Apical chlorosis and leaf spot of Tagetes spp. caused by Pseudomonas tagetis Hellmers

1978 ◽  
Vol 29 (4) ◽  
pp. 831 ◽  
Author(s):  
D Trimboli ◽  
PC Fahy ◽  
KF Baker
Keyword(s):  
Leaf Spot ◽  
Zinnia Elegans ◽  
Tagetes Erecta ◽  
Diverse Range ◽  
Biochemical Characteristics ◽  
Leaf Spots ◽  
Spray Inoculation

An undescribed apical chlorosis caused severe losses in seedlings of Tagetes erecta and T. patula types in Sydney, Brisbane and Melbourne in 1976. Bacterial leaf spots without chlorotic haloes invariably accompanied the disease. The same bacterium was isolated from leaf lesions and chlorotic tissue and produced leaf spots and chlorosis on marigold, zinnia and sunflower with spray inoculation. Leaf spots did not develop on T. signata. Apical chlorosis developed on a diverse range of plants following wound inoculation. The pathogen was shown to be seed-borne. The pathogen was identified as Pseudomonas tagetis, cultural and biochemical characteristics described, and a neotype culture proposed. An exotoxin was produced in vitro which caused apical chlorosis in Zinnia elegans and T. patula.

Corrigendum - Apical chlorosis and leaf spot of Tagetes spp. caused by Pseudomonas tagetis Hellmers

1978 ◽  
Vol 29 (4) ◽  
pp. 831
Author(s):  
D Trimboli ◽  
PC Fahy ◽  
KF Baker
Keyword(s):  
Leaf Spot ◽  
Zinnia Elegans ◽  
Tagetes Erecta ◽  
Diverse Range ◽  
Biochemical Characteristics ◽  
Leaf Spots ◽  
Spray Inoculation

An undescribed apical chlorosis caused severe losses in seedlings of Tagetes erecta and T. patula types in Sydney, Brisbane and Melbourne in 1976. Bacterial leaf spots without chlorotic haloes invariably accompanied the disease. The same bacterium was isolated from leaf lesions and chlorotic tissue and produced leaf spots and chlorosis on marigold, zinnia and sunflower with spray inoculation. Leaf spots did not develop on T. signata. Apical chlorosis developed on a diverse range of plants following wound inoculation. The pathogen was shown to be seed-borne. The pathogen was identified as Pseudomonas tagetis, cultural and biochemical characteristics described, and a neotype culture proposed. An exotoxin was produced in vitro which caused apical chlorosis in Zinnia elegans and T. patula.

scholarly journals First Report of Leaf Spot Caused by Alternaria alternata on Marigold (Tagetes erecta) in Beijing, China

Plant Disease ◽  
2014 ◽  
Vol 98 (8) ◽  
pp. 1153-1153 ◽  
Author(s):  
Y. Li ◽  
J. Shen ◽  
B. H. Pan ◽  
M. X. Guo ◽  
Q. X. Wang ◽  
...  
Keyword(s):  
Alternaria Alternata ◽  
Leaf Spot ◽  
Leaf Spot Disease ◽  
Tagetes Erecta ◽  
Pathogenicity Test ◽  
First Report ◽  
Leaf Spots ◽  
Commercial Crop ◽  
Necrotic Spots ◽  
Beijing China

Marigold (Tagetes erecta) is an important commercial crop and 200 ha are planted every year in the Beijing district of China. A leaf spot disease of T. erecta was observed during 2012 and 2013 in the Beijing district. The disease was widespread, with 60 to 75% of the fields affected. Leaves of the affected plants had small, brown, necrotic spots on most of the foliage. Yield losses of flowers of up to 20 to 30% were reported. The spots gradually enlarged, becoming irregular in shape, or remained circular, and with concentric rings or zones. In the later stages of infection, the spots coalesced, and the leaves withered, dried, and fell from the plants (4). A fungus was consistently isolated on potato dextrose agar (PDA) from the infected leaves of T. erecta. After 6 days of incubation at 26°C and a 12-h photoperiod, the fungus produced colonies that were flat, with a rough upper surface (2). The conidiophores were short. Conidia varied from 18 × 6 to 47 × 15 μm and were medium to dark brown or olive-brown in color, short beaked, borne in long chains, oval and bean shaped, with 1 to 5 transverse septa and 0 to 2 longitudinal septa. The rDNA of the internal transcribed spacer regions 1 and 2 and the 5.8S gene in seven isolates were amplified using primers ITS1 (5′-TCCGTAGGTGAACCTGCGG-3′) and ITS4 (5′-TCCTCCGCTTATTGATATGC-3′). The nucleotide sequence was the same as isolate No. 7, which was deposited in GenBank (Accession No. KF307207). A BLAST search showed 97% identity with the strain Alternaria alternata GNU-F10 (KC752593). Seven isolates were also confirmed as A. alternata by PCR identification performed by specific primers (C_for/C_rev) of A. alternata (1). Seven isolates were grown on PDA for 2 weeks and the conidia harvested. A 5-μl drop of spore suspension (1 × 105 spores/ml) was placed on each leaflet of 140 detached, surface-sterilized T. erecta leaves. Twenty leaves were inoculated with sterile distilled water as a control. The leaves were incubated in a growth chamber at 80 to 90% relative humidity, 50 to 60 klx/m2 light intensity, and a 12-h photoperiod. After 6 days, leaf spots similar to the original developed at inoculation sites for all isolates and A. alternata was consistently re-isolated. The control leaves remained symptomless. The pathogenicity test was performed three times. Leaf spot of T. erecta caused by Alternaria spp. is well known in Asian countries such as Japan (3). To our knowledge, this is the first report of A. alternata on T. erecta in the Beijing district of China. References: (1) T. Gat. Plant Dis. 96:1513, 2012. (2) E. Mirkova. J. Phytopathol. 151:323, 2003. (3) K. Tomioka. J. Gen. Plant Pathol. 66:294, 2000. (4) T. Y. Zhang. Page 284 in: Flora Fungorum Sinicorum, Volume 16: Alternaria. Science Press, Beijing, 2003.

scholarly journals Pestalotiopsis desseminata PADA JAMBU MENTE BIOLOGI DAN INTERAKSINYA DENGAN Helopeltis antonii

2020 ◽  
Vol 6 (3) ◽  
pp. 66
Author(s):  
ESTHER M. ADHI ◽  
SUPRIADI SUPRIADI ◽  
S. RAHAYUNINGSIH ◽  
D. KILIN ◽  
NURI KARYANI
Keyword(s):  
Leaf Spot ◽  
Mycelial Growth ◽  
Agar Medium ◽  
Fungal Growth ◽  
Pathogenicity Test ◽  
Leaf Spots ◽  
Fungal Biology ◽  
Mycelia Growth ◽  
Medicinal Crops

<p><strong>Pestalotiopsis desseminata on cashew: its biology and interaction with Helopeltis antonii</strong></p><p>Pestalotiopsis desseminata is one of pathogens causing leaf spots. die-back of shoots and inflorescence of cashew plant. It is assumed there is an interaction between the attack of Helopeltis antonii and the fungus in Ihe ield so that the damage becomes more devastating. The objectives of (his research were to investigate several aspects of fungal biology (pathogenicity, mycelial growth, acervuli production, sensitivity to fungicides) and its interaction with //. antonii. The esearch was carried out from April 1999 to March 2000 at the laboratory and green house of Pest and Disease Department Research Institute for Spice and Medicinal Crops, Bogor. /' desseminata was diectly isolated from cashew leaves. Pathogenicity test of P. desseminata isolate was conducted on cashew seedlings. The fungal growth and fungicide effects were carried out in vitro on agar medium. The interaction between P. desseminata and H. antonii was examined by inoculating the fungus and insect, either individually or in combination, on cashew seedlings. The results showed that P. desseminata isolate fomis black spherical acervuli containing oblongs conidia with 5 cells, and the outermost cell has 3 flagellate. Acervuli could only be produced on the cultue illuminated continuously by 600 lux translucent lamp. Pathogenicity test of several isolates of /' desseminata on cashew seedlings caused spherical leaf spot symptom, individually or coalesced as bigger leaf spots. In vitro fungal mycelia growth could be suppressed by several fungicides, including bcnomyl 50% (I ppm) and Uiiopanate-mcthyl 70% (10 ppm) Combining inoculation between P. desseminata and //. antonii resulted in moe severe (devastating) die-back compared with individually inoculated.</p>

scholarly journals Mangrove Dieback and Leaf Disease in Sonneratia apetala and Sonneratia caseolaris in Vietnam

Forests ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1273 ◽  
Author(s):  
Huong Thi Thuy Nguyen ◽  
Giles E. St. J. Hardy ◽  
Tuat Van Le ◽  
Huy Quoc Nguyen ◽  
Duc Hoang Le ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Fungal Pathogens ◽  
Survival Rates ◽  
Tree Decline ◽  
Mangrove Restoration ◽  
Sonneratia Caseolaris ◽  
Leaf Spots ◽  
Black Leaf Spot ◽  
Stem Lesions

Even though survival rates for mangrove restoration in Vietnam have often been low, there is no information on fungal pathogens associated with mangrove decline in Vietnam. Therefore, this research was undertaken to assess the overall health of mangrove afforestation in Thanh Hoa Province and fungal pathogens associated with tree decline. From a survey of 4800 Sonneratia trees, the incidence of disorders was in the order of pink leaf spot > shoot dieback > black leaf spot for S. caseolaris and black leaf spot > shoot dieback > pink leaf spot for S. apetala. Approximately 12% of S. caseolaris trees had both pink leaf spot and shoot dieback, while only 2% of S. apetala trees had black leaf spot and shoot dieback. Stem and leaf samples were taken from symptomatic trees and fungi were cultured in vitro. From ITS4 and ITS5 analysis, four main fungal genera causing leaf spots and shoot dieback on the two Sonneratia species were identified. The most frequently isolated fungal taxa were Curvularia aff. tsudae (from black leaf spot),Neopestalotiopsis sp.1 (from stem dieback), Pestalotiopsis sp.1 (from pink leaf spot), and Pestalotiopsis sp.4a (from black leaf spot). The pathogenicity of the four isolates was assessed by under-bark inoculation of S. apetala and S. caseolaris seedlings in a nursery in Thai Binh Province. All isolates caused stem lesions, and Neopestalotiopsis sp.1 was the most pathogenic. Thus, investigation of fungal pathogens and their impact on mangrove health should be extended to other afforestation projects in the region, and options for disease management need to be developed for mangrove nurseries.

scholarly journals Molecular Phylogenetic Diversity and Biological Characterization of Diaporthe Species Associated with Leaf Spots of Camellia sinensis in Taiwan

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1434
Author(s):  
Hiran A. Ariyawansa ◽  
Ichen Tsai ◽  
Jian-Yuan Wang ◽  
Patchareeya Withee ◽  
Medsaii Tanjira ◽  
...  
Keyword(s):  
Camellia Sinensis ◽  
Leaf Spot ◽  
Phylogenetic Trees ◽  
Fungal Infections ◽  
Elongation Factor ◽  
Fungal Species ◽  
Tea Leaves ◽  
Phenotypic Characters ◽  
Leaf Spots ◽  
Molecular Phylogenetic

Camellia sinensis is one of the major crops grown in Taiwan and has been widely cultivated around the island. Tea leaves are prone to various fungal infections, and leaf spot is considered one of the major diseases in Taiwan tea fields. As part of a survey on fungal species causing leaf spots on tea leaves in Taiwan, 19 fungal strains morphologically similar to the genus Diaporthe were collected. ITS (internal transcribed spacer), tef1-α (translation elongation factor 1-α), tub2 (beta-tubulin), and cal (calmodulin) gene regions were used to construct phylogenetic trees and determine the evolutionary relationships among the collected strains. In total, six Diaporthe species, including one new species, Diaporthe hsinchuensis, were identified as linked with leaf spot of C. sinensis in Taiwan based on both phenotypic characters and phylogeny. These species were further characterized in terms of their pathogenicity, temperature, and pH requirements under laboratory conditions. Diaporthe tulliensis, D. passiflorae, and D. perseae were isolated from C. sinensis for the first time. Furthermore, pathogenicity tests revealed that, with wound inoculation, only D. hongkongensis was pathogenic on tea leaves. This investigation delivers the first assessment of Diaporthe taxa related to leaf spots on tea in Taiwan.

scholarly journals Photosynthesis of Blueberry Leaves as Affected by Septoria Leaf Spot and Abiotic Leaf Damage

Plant Disease ◽  
2004 ◽  
Vol 88 (4) ◽  
pp. 397-401 ◽  
Author(s):  
I. Roloff ◽  
H. Scherm ◽  
M. W. van Iersel
Keyword(s):  
Leaf Area ◽  
Disease Severity ◽  
Leaf Spot ◽  
Abiotic Factors ◽  
Lesion Size ◽  
Leaf Conductance ◽  
Yield Potential ◽  
Leaf Spots ◽  
Virtual Lesion ◽  
Septoria Leaf Spot

Leaf spots caused by fungal pathogens or abiotic factors can be prevalent on southern blueberries after harvest during the summer and fall, yet little is known about how they affect physiological processes that determine yield potential for the following year. In this study, we measured CO2 assimilation and leaf conductance on field-grown blueberry plants affected by Septoria leaf spot (caused by Septoria albopunctata) or by edema-like abiotic leaf blotching. Net assimilation rate (NAR) on healthy leaves varied between 6.9 and 12.4 μmol m-2 s-1 across cultivars and measurement dates. Infection by S. albopunctata had a significant negative effect on photosynthesis, with NAR decreasing exponentially as disease severity increased (R2 ≥0.726, P < 0.0001). NAR was reduced by approximately one-half at 20% disease severity, and values approached zero for leaves with >50% necrotic leaf area. There was a positive, linear correlation between NAR and leaf conductance (R2 ≥ 0.622, P < 0.0001), suggesting that the disease may have reduced photosynthesis via decreased CO2 diffusion into affected leaves. Estimates of virtual lesion size associated with infection by S. albopunctata ranged from 2.8 to 3.1, indicating that the leaf area in which photosynthesis was impaired was about three times as large as the area covered by necrosis. For leaves afflicted by edema-like damage, there also was a significant negative relationship between NAR and affected leaf area, but the scatter about the regression was more pronounced than in the NAR-disease severity relationships for S. albopunctata (R2 = 0.548, P < 0.0001). No significant correlation was observed between leaf conductance and affected area on these leaves (P = 0.145), and the virtual lesion size associated with abiotic damage was significantly smaller than that caused by S. albopunctata. Adequate carbohydrate supply during the fall is critical for optimal flower bud set in blueberry; therefore, these results document the potential for marked yield losses due to biotic and abiotic leaf spots.

Cochliobolus pallescens. [Descriptions of Fungi and Bacteria].

1990 ◽  
Author(s):  
A. Sivanesan
Keyword(s):  
Hong Kong ◽  
Sierra Leone ◽  
Papua New Guinea ◽  
Geographical Distribution ◽  
Leaf Spot ◽  
Solomon Islands ◽  
Ear Rot ◽  
Black Point ◽  
Leaf Spots ◽  
Windward Islands

Abstract A description is provided for Cochliobolus pallescens. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Common on many graminicolous and non-graminicolous hosts. Important cereals and grasses include Eleusine, Hordeum, Oryza, Panicum, Paspalum, Pennisetum, Poa, Saccharum, Setaria, Sorghum, Triticum and Zea economically important dicot hosts include Allium (59, 4867), Arachis (53, 1647), Brassica (66, 3075), Canna, Calendula, Calotropis (44, 1832; 66, 3587), Carica (61, 5129), Cinnamomum, Citrus (68, 843), Coriandrum, Dahlia, Fagopyrum (64, 2425), Gaillardia, Hevea (56, 1257; 67, 5560), Musa (54, 4051), Solanum (50, 3484). DISEASE: Leaf spots of cereals, black point of wheat (44, 102), leaf spot and on stems of rubber (56, 1257; 67, 5560), ear rot of barley (62, 1005), rot of garlic (59, 4867). GEOGRAPHICAL DISTRIBUTION: Australia, Bangladesh, Brunei, Burma, Canada, Colombia, Cuba, Denmark, Egypt, Ethiopia, Fiji, Ghana, Guinea, Hong Kong, India, Indonesia, Iran, Jamaica, Japan, Kenya, Malaysia, Malawi, Nepal, Nigeria, Pakistan, Papua New Guinea, Peru, Philippines, Sierra Leone, Singapore, Solomon Islands, Somalia, Sri Lanka, Swaziland, Sudan, Taiwan, Tanzania, Thailand, Trinidad, USA, USSR, Venezuela, Windward Islands, Zambia, Zimbabwe. TRANSMISSION: By wind-borne conidia and seed-borne.

Pestalotiopsis mangiferae. [Descriptions of Fungi and Bacteria].

1980 ◽  
Author(s):  
J. E. M. Mordue
Keyword(s):  
Hong Kong ◽  
Dominican Republic ◽  
Sierra Leone ◽  
Geographical Distribution ◽  
Leaf Spot ◽  
Host Plants ◽  
Solomon Islands ◽  
Mangifera Indica ◽  
Brown Spot ◽  
Leaf Spots

Abstract A description is provided for Pestalotiopsis mangiferae. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Mangifera indica; also on Anacardium occidentale, Combretum decandrum, Eucalyptus spp., Mimusops spp., Vitis vinifera and many other unrelated host plants. DISEASE: Grey leaf spot of Mangifera indica. The spots vary in size from a few mm to several cm in length, are usually sharply delimited by a dark, raised border, and are silvery grey above and grey to brown below; leaf spots on other hosts are similar. Brown spot or rot of mango fruits is also known. GEOGRAPHICAL DISTRIBUTION: Ghana, Nigeria, Sierra Leone, Tanzania, Uganda, Zaire, Zambia; Bangladesh, Brunei, Burma, Hong Kong, India, Malaysia, Nepal, Sabah, Solomon Islands, Sri Lanka; Australia; Dominican Republic; Venezuela. TRANSMISSION: Inoculation studies with conidia and mycelium have shown P. mangiferae to be a weak parasite, capable of infecting young injured leaves, injured fruits, older uninjured leaves and healthy fruits if in contact with diseased tissue (35, 378; 40, 421). It has been isolated from soil, but the possibility of transmission through soil has not been investigated.

scholarly journals Effects of botanicals against anthracnose and blight diseases of Houttuynia cordata Thunb

2016 ◽  
Vol 42 (1) ◽  
pp. 41-48
Author(s):  
Trisha Saha ◽  
Shamim Shamsi
Keyword(s):  
Azadirachta Indica ◽  
Pathogenic Fungi ◽  
Tagetes Erecta ◽  
Citrus Limon ◽  
Leaf Extracts ◽  
Houttuynia Cordata ◽  
Datura Metel ◽  
Houttuynia Cordata Thunb

Anthracnose and blight were recorded on Houttuynia cordata Thunb. during April 2013 to December 2013. The isolated fungi from the symptomatic plants were identified as Alterneria alternata (Fr.) Keissler and Colletotrichum gloeosporoides (Penz.) Sacc. Ethanol leaf extracts of five plants viz.,Azadirachta indica L., Citrus limon L., Datura metel L., Sennaalata L. and Tagetes erecta L.were evaluated against the pathogenic fungi A. alternata and C. gloeosporoides at 5%, 10% and 20% concentrations in vitro. A. indica recorded as good inhibitor against the test fungi followed by C. limon, S. alata, D. metel and T.erecta. In vivo treatment also showed that A.indica is the most effective in controlling diseases at 10% concentration. The plants treated with A. indica were fresh and healthy up to one month of observation.J. Asiat. Soc. Bangladesh, Sci. 42(1): 41-48, June 2016

scholarly journals Thlaspi arvense, a New Host for Alternaria brassicicola

Plant Disease ◽  
1998 ◽  
Vol 82 (8) ◽  
pp. 960-960 ◽  
Author(s):  
A. C. Cobb ◽  
H. R. Dillard
Keyword(s):  
Leaf Spot ◽  
Production Systems ◽  
Geographic Location ◽  
Alternaria Brassicicola ◽  
New Host ◽  
Cornell University ◽  
Thlaspi Arvense ◽  
Leaf Spots ◽  
Plastic Bags ◽  
Field Pennycress

A leaf spot was observed on cruciferous weeds growing in a cabbage field located in Geneva, NY, on 1 August 1996. The leaf spots on the weeds were dark gray to black in color and varied in size from pinpoints to 1 mm in diameter. The cabbage (Brassica oleracea L. var. capitata L.) was infected with Alternaria brassicicola (Schwein.) Wiltshire, the cause of Alternaria leaf spot. The weeds were identified as Thlaspi arvense L., a winter annual commonly referred to as field pennycress, stinkweed, or fanweed depending on geographic location. Isolations from the diseased weed tissue yielded A. brassicicola (2). The numerous conidia occurred in chains of 10 or more, ranged in size from 14 to 53 μm in length, were 5 to 18 μm wide, contained from 1 to 6 transverse septa with rare longitudinal septa, and were olivaceous in color. An apical beak was absent. On potato dextrose agar (PDA) the colony was dark olive-green to black in color and velvety. Seed was collected from the T. arvense plannts in the spring of 1997. One hundred seeds were placed in petri plates containing PDA amended with 0.01% of chloramphenicol and streptomycin sulfate. A. brassicicola was not isolated from the seeds. A different area of the field was planted to cabbage in 1997 and the cruciferous weeds were allowed to grow. The 1997 population of T. arvense consisted of plants from the previous season that flowered early and plants from seeds that germinated late in the season but did not flower. A. brassicicola was isolated from nonflowering weeds in September and from flowering weeds in October. Nonflowering plants were removed from the field in November, planted in pots, and placed in the greenhouse to induce flowering. Identity of both plant populations was confirmed as T. arvense (Warren Lamboy, Cornell University, Geneva, NY). Pathogencity of A. brassicicola isolates from T. arvense was demonstrated on cabbage and T. arvense by following Koch's postulates. Conidia (105) from a 5-day-old culture isolated from T. arvense grown on PDA were atomized onto field pennycress and cabbage plants with a Preval sprayer. The plants were enclosed in plastic bags and put under lathe shading in the greenhouse. The pathogen was reisolated from symptomatic tissue of both plants after 5 days. This weed could serve as a potential source of A. brassicicola inoculum because it is not controlled by herbicides used in crucifer production systems. Alternaria raphani has been reported on T. arvense in Canada (1). This is believed to be the first report of A. brassicicola on T. arvense. References: (1) K. Mortensen et al. Can. Plant Dis. Surv. 73:129, 1993. (2) P. Neergaard. 1945. Danish Species of Alternaria and Stemphylium. Oxford University Press, London. pp. 137–138.

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