight fungus Pestalotia longiseta and P. theae resistant to benzimidazole fungisides (Topsin M, Benlate), tea leaves affected by the disease were collected from 14 major tea-producing prefectures in Japan. An isolate from each diseased leaf was examined on PDA media containing thiophanate-methyl (Topsin M) of the concentrations of 0, 1, 100 ppm. The medium inhibitory concentration (MIC) for several isolates and the geographical distribution of the tea gray blight fungi Pestalotia spp., i. e. P. longiseta, P. theae were also analyzed. In 68 tea fields out of the 119 tested resistant strains (1ppm inhibition) were detected, although highly-resistant ones (100ppm inhibition) were obtained from 54 fields. The ratio of detection of the resistant strains in Shizuoka, Mie, Saga, Miyazaki and Kagoshima Prefectures was high, whereas in Tokushima and Kochi Prefectures resistant strains were not detected. Regarding the geographical distribution of the Pestalotia spp., most of the P. longiseta species were isolated in Shizuoka, Aichi, Mie, Shiga, and Nara Prefectures. While in Saitama, Tokushima, and Kumamoto Prefectures, the P. theae species were isolated more frequently than the P. longiseta ones.

Influence of Spray Methods on Control of Tea Gray Blight Caused by Pestalotia longiseta SPEGAZZINI

By using a small-sized power sprayer (power spray:ARIMITU CS-10K) and a power sprayer drivel battery (battery sprayer:TOSHIBA GARDEN SPRAYER EH-15), the eftect of spray pressure on the contral of Gray blight was studied.Two fungicides, chlorothalonil (75% WP, dilu-tion:1/600) and captafol (80% WP, 1/2000) were sprayed 200 litres per 10 a. to tea bushes within a few hour after the artficially inoculation of Pestalotia longiseta SPEGAZZINI. The discharge rates of the power sprayer and the battery sprayer were 4.76l/min and 0.29 1/min, respectively.The spray pressures on an area of 5×5 cm at a distance of 30 cm from nozzle of a sprayer were 159g in the power sprayer and 2g in the battery sprayer.In the application of chlorothalonil, the number of diseased leaves was significantly fewer in the power sprayer than in the battery sprayer. On the case of captafol, the power sprayer also showed the effective control on Gray blight.

チャ輪はん病菌（Ｐｅｓｔａｌｏｔｉａ ｌｏｎｇｉｓｅｔａ）接種チャ枝における菌の交代

チャ輪はん病菌（Ｐｅｓｔａｌｏｔｉａ ｌｏｎｇｉｓｅｔａ）接種チャ枝における菌の交代

Effects of Spreaders on Fungicidal Actions Controlling Tea Gray Blight and on Residue of Fungicide in Tea leaf

P.longiseta SPEG. によるチャ輪斑病防除薬剤のうち,クロロタロニル剤,カプタホル剤,チオファネートメチル剤について,浸透性を付加させるとされている展着剤アトロックスBI,トクエース,ラビサンスプレーを加用した場合の効果について調査した。クロロタロニル剤800倍液は単用で散布した場合,摘採数時間後以内に処理しなければ効果がないとされていたが,アトロックスBIを500～1000倍で加用すると,摘採1日後においても若干の防除効果が認められた。しかし,摘採1日後の防除効果は実用的にはやや不十分であり,アトロックスBIを加用した場合でも,摘採当日中の散布が必要であると考えられた。トクエース(1000倍),ラビサンスプレー(500倍)も同等の効果が認められた。カプタホル剤は,摘採1日後散布では防除効果は実用的にやや不十分とされていたが,アトロックスBIを500～1000倍で加用したところ,摘採1日後散布においても十分な効果が認められた。摘採2日後以降の散布では効果不十分であった。トクエース(1000倍),ラビサンスプレー(500倍)も同等の効果が認められた。チオファネートメチル剤2000倍液にアトロックスBIを500倍で加用し,摘採5日後散布の防除効果を調査したが,効果は認められなかった。クロロタロニル剤800倍,アトロックスBI500倍の組み合わせについて,散布後12日目に製茶した荒茶について,ガスクロマトグラフィーを用い茶抽出液と荒茶の両者について残留性を調べたところ,残留量はアトロックスBIの加用により減少した。このことは加用による濡れ性の向上に伴ない,初期付着量が減少したためと考えられ,残留性について問題はなかった。

Effective Fungicides and Application Time for Control of Tea Gray Blight Caused by Pestalotia longiseta Speg

Effective Fungicides and Application Time for Control of Tea Gray Blight Caused by Pestalotia longiseta Speg

Mycological Notes on Two Species of Pestalotia Parasitic on Tea Plant

Two species of fungi belonging to the genus Pestalotia were found to be parasitic on leaves and young stems of tea variety Natsumidori showing the symptom of in Shizuoka Prefecture during 1954.One was undoubtedly identical in the morphological characters with Pestalotia theae SAW. which was hitherto considered to be responsible for of tea plant. The other was very much similar to Pestalotia palmarum CKE. described by SAWADA (1913, '15) to be weakly parasitic on tea plant in Taiwan.GUBA (1929, '32) emphasized the host specificity in Pestalotia fungi and stated that the species were closely restricted to one host or several hosts in related genera. According to him, the host range of P. palmatunl CKE. is restricted within the species of palms, and P. theae SAW. alone can be parasitic on tea plant.Despite of GUBA's assertion, it is true that there is another species of Pestalotia parasitic on tea plant in Japan and presumably in Taiwan. The authors' species is apparently different from P. theae SAW. in its shorter conidial size, in its usually colour of two upper coloured cells than the lower, and in its setae never This species is rather similar to P. palmaruyn CKE. on palms described carefully by GUBA, though it is slightly different from GUBA's description where the two upper coloured cells are occasionally darker than the lower and the setae are often knobbed. It is a difficult question whether these slight differences are valid for distinguishing one species from another. The answer depends on the validity of the host specificity in .Pestalotia proposed by GUBA. The conclusive identification of the authors' species is retained here because of the lack of reciprocal inoculation experiment between the species and P. palmarum CKE. from palms.The symptoms on tea due to both fungi of P. there SAw. and the unidentified species are just the same, so that it was impossible to distinguish them with the naked eye. It is proposed to apply the name grey blight to the disease including both fungi parasitic on tea plant, as a matter of practical convenience in agriculture.

Pestalotiopsis theae . [Descriptions of Fungi and Bacteria

Abstract A description is provided for Pestalotiopsis theae . Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Camellia sinensis ; also recorded on Cocos, Diospyros, Elaeis, Gossypium, Mangifera, Syzgium, Theobroma and a number of other unrelated hosts. DISEASE: Grey blight of tea, which begins as small brown spots on the leaves, later enlarging to 1 cm diam. or more and showing (on the upper surface) a greyish centre with light to dark brown margins. Lesions are usually circular or oval with concentric zonations marked out on the upper surface by the dark acervuli. On young leaves these zonations are often absent. Coalescence of the spots may occur. GEOGRAPHICAL DISTRIBUTION: Australia, Azores, Brazil, Burma, Ceylon, China, Canary Island, Ethiopia, Formosa, Ghana, Guinea, Hawaii, Hong Kong, India, Indonesia, Iran, Japan, Kenya, Laos, Malagasy Republic, Malawi, Malaysia, Mozambique, Nepal, Papua New Guinea, Peru, Rhodesia, Sierra Leone, Somaliland, S. Africa, Tanzania, Thailand, Turkey, Uganda, USSR, Vietnam (S.). TRANSMISSION: No detailed studies reported; the spores may be soil-borne (40: 184).