scholarly journals Response of Intermediate Ripening Tobacco (Nicotiana tabacum) Cultivars to Frog Eye (Cercospora nicotianae) and Alternaria Leaf Spot (Alternaria alternata) in the Medium Growing Areas of Zimbabwe

2021 ◽  
Author(s):  
Justify Gotami Shava
Keyword(s):  
Nicotiana Tabacum ◽  
Alternaria Alternata ◽  
Leaf Spot ◽  
Block Design ◽  
Tobacco Leaf ◽  
Foliar Diseases ◽  
Agronomic Practices ◽  
Alternaria Leaf Spot ◽  
Yield And Quality ◽  
Grade Index

Background: Alternaria leaf spot (Alternaria alternata) and Frog eye leaf spot (Cercospora nicotianae) are foliar diseases of tobacco (Nicotiana tabacum) which occur mainly in mature tobacco. Hence, the diseases are often associated with maturity of cured tobacco leaf at the tobacco sales floor in Zimbabwe. Where they occur, they can result in significant reductions in yield and quality of cured tobacco leaf. Methods: A study was carried out in Trewaney, Mashonaland West province in Zimbabwe to investigate the response of newly developed ten flue cured tobacco varieties to the two foliar diseases Alternaria leaf spot (Alternaria alternata) and frog eye leaf spot (Cercospora nicotianae). The experiment was laid out as a randomized complete block design (RCBD) with three replicates. Standard agronomic practices in tobacco farming were followed and disease assessments were done 18 weeks after planting. Result: Significant differences (p less than 0.05) for resistance to alternaria leaf spot were observed with the experimental hybrid T60 showing the highest resistance to the disease with a disease score of 1.6 under a 0-6 disease scale that ranges from 0 (no disease) to 6 (severely affected). However, there were no significant (p greater than 0.05) differences among the varieties for frog eye leaf spot resistance, yield (kg/ha) and quality as measured by the grade index, however, K 326 showed the highest resistance to frog eye leaf spot. All the varieties, however, showed resistance to the two diseases. It was concluded that K 326 was the source of the resistance to frog eye leaf spot in all the experimental hybrids evaluated and that T60 had the highest Alternaria leaf spot resistance obtained from its parents which are both classified as resistant to the disease.

scholarly journals First Report of Alternaria Leaf Spot of Banana Caused by Alternaria alternata in the United States

Plant Disease ◽  
2013 ◽  
Vol 97 (8) ◽  
pp. 1116-1116 ◽  
Author(s):  
V. Parkunan ◽  
S. Li ◽  
E. G. Fonsah ◽  
P. Ji
Keyword(s):  
United States ◽  
Alternaria Alternata ◽  
Leaf Spot ◽  
Morphological Characteristics ◽  
The United States ◽  
Its Sequencing ◽  
Single Spore ◽  
First Report ◽  
Alternaria Leaf Spot ◽  
Leaf Spots

Research efforts were initiated in 2003 to identify and introduce banana (Musa spp.) cultivars suitable for production in Georgia (1). Selected cultivars have been evaluated since 2009 in Tifton Banana Garden, Tifton, GA, comprising of cold hardy, short cycle, and ornamental types. In spring and summer of 2012, 7 out of 13 cultivars (African Red, Blue Torres Island, Cacambou, Chinese Cavendish, Novaria, Raja Puri, and Veinte Cohol) showed tiny, oval (0.5 to 1.0 mm long and 0.3 to 0.9 mm wide), light to dark brown spots on the adaxial surface of the leaves. Spots were more concentrated along the midrib than the rest of the leaf and occurred on all except the newly emerged leaves. Leaf spots did not expand much in size, but the numbers approximately doubled during the season. Disease incidences on the seven cultivars ranged from 10 to 63% (10% on Blue Torres Island and 63% on Novaria), with an average of 35% when a total of 52 plants were evaluated. Six cultivars including Belle, Ice Cream, Dwarf Namwah, Kandarian, Praying Hands, and Saba did not show any spots. Tissue from infected leaves of the seven cultivars were surface sterilized with 0.5% NaOCl, plated onto potato dextrose agar (PDA) media and incubated at 25°C in the dark for 5 days. The plates were then incubated at room temperature (23 ± 2°C) under a 12-hour photoperiod for 3 days. Grayish black colonies developed from all the samples, which were further identified as Alternaria spp. based on the dark, brown, obclavate to obpyriform catenulate conidia with longitudinal and transverse septa tapering to a prominent beak attached in chains on a simple and short conidiophore (2). Conidia were 23 to 73 μm long and 15 to 35 μm wide, with a beak length of 5 to 10 μm, and had 3 to 6 transverse and 0 to 5 longitudinal septa. Single spore cultures of four isolates from four different cultivars were obtained and genomic DNA was extracted and the internal transcribed spacer (ITS1-5.8S-ITS2) regions of rDNA (562 bp) were amplified and sequenced with primers ITS1 and ITS4. MegaBLAST analysis of the four sequences showed that they were 100% identical to two Alternaria alternata isolates (GQ916545 and GQ169766). ITS sequence of a representative isolate VCT1FT1 from cv. Veinte Cohol was submitted to GenBank (JX985742). Pathogenicity assay was conducted using 1-month-old banana plants (cv. Veinte Cohol) grown in pots under greenhouse conditions (25 to 27°C). Three plants were spray inoculated with the isolate VCT1FT1 (100 ml suspension per plant containing 105 spores per ml) and incubated under 100% humidity for 2 days and then kept in the greenhouse. Three plants sprayed with water were used as a control. Leaf spots identical to those observed in the field were developed in a week on the inoculated plants but not on the non-inoculated control. The fungus was reisolated from the inoculated plants and the identity was confirmed by morphological characteristics and ITS sequencing. To our knowledge, this is the first report of Alternaria leaf spot caused by A. alternata on banana in the United States. Occurrence of the disease on some banana cultivars in Georgia provides useful information to potential producers, and the cultivars that were observed to be resistant to the disease may be more suitable for production. References: (1) E. G. Fonsah et al. J. Food Distrib. Res. 37:2, 2006. (2) E. G. Simmons. Alternaria: An identification manual. CBS Fungal Biodiversity Center, Utrecht, Netherlands, 2007.

scholarly journals Alternaria leaf spot of broccoli caused by Alternaria alternata in Bangladesh

2021 ◽  
Author(s):  
Sayma T. Nira ◽  
Md. Farhad Hossain ◽  
Nur Uddin Mahmud ◽  
Oliul Hassan ◽  
Md. Tofazzal Islam ◽  
...  
Keyword(s):  
Alternaria Alternata ◽  
Leaf Spot ◽  
Maximum Growth ◽  
Pathogenicity Test ◽  
Culture Studies ◽  
Alternaria Leaf Spot ◽  
Cultural Methods ◽  
Molecular Phylogenetic ◽  
Alternaria Sp

  This study aimed to isolate and characterise the pathogen associated with Alternaria leaf spot on broccoli and to evaluate the inhibitory effects of fungicides against it. We isolated and identified the fungal pathogen as Alternaria sp. using morphological and cultural methods. Based on the aligned sequences of the internal transcribed spacer (ITS) and molecular phylogenetic analysis by the neighbour-joining method, the isolates (Ab1 and Ab2) were confirmed as Alternaria alternata. The conidia of the isolates were dark brown, cylindrical, obclavate to muriform. The conidiophores were olivaceous brown, septate, and branched. The conidial morphology of the isolates ranged from 52.4–92.4 × 10–20 μm with 2–6 transverse and 0–3 longitudinal septa. Both isolates yielded positive results in the pathogenicity test on broccoli leaves by developing brown and circular spots with concentric rings on the leaves surrounded by yellow halos. The culture studies revealed that the maximum growth of the pathogen was obtained at 30 °C and pH 6.0. Tilt 250 WC showed the highest potential in suppressing the mycelial growth of the A. alternata in vitro at a concentration as low as 50 µg/mL. The results from this study contributed to the positive identification of the pathogen and characterised A. alternata as a destructive pathogen of broccoli which may be successfully controlled by the fungicide Tilt.  

PENGARUH POPULASI TANAMAN TERHADAP SIFAT AGRONOMIS SERTA KADAR Cl DAUN TEMBAKAU VIRGINIA RAJANGAN PADA TANAH VERTISOLS DI BOJONEGORO

2020 ◽  
Vol 9 (4) ◽  
pp. 129
Author(s):  
ABDUL RACHMAN ◽  
NFN MAHFUDZ
Keyword(s):  
Nicotiana Tabacum ◽  
Tobacco Plant ◽  
Block Design ◽  
Plant Population ◽  
Tobacco Leaves ◽  
Randomized Block Design ◽  
Leaf Yield ◽  
Curing Method ◽  
Agronomic Characteristic ◽  
Grade Index

<p>Percobaan lapang telah dilakukan pada tanah vetisol di Kebun Percobaan Pekuwon, Bojonegoro, dimulai Mei sampai September 1996, untuk mempelajari pengaruh populasi tanaman tembakau terhadap sifat agronomis dan kadar Cl daun tanaman tembakau Virginia yang diolah dengan cara dirajang. Tinggi tempat dari lahan percobaan 13 m dpi, dan dengan tipe iklim D. Tanah bertekstur liat dengan 80% liat, 15% debu dan 5% pasir, 0.62% C-organik, 0.10% N, dan pH 8.20. Percobaan disusun dalam ancangan acak kelompok dengan 4 ulangan. Perlakuan terdiri dari enam laraf populasi tanaman tembakau (12 000; 18 000; 24 000; 36 000; 48 000, dan 60 000 tanaman per ha atau setara dengan 144, 216, 288, 432, 576, dan 720 tanaman per petak). Ukuran petak 12 m x 10 m. Dalam percobaan ini akan dipelajari pula pengaruh bentuk hasil (rajangan dan krosok) terhadap kadar Cl daun. Sepuluh tanaman per petak diolah secara lue-cuing di dalam oven mini, untuk dianalisis kadar Cl daunnya. Varietas tembakau adalah DB 101. Hasil dan indeks tanaman masih terus meningkat sampai populasi tetinggi, sedangkan mutu dan rendemen tidak terpengaruh oleh peningkatan populasi. Peningkatan populasi sebaliknya menurunkan ukuran daun, bobot tiap daun, tinggi tanaman, lingkar batang, dan jumlah daun yang dapat dipanen. Berdasar hasil, mutu dan mudahnya pengelolaan di lapang populasi yang optimal adalah 24 000 tanaman per ha, untuk tembakau Virginia rajangan di Bojonegoro. Peningkatan populasi hanya berpengaruh pada kadar Cl daun atas saja. Sedangkan bentuk hasil tembakau ajangan dan krosok tidak berpengaruh pada kadar Cl daun.</p><p>Kata kunci: Nicotiana tabacum, tembakau. tembakau Virginia rajangan, populasi tanaman, vertisols, sifat agronomis, kadar Cl, bentuk olahan</p><p> </p><p><strong>ABSTRACT </strong></p><p><strong>Effect of plant population on agronomic characteristics and leaf Cl content of sliced Virginia tobacco grown in vertisols of Bojonegoro</strong></p><p>The expeiment was conducted in vetisol soil of Bojonegoro in 1996 to study the effect of plant population on agronomic characteistics and Cl content of sliced tobacco leaves. The experiment was site located 13 m above sea level, with D climatic type. The soil characteristics were clay texture with 80% clay, 15% silt and 5% sand, 0.62% C-organic, 0.10 % N, and pH 8.2. The treatment consisted of six plant populations (12.000 up to 60.000 plants per ha equal with 144, 216, 288, 432, 576, and 720 plants per plot) was arranged in a randomized block design, with four replications. Plot size was 12 m x 10 m. Plant population per plo( based on the six treatment levels. For Cl content analysis, 10 plants plot was also taken to be processed with lue-curing method in mini oven. Tobacco variety was DB 101. Yield and crop index increased steadily as plant population increased up to the highest plant population. However the increase in plant population decreased the size, weight, number of leaves, and plant height. While grade index, percentage of dry to fresh leaf yield and Cl content of lower and middle leaves were not affected by the increase in plant population. Base on yield, quality, and easier management, the recommended plant population was 24 000 plant per ha. The increase in plant population only affected the Cl content of upper leaves. The form of sliced and lue-cured tobacco leaves did not affect the Cl content of (he leaves.</p><p>Key words : Nicotiana tabacum, tobacco, sliced Virginia tobacco, plant population vetisols, agronomic characteristic, Cl contcnl, product form</p>

First report of Alternaria leaf spot caused by Alternaria alternata (Fries.) Kiessler on Sonchus oleraceus L. and Convolvulus arvensis L. in Algeria

2019 ◽  
Vol 167 (6) ◽  
pp. 321-325
Author(s):  
Nesma Abdessemed ◽  
Ali Kerroum ◽  
Youssef Anis Bahet ◽  
Nacèra Talbi ◽  
Nadjia Zermane
Keyword(s):  
Alternaria Alternata ◽  
Leaf Spot ◽  
Convolvulus Arvensis ◽  
First Report ◽  
Sonchus Oleraceus ◽  
Alternaria Leaf Spot

Alternaria leaf spot of basil caused by Alternaria alternata in Japan

2009 ◽  
Vol 75 (2) ◽  
pp. 160-162 ◽  
Author(s):  
Satoshi Taba ◽  
Ayano Takara ◽  
Kanami Nasu ◽  
Nao Miyahira ◽  
Tetsuya Takushi ◽  
...  
Keyword(s):  
Alternaria Alternata ◽  
Leaf Spot ◽  
Alternaria Leaf Spot

scholarly journals PENGARUH PENYAKIT KRUPUK TERHADAP HASIL DAN MUTU DELAPAN VARIETAS TEMBAKAU VIRGINIA

2020 ◽  
Vol 6 (2) ◽  
pp. 33
Author(s):  
GEMBONG DALMADIYO ◽  
MOCH. AMIR KARTAMIDJAJA
Keyword(s):  
Block Design ◽  
Susceptible Variety ◽  
Diseased Plant ◽  
Yield And Quality ◽  
Randomized Block Design ◽  
Resistant Varieties ◽  
Tobacco Seedlings ◽  
Grade Index ◽  
Leaf Curl Disease

<p><strong>The effect of tobacco curl disease on the yield and quality of eight Virginia tobacco varieties</strong></p><p>Tobacco leaf curl disease is one of the important diseases on Virginia tobacco which especially occurs in dry condition. The use of resistant varieties is one of the most effective way to control the disease. This experiment was lo evaluate the effect of tobacco curl disease on tobacco varieties (DB 101, Coker 319, Coker 176, Coker 48, Coker 86, and Coker 371 Gold) and two promising lines (T.45/T.65 and T.45/T.69). The experiment was conducted in Pekuwon, Sumberrejo, Bojonegoro from April to October 1997. The experiment was arranged in randomized block design with three replications. The tobacco seedlings wee transplanted in 0.9 m x 0.6 m spacing and 9.0 m x 9.0 m plot size. The fertilizer dosage applied are 300 kg ZA + 108 kg SP-36 + 156 kg ZK per ha The parameters observed including percentage of diseased plant, productive leaves, as well as the yield and quality of leaves. The esults showed that Coker 371 Gold variety showed the lowest disease percentage (6.89%), decrease in productive leaves was high (71.86%), Whereas the two promising lines, were T.45/T.6S and T.45/T.69 showed that the percentage of diseased plants wee not significantly different compared with DB 101, Coker 319, and Coker 48, but the decrease in productive leaves was lower. The yield of these promising lines were 10.12-10.30 kg/81 m!, grade indexes 86.04-87.27, and crop indexes are 88.31-88.63. Coker 176 was the most susceptible variety. The percentage of diseased plant, flue- cured yield, grade index, and crop index on Coker 176 wee 42.67%, 7.77 kg/81 m!, 86.09, and 66.89, respectively.</p>

scholarly journals First Report of Alternaria Leaf Spot Caused by Alternaria alternata on Spinach in Poland

Plant Disease ◽  
2015 ◽  
Vol 99 (5) ◽  
pp. 729-729 ◽  
Author(s):  
A. Czajka ◽  
A. Czubatka ◽  
J. Sobolewski ◽  
J. Robak
Keyword(s):  
Alternaria Alternata ◽  
Leaf Spot ◽  
First Report ◽  
Alternaria Leaf Spot
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