scholarly journals First Report of Black Soft Rot of Indian Gooseberry Caused by Syncephalastrum racemosum

Plant Disease ◽  
2004 ◽  
Vol 88 (5) ◽  
pp. 575-575 ◽  
Author(s):  
Neelima Garg ◽  
Om Prakash ◽  
B. K. Pandey ◽  
B. P. Singh ◽  
G. Pandey
Keyword(s):  
Cellulase Activity ◽  
Basal Medium ◽  
Petri Dish ◽  
Soft Rot ◽  
Cellulolytic Activity ◽  
Academic Press ◽  
First Report ◽  
Syncephalastrum Racemosum ◽  
Indian Gooseberry ◽  
Pathogenicity Tests

Indian gooseberry (Emblica officinalis Gaertn.) is a medicinal plant with high nutraceutical value. During November and December 2003, soft rot was noticed on harvested and stored (20 ± 5°C and 65 ± 5% relative humidity) fruits at the experimental farm in Rehmanhera, Lucknow, India (26°50′N, 80°54′E). These fruits had numerous, minute brown necrotic lesions showing white mycelial growth. A pronounced halo of water-soaked, faded tissue surrounded the lesion between the fringe of mycelium and healthy tissues. The rotted surface was covered with a black, powdery layer of spores. On Czapek yeast extract agar, fungal colonies were blackish grey, moderately dense, and covered the entire petri dish. The fungus produced aseptate mycelium. The sporangial heads were 30 to 50 μm in diameter with sporangiospores found linearly within cylindrical sacs (merosporangia) borne on spicules around the columella. Sporangiospores, spherical to cylindrical in shape and borne in chains, measured 3.0 to 5.0 μm long. The fungus was morphologically and physiologically identified as Syncephalastrum racemosum Schr. (2). For pathogenicity tests, healthy fruits (10 replicates) were surface sterilized and punctured inoculated aseptically with 1.0 × 106 conidia and incubated at 20 ± 5°C Typical symptoms of the disease appeared after 4 days. The fungus exhibited a strong level of cellulolytic activity as indicated by prolific growth on Indian gooseberry fiber waste under solid-state fermentation conditions. The level of cellulase activity (1) was 21 filter paper activity unit per ml at 72 hr in culture supernatant of basal medium having carboxymethyl cellulose as the carbon source. The fungus showed resistance to tannins (as much as 2%), since it could grow well in liquid growth medium (Czapek Dox broth) with 2% tannins and aonla juice with 1.8% tannins. Since Indian gooseberry is rich in fiber (2.5 to 3.4%) and tannins (1.5 to 2.0%), this may be an important pathogen. To our knowledge, this is the first report of the occurrence of Syncephalastrum racemosum on Indian gooseberry fruits. References: (1) T. K. Ghose. Pure Appl. Chem. 59(2):257, 1987. (2) J. I. Pitt and A. D. Hocking. Fungi and Food Spoilage. Academic Press. North Ryde, Australia, 1985.

scholarly journals First Report of Leaf Blight Caused by Nigrospora sphaerica on Curcuma in China

Plant Disease ◽  
2011 ◽  
Vol 95 (9) ◽  
pp. 1190-1190
Author(s):  
L. X. Zhang ◽  
J. H. Song ◽  
G. J. Tan ◽  
S. S. Li
Keyword(s):  
Disease Incidence ◽  
Its Region ◽  
Leaf Blight ◽  
Morphological Data ◽  
Future Research ◽  
Leaf Margin ◽  
Academic Press ◽  
First Report ◽  
Pathogenicity Tests ◽  
Leaf Pathogen

Curcuma (family Zingiberaceae) is commonly cultivated for the use of rhizomes within traditional Chinese medicines. In October 2009 and 2010, severe leaf blight was observed on Curcuma wenyujin Y.H. Chen & C. Ling (4) in fields located in Ruian, China. The area of cultivation in Ruian encompasses 90% of the production in Zhejiang Province. Disease incidence was approximately 90% of plants observed in affected fields. Early symptoms were yellow-to-brown, irregular-shaped lesions on the leaf margin or tip. After several days, lesions expanded along the mid-vein until the entire leaf was destroyed. Blighted leaves turned grayish to dark brown and withered, and severely affected plants died. Eight fungal isolates were recovered from symptomatic C. wenyujin leaves, collected from eight different fields, on potato dextrose agar (PDA). These fungal colonies were initially white, becoming light to dark gray and produced black, spherical to subspherical, single-celled conidia (14 to 17 × 12 to 15 μm), which were borne on a hyaline vesicle at the tip of the conidiophores. On the basis of these morphological features, the isolates appeared to be similar to Nigrospora sphaerica (2). Strain ZJW-1 was selected as a representative for molecular identification. Genomic DNA was extracted from the isolate, and the internal transcribed spacer (ITS) region of the ribosomal DNA (ITS1-5.8S-ITS2) was amplified using ITS1 (5′-TCCGTAGGTGAACCTGCGG-3′) and ITS4 (5′-TCCTCCGCTTATTGATATGC-3′) primers (3). The ITS region was further cloned and sequenced (GenBank Accession No. JF738028) and was 99% identical to N. sphaerica (GenBank Accession No. FJ478134.1). On the basis of morphological data and the ITS rDNA sequence, the isolate was determined to be N. sphaerica. Pathogenicity tests were conducted on four leaves of four C. wenyujin plants by placing agar pieces (5 mm in diameter) from 8-day-old cultures on pushpin-wounded leaves. An equal number of control plants were wounded and inoculated with noncolonized PDA agar pieces. Plants were placed in moist chambers at 25°C with a 12-h photoperiod. Brown-to-black lesions were observed on wounded leaves after 3 days and expanded to an average of 56 × 40 mm 15 days after inoculation. No symptoms developed on the control leaves. The pathogen was reisolated from the margins of necrotic tissues but not from the controls. The pathogen has been reported as a leaf pathogen on several hosts worldwide (1). To our knowledge, this is the first report of N. sphaerica as a leaf pathogen of C. wenyujin in China. Future research will focus primarily on management of this disease. References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases, Systematic Mycology and Microbiology Laboratory, USDA-ARS, Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , March 31, 2011. (2) E. W. Mason. Trans. Brit. Mycol. Soc. 12:152, 1927. (3) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, 1990. (4) J. Zhao et al. Molecules 15:7547, 2010.

scholarly journals Pectobacterium carotovorum subsp. brasiliense Causes Soft Rot and Death of Neobuxbaumia tetetzo in Zapotitlan Salinas Valley, Puebla, Mexico

Plant Disease ◽  
2019 ◽  
Vol 103 (3) ◽  
pp. 398-403 ◽  
Author(s):  
Dimas Mejía-Sánchez ◽  
Sergio Aranda-Ocampo ◽  
Cristian Nava-Díaz ◽  
Daniel Teliz-Ortiz ◽  
Manuel Livera-Muñoz ◽  
...  
Keyword(s):  
Soft Rot ◽  
Genetic Identification ◽  
Pectobacterium Carotovorum ◽  
Bacterial Isolates ◽  
First Report ◽  
Whole Plant ◽  
Salinas Valley ◽  
Pathogenicity Tests ◽  
Carotovorum Subsp ◽  
Rdna Igs

Neobuxbaumia tetetzo (Coulter) Backeberg (tetecho) is a columnar cactus endemic to Mexico. Tetecho plants, flowers, fruits, and seeds play an important role in the semiarid ecosystem, as they serve as a refuge and food for insects, bats, and birds, and are widely used by ethnic groups since pre-Hispanic times. Tetecho is affected by a soft rot that damages the whole plant and causes its fall and disintegration. Eight bacterial colonies of similar morphology were isolated from plants showing soft rot and inoculated in healthy tetecho plants, reproducing typical symptoms of soft rot 9 days after inoculation. Ten representative isolates were selected for phenotypic and genetic identification using 16s rDNA, IGS 16S-23S rDNA, and rpoS genes and for pathogenicity tests on several members of the cactus family and other plants. Based on the results, these bacterial isolates were identified as Pectobacterium carotovorum subsp. brasiliense. Inoculation of this bacteria caused soft rot in different cacti, fruits, leaves, and roots of other plants. This is the first report of the subspecies brasiliense of P. carotovorum causing soft rot and death in cacti in the world and the first report of this subspecies in Mexico.

scholarly journals First Report of Fusarium solani Fruit Rot of Pumpkin (Cucurbita pepo) in Trinidad

Plant Disease ◽  
2009 ◽  
Vol 93 (5) ◽  
pp. 547-547
Author(s):  
S. N. Rampersad
Keyword(s):  
Fusarium Solani ◽  
Cucurbita Pepo ◽  
Morphological Characteristics ◽  
Soft Rot ◽  
The United States ◽  
Fruit Rot ◽  
Laboratory Manual ◽  
First Report ◽  
Pathogenicity Tests ◽  
Negative Controls

Trinidad is a major exporter of pumpkins (Cucurbita pepo L.) to other Caribbean countries, Canada, and the United States. Producers and exporters have reported 50 to 80% yield losses because of soft rot and overnight collapse of fruit at the pre- and postharvest stages. Severe fruit rot occurred in fields in Victoria County in South Trinidad between April and May 2006 (mid-to-late dry season) with an increase in the severity and number of affected fruit in the rainy season (July to December). Symptoms began as water-soaked lesions on the fruit of any age at the point of contact with the soil. The disease progressed to a soft rot with leakage and whole fruit collapse. A dark brown, soft decay also developed at the base of the main vines. Fusarium solani was isolated on selective fusarium agar and potato dextrose agar (PDA) (1) after 7 to 10 days of incubation at 25°C. The pathogen was identified by morphological characteristics and pathogenicity tests. Colonies were fast growing with white aerial mycelia and a cream color on the reverse side; hyphae were septate and hyaline, conidiophores were unbranched, and microconidia were abundant, thin walled, hyaline, fusiform to ovoid, generally one to two celled, and 8 to 10 × 2 to 4 μm. Macroconidia were hyaline, two to three celled, moderately curved, thick walled, and 25 to 30 × 4 to 6 μm. Pathogenicity tests for 10 isolates were conducted on 2-week-old pumpkin seedlings (cv. Jamaican squash; seven plants per isolate) and mature pumpkin fruit (2). Briefly, seedlings were inoculated by dipping their roots in a spore suspension (1 × 104 spores per ml) for 20 min. The plants were repotted in sterile potting soil. For negative controls, plant roots were dipped in sterile water. After the rind of fruit was swabbed with 70% ethanol followed by three rinses with sterile distilled water, 0.4-cm-diameter agar plugs of the isolates were inserted into wounds made with a sterile 1-cm-diameter borer. Sterile PDA plugs served as negative controls. Fruit were placed in sealed, clear, plastic bags. Inoculated plants and fruit were placed on greenhouse benches (30 to 32°C day and 25 to 27°C night temperatures) and monitored over a 30-day period. Tests were repeated once. Inoculated fruit developed a brown, spongy lesion that expanded from the initial wound site over a period of approximately 17 days after inoculation. White mycelia grew diffusely over the lesion. Inoculated plants developed yellow and finally necrotic leaves and lesions developed on stems at the soil line approximately 21 days after inoculation. No symptoms developed on the control plants. The fungus was reisolated from symptomatic tissue, fulfilling Koch's postulates. To my knowledge, this is the first report of Fusarium fruit rot of pumpkin in Trinidad. References: (1) J. Leslie and B. Summerell. Page 1 in: The Fusarium Laboratory Manual. Blackwell Publishing, Oxford, 2006. (2) W. H. Elmer. Plant Dis. 80:131, 1996.

scholarly journals First Report of Soft Rot Caused by Aspergillus niger sensu lato on Mother-in-law’s Tongue in China

Plant Disease ◽  
2020 ◽  
Author(s):  
Siliang Huang ◽  
Xue Ling Zheng ◽  
Di Yang ◽  
Jinping An ◽  
Lu Wang ◽  
...  
Keyword(s):  
Aspergillus Niger ◽  
Phylogenetic Tree ◽  
Soft Rot ◽  
Leaf Margin ◽  
Strict Sense ◽  
Tubulin Gene ◽  
First Report ◽  
Rdna Its ◽  
Pathogenicity Tests ◽  
Β Tubulin

“Mother-in-law’s tongue” (MLT) [Dracaena trifasciata (Prain) Mabb. (syn. Sansevieria trifasciata Prain.)], also known as “Saint George's sword", “snake plant”, “tiger's tail orchid", etc., is an evergreen perennial ornamental plant grown worldwide. In September 2016, severe soft rot occurred on the leaves of MLT in a flower market in Nanyang city (32º56´N, 112º32´E), Henan province, China with 25% disease incidence (n=100). Water-soaked spots initially appeared on the leaf margin, enlarged rapidly, and became soft rot under excessively watered conditions. A blight zone was visualized at the margin of a developing lesion in backlit conditions. Severely affected leaves folded down from the lesions. Lesion expansion stopped under dry conditions. Grey or dark brown mycelia were frequently seen on the lesions. Tissue pieces (4×4 mm2) at the margin of lesions were cut out, treated with 75% ethanol for 10 s, followed by 70 s in 0.1% HgCl2, rinsed eight times with sterile water, and plated on potato dextrose agar (PDA) medium. Pure Aspergillus cultures were obtained from the surface-disinfected lesions after 4 days of incubation at 26°C. Two single-spore-derived isolates (An-1 and An-2) were randomly selected and used for morphological and molecular identifications as well as pathogenicity tests. The isolates formed round dark brown colonies with a large number of conidia after 5 days of incubation on PDA at 28°C. Conidia were subsphaeroidal or oblate, unicellular, dark brown, 2.9-4.2(3.5) × 1.9-3.4(2.7) μm in size (n=100), developed from a two-series of strigmata born on a conidial head, with ridge or stab-shaped prominences. For pathogenicity tests, the two isolates were separately grown on oatmeal agar and incubated at 30°C for 6 days. Mycelial plugs (5 mm diam.) were inoculated on the scalpel incision X-shaped wounds of surface-disinfected leaves of MLT. The inoculated leaves were kept on a two-layer of wet napkin in a steel basin covered with a plastic film. Soft rot symptoms developed from the wounds 6 days after incubation, similar to those observed on naturally affected leaves. The An-1- and An-2-inoculated unwounded leaves remained symptomless during the pathogenicity tests. Fungal cultures with the same phenotypes as the inocula were consistently reisolated from the lesions of the leaves inoculated by each of the two isolates, verifying the isolates as the causal agent of the disease based on Koch’s postulates. Both β-tubulin gene and rDNA-ITS (internal transcribed spacer) sequences of the two isolates were separately amplified and sequenced. Sequences were submitted to GenBank with accession numbers MN259522 and MN259523 for the β-tubulin gene sequences, and accession numbers MN227322 and MN227324 for the rDNA-ITS sequences of An-1 and An-2, respectively. Both An-1 and An-2 were clustered with members of Aspergillus niger van Tieghem in the phylogenetic tree of rDNA-ITS, clearly separated from other Aspergillus spp. In the phylogenetic tree of β-tublin gene, both An-1 and An-2 formed a subclade inside a large clade consisting of members of A. niger in strict sense. Based on the molecular and morphological results, both An-1 and An-2 clearly separated from other Aspergillus spp. and can be considered as A. niger sensu lato. Foliar diseases of MLT are known to be caused by a few fungal species such as Chaetomella spp. (Li et al. 2014) and Colletotrichum sansevieriae (Nakamura et al. 2006). This is the first report of A. niger sensu lato causing soft rot on MLT in China.

scholarly journals First Report of the Anamorph of Glomerella acutata Causing Anthracnose on Avocado Fruits in Mexico

Plant Disease ◽  
2007 ◽  
Vol 91 (9) ◽  
pp. 1200-1200 ◽  
Author(s):  
G. Avila-Quezada ◽  
H. V. Silva-Rojas ◽  
D. Teliz-Ortiz
Keyword(s):  
Colletotrichum Gloeosporioides ◽  
Soft Rot ◽  
Lower Surface ◽  
Persea Americana ◽  
Colletotrichum Acutatum ◽  
Morphological Identification ◽  
Internal Transcribed Spacer Region ◽  
First Report ◽  
Mexican State ◽  
Pathogenicity Tests

Mexico is a major avocado (Persea americana) producer in the world. Glomerella cingulata (anamorph Colletotrichum gloeosporioides) has been reported as a causal agent of anthracnose on avocado fruits worldwide (3), while G. acutata (anamorph Colletotrichum acutatum) has been identified as the cause of this disease only in New Zealand (2) and Australia (4). This study was done with the objective to determine the Glomerella spp. involved as the causal agents of avocado anthracnose in Mexico. From 2003 to 2006, avocado fruits cv. Hass with anthracnose symptoms appearing as brown-black lesions on the pericarp and soft rot in the mesocarp were collected in 10 counties in Michoacan, the leading avocado-producing Mexican state. Glomerella spp. were isolated on potato dextrose agar (PDA) for molecular and morphological identification. A phylogenetic analysis was done by amplifying the internal transcribed spacer region of rDNA for 28 of the isolates. Primers ITS5/NL4 was used and successfully amplified bands of approximately 1,000 bp. Each sequence corresponding to Glomerella spp. was compared with sequences deposited in the GenBank database using BLAST. The results from molecular approach indicated 86% of the isolates used in this study were G. cingulata and 14% were G. acutata. Sequences of both species were deposited in GenBank under Accession Nos. EF221828, EF221829, and EF221830 for G. cingulata and EF175780, EF221831, and EF221832 for G. acutata. Colonies of G. acutata that developed on PDA medium were pale gray, occasionally the lower surface was olive green, and the center was covered with orange-to-salmon pink masses of conidia and perithecia. Conidia grown in the same media were straight, fusiform, 8.2 to 16.5 μm long, and 2.7 to 4.0 μm wide (4). Pathogenicity tests of G. acutata were carried out by inoculating six healthy cv. Hass fruits (1) at three evenly spaced locations on the fruit surface with a needle dipped in a conidial mass from a 3-day-old monoconidial culture of G. acutata. Fruits were then incubated in a moist chamber for 3 days. Anthracnose symptoms were observed on healthy fruits inoculated with G. acutata, while control fruits inoculated with sterile water did not develop symptoms. The fungi were reisolated successfully to confirm the pathogen's identity using morphological key. To our knowledge, this is the first report of G. acutata causing anthracnose on avocado fruits in Mexico. References: (1) R. Guetsky et al. Phytopathology 95:1341, 2005. (2) W. F. T. Hartill. N. Z. J. Crop Hortic. Sci. 19:297, 1991. (3) D. Prusky. Annu. Rev. Phytopathol. 34:413, 1996. (4) J. H. Simmonds. Qld. J. Agric. Anim. Sci. 22:437, 1965.

scholarly journals First Report of Soft Rot of Potatoes Caused by Dickeya dadantii in Zimbabwe

Plant Disease ◽  
2010 ◽  
Vol 94 (10) ◽  
pp. 1263-1263 ◽  
Author(s):  
E. Ngadze ◽  
T. A. Coutinho ◽  
J. E. van der Waals
Keyword(s):  
Sequence Analysis ◽  
Solanum Tuberosum L ◽  
Pcr Amplification ◽  
Soft Rot ◽  
Economic Losses ◽  
Dickeya Dadantii ◽  
First Report ◽  
Gyrb Sequence ◽  
Pathogenicity Tests ◽  
Import And Export

A survey was carried out in the potato- (Solanum tuberosum L.) growing regions of Zimbabwe in April 2009 to assess the prevalence of bacterial soft rot. A total of 125 tubers with soft rot symptoms were collected. The disease caused severe economic losses ranging from 20 to 60% on tubers in the field and in storage. Affected tubers had symptoms that ranged from light vascular discoloration to complete seed piece decay. Infected tuber tissue was often cream colored and soft to the touch. In the field, plants showed severe wilting, often accompanied by a slimy, brown necrosis of the lower stems. Seventy-five of 125 isolations from diseased tubers yielded pectolytic bacteria on crystal violet pectate (CVP) medium and colonies were characterized after purification on King's B medium. All 75 isolates were gram-negative rods, oxidase negative, facultatively anaerobic, able to degrade pectate, and rot potato slices. They grew at 37°C, were sensitive to erythromycin, positive for phosphatase, indole production, cis-aconitate, lactose, d-arabinose, meso-tartrate, casein, d-melibiose, myo-inositol, and malonate utilization, while negative for acid production from trehalose, inuline, and α-methyl glucose. Dickeya dadantii (Erwinia chrysanthemi 3937 from the Scottish Research Institute) was included in all biochemical and pathogenicity tests. These characteristics are typical for two species, D. zeae and D. dadantii (2). Thus, the 75 isolates were further identified by PCR amplification with BOX and REP primers (3) and five isolates by gyrB sequence analysis (1). These analyses give support for the isolates being D. dadantii. Partial gyrB sequence analysis showed that the analyzed isolates had 96% sequence identity with the D. dadantii type strain Ech 586T (GenBank Accession No. CP001836.1). One-microliter suspensions (108 CFU per ml) of 20 samples were injected into the stolon end of potato tubers (S. tuberosum L.) cv. BP1. Each isolate was inoculated into three tubers, which were maintained at 25°C. Three control tubers were inoculated with sterile distilled water. Soft rot symptoms identical to those observed in the field and in storage appeared on all inoculated tubers 1 to 2 days after inoculation but not on the control tubers. A bacterium with identical characteristics to those described above was consistently reisolated from the rotted tissue of inoculated tubers. To our knowledge, this is the first report of soft rot on potato in Zimbabwe caused by D. dadantii, formerly referred to as E. chrysanthemi. This finding has implications for import and export of potato material into and out of Zimbabwe. Zimbabwe imports seed from various countries because of the current seed shortage and exports table potatoes to other African states. References: (1) C. Brady et al. Int. J. Syst. Evol. Micobiol. 59:2339, 2009. (2) R. Samson et al. Int. J. Syst. Evol. Microbiol. 55:1415, 2005. (3) J. Versalovic et al. 1991. Nucleic Acids Res. 19:6823, 1991.

scholarly journals First Report of Choanephora Flower Spot and Blight of Periwinkle

Plant Disease ◽  
1998 ◽  
Vol 82 (4) ◽  
pp. 447-447 ◽  
Author(s):  
G. E. Holcomb
Keyword(s):  
Baton Rouge ◽  
Soft Rot ◽  
Fluorescent Light ◽  
High Humidity ◽  
First Report ◽  
Variety Trial ◽  
Choanephora Cucurbitarum ◽  
Pathogenicity Tests ◽  
White Mycelium ◽  
Commercial Landscape

Periwinkle or vinca (Catharanthus roseus (L.) G. Don) is widely planted as a flowering annual in home and business landscapes in hardiness zones 9 and 10 and the southernmost portions of zone 8. Many improved selections, such as those in the Pacifica, Tropicana, and Cooler cultivar series, are currently available. Dark gray flower spots that often coalesced and led to blighting of flowers under conditions of high humidity, were observed on all of 18 periwinkle cultivars in a variety trial at Burden Research Plantation in September 1997. The disease affected only the flowers and was also observed on periwinkle in commercial landscape plantings around Baton Rouge. Fungi were isolated from flower spots by plating necrotic tissue on acidified potato dextrose agar (PDA). Fungal isolates were maintained on PDA and 20% V8 juice agar under continuous fluorescent light. A fungus that produced cottony, white mycelium and black spore masses was consistently isolated from diseased tissue. Pathogenicity tests were conducted by misting a spore suspension (70,000 per ml produced on V8 juice agar) onto detached flowers held in a moist chamber and to flowers on intact plants. Inoculated plants were held for 24 h in a dew chamber at 25°C. Typical irregular dark spots appeared on attached and detached flowers within 18 h after inoculation and flowers held for longer periods under high humidity developed a soft rot. Koch's postulates were fulfilled by reisolating the fungal pathogen, which was identified as Choanephora cucurbitarum (Berk. & Ravenel) Thaxt. (1). This is the first report of the occurrence of C. cucurbitarum on periwinkle. Reference: (1) P. M. Kirk. Mycol. Pap. 152:1, 1984.

scholarly journals First Report of Leaf Spot of Saponaria officinalis Caused by Alternaria nobilis in Italy

Plant Disease ◽  
2013 ◽  
Vol 97 (3) ◽  
pp. 424-424 ◽  
Author(s):  
A. Garibaldi ◽  
D. Bertetti ◽  
A. Poli ◽  
M. L. Gullino
Keyword(s):  
Morphological Characteristics ◽  
Pathogenicity Test ◽  
Academic Press ◽  
First Report ◽  
Perennial Plant ◽  
Plastic Bags ◽  
Pcr Product ◽  
Pathogenicity Tests ◽  
Alternaria Sp ◽  
Saponaria Officinalis

Saponaria officinalis (Vize) Simmons (common name bouncingbet) is a low maintenance perennial plant belonging to the Caryophyllaceae family, typically grown in parks and gardens. During the summers of 2011 and 2012, extensive necrosis were observed on leaves of plants grown in private gardens, near Biella (northern Italy). The disease affected 90% of 1- to 2-year-old plants. The first symptoms were usually pale brown lesions 1 to 5 mm in diameter and sometimes coalesced. Lesions were circular to irregular with a dark purple halo, with infected leaves eventually turning chlorotic. The conidia observed on infected leaves were olivaceous brown and obclavate, with a beak. Conidia showed 8 to 15 (average 12) transverse and 4 to 14 (average 11) longitudinal septa, with slight constrictions connected with septa, and were 78.3 to 177.7 (average 135.5) × 19.0 to 34.3 (average 26.5) μm. The beak was 20.0 to 62.2 (average 33.7) μm in length, with 0 to 6 (average 3) transverse septa and no longitudinal septa. The fungus was consistently isolated from infected leaves on potato dextrose agar (PDA). The isolate, grown for 14 days at 20 to 24°C with 10 h of darkness and 14 h of light on sterilized host leaves plated on PDA, produced conidiophores single, unbranched, flexuous, septate with conidia in short chains, similar to those observed on the leaves and previously described. On the basis of its morphological characteristics, the pathogen was identified as Alternaria sp. (3). DNA was extracted using Nucleospin Plant Kit (Macherey Nagel) and PCR carried out using ITS 1/ITS 4 primer (4). A 542-bp PCR product was sequenced and a BLASTn search confirmed that the sequence corresponded to A. dianthi (AY154702), recently renamed A. nobilis (2). The nucleotide sequence has been assigned the GenBank Accession No. JX647848. Pathogenicity tests were performed by spraying leaves of healthy 3-month-old plants of S. officinalis with an aqueous 2 × 105 spore/ml suspension. The inoculum was obtained from cultures of the fungus grown on PDA amended with host leaves for 14 days, in light-dark, at 22 ± 1°C. Plants sprayed only with water served as controls. Four pots (1 plant/pot) were used for each treatment. Plants were covered with plastic bags for 4 days after inoculation and maintained in a glasshouse at 21 ± 1 °C. Lesions developed on leaves 9 days after inoculation with the spore suspension, whereas control plants remained healthy. A. nobilis was consistently reisolated from these lesions. The pathogenicity test was carried out twice. The presence of A. dianthi was reported on S. officinalis in Denmark (1) and Turkey. This is, to our knowledge, the first report of A. nobilis on S. officinalis in Italy. The presence and importance of this disease is, at present, limited. References: (1) P. Neergaard. Danish species of Alternaria and Stemphylium. Oxford University Press, 1945. (2) E. G. Simmons. Mycotaxon 82:7, 2002. (3) E. G. Simmons. Alternaria: An Identification Manual. CBS Biodiversity Series 6, Utrecht, The Netherlands, 2007. (4) T. J. White et al. In: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, 1990.

scholarly journals First Report of Phytophthora sansomeana Causing Wilting and Stunting on Corn in Ohio

Plant Disease ◽  
2010 ◽  
Vol 94 (1) ◽  
pp. 125-125 ◽  
Author(s):  
L. X. Zelaya-Molina ◽  
M. L. Ellis ◽  
S. A. Berry ◽  
A. E. Dorrance
Keyword(s):  
United States ◽  
Growth Rate ◽  
Morphological Characteristics ◽  
Petri Dish ◽  
The United States ◽  
The State ◽  
Its Sequence ◽  
First Report ◽  
Its Sequence Analysis ◽  
Pathogenicity Tests

During the spring of 2004, corn seedlings with symptoms of wilting and stunting were observed in corn fields with emergence problems in Madison and Brown counties, Ohio. Phytophthora isolates were recovered from sections of root tissue of diseased seedlings placed on dilute V8 media amended with pentachloronitrobenzene, iprodione, benlate, neomycin sulfate, and chloramphenicol. Colonies were rosaceous on potato dextrose agar, with a growth rate of 5 mm per day. Homothallic isolates with paragynous antheridia were observed on lima bean agar (LBA); oogonia were 35 to 50 μm in diameter. Sporangia were ovoid to obpyriform, nonpapillate, with an average size of 49 × 30 μm. Pathogenicity was tested on corn seeds using a petri dish assay with 3-day-old cultures on LBA and a sand-cornmeal cup test amended with inoculum from 7-day-old cultures on LBA (1). After 1 week in the petri dish assay, the seeds failed to germinate completely and were covered with white, fungal-like, aerial mycelia and the pathogen was recovered from brown discolored radicle roots. In the cup assay, 2-week-old seedlings developed the same symptoms observed in the field; the pathogen was also isolated from brown discolored roots. In both assays, no symptoms developed in the noninoculated controls. Both pathogenicity tests were repeated two times. Genomic DNA was extracted from mycelia of two isolates and the internal transcribed spacer (ITS) region was amplified and sequenced using ITS6/ITS4 primers (2). Both isolates had identical ITS sequences (GenBank Accession No. GQ853880). A BLAST search of the NCBI database showed 100% homology with the sequence of the haplotype isolate of Phytophthora sansomeana (Accession No. EU925375). P. sansomeana is a new species characterized principally by a large oogonial diameter (37 to 45 μm), rapid growth rate (7 to 10 mm/day), and an ITS sequence falling in Cooke's clade 8 (4). Pathogenicity tests, morphological characteristics, and the ITS sequence analysis indicate that P. samsomena is the causal agent of the symptoms observed on corn seedlings. P. sansomeana has been reported as a pathogen of soybean in Indiana, Douglas-fir in Oregon, and weeds in alfalfa fields in New York (4). To our knowledge, this is the first report of P. sansomeana infecting corn in Ohio, albeit other isolates have previously been recovered from soybean in the state. There are four previous reports of Phytophthora spp. affecting corn in the United States and Mexico (3). Crop rotation will have little effect in management of this pathogen since corn and soybean are produced in the same fields continuously throughout the state. References: (1) K. E. Broders et al. Plant. Dis. 91:727, 2007. (2) D. E. L. Cooke et al. Fungal Genet. Biol. 30:17, 2000. (3) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, St. Paul, MN. 1989. (4) E. M. Hansen et al. Mycologia 101:129, 2009.

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