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 Damping-off Caused by Pythium aphanidermatum on Leaf Beet (Beta vulgaris subsp. vulgaris) in Italy

Plant Disease ◽  
2013 ◽  
Vol 97 (2) ◽  
pp. 292-292 ◽  
Author(s):  
A. Garibaldi ◽  
G. Gilardi ◽  
G. Ortu ◽  
M. L. Gullino
Keyword(s):  
Beta Vulgaris ◽  
Its Region ◽  
Soft Rot ◽  
Pythium Aphanidermatum ◽  
Morphological Characters ◽  
Fluorescent Light ◽  
Damping Off ◽  
First Report ◽  
Pathogenicity Tests ◽  
Crown And Root Rot

During July 2010, symptoms of crown and root rot were observed on leaf beet (Beta vulgaris L. subsp. vulgaris) grown in a commercial field near Torino (northern Italy). The first symptoms developed 25 days after sowing with temperatures ranging from 25 to 30°C, and 20% of plants were affected. Affected plants were stunted and leaves showed chlorosis and suddenly wilted. The collar and young stems were affected first and appeared brown, water-soaked, and were characterized by a soft rot. Eventually, all affected plants collapsed. Thin aerial mycelia were visible on the surface of the infected plants if maintained at a high relative humidity. Tissue fragments of 1 mm2 were excised from the margins of the lesions, dipped in a solution containing 1% sodium hypochlorite, and plated on potato dextrose agar (PDA) and on a medium selective for oomycetes (2). Plates were incubated under constant fluorescent light at 22 ± 1°C for 5 days. Five isolates, grown on V8 medium (vegetable mix 300 g; agar 15 g; CaCO3 1.5 g; distilled water 1 liter) and observed under light microscope showed the morphological characters of Pythium aphanidermatum (3). This result was confirmed by PCR and sequence analysis. The internal transcribed spacer (ITS) region of rDNA of a single isolate (Py 7/10) was amplified using the primers ITS1/ITS4 and sequenced. BLAST analysis (1) of the 815 bp segment showed a 99% homology with the sequence of P. aphanidermatum (GenBank Accession JN695786). The nucleotide sequence has been assigned to the GenBank Accession JX462954. Pathogenicity tests were performed twice on B. vulgaris subsp. vulgaris grown in 2-liter pots, containing a steam disinfested organic peat substrate (70% black peat, 30% white peat, pH 5.5 to 6, N 110 to 190 mg L–1, P2O5 140 to 230 mg L–1, K2O 170 to 280 mg L–1), infested with wheat and hemp kernels colonized with a strain of P. aphanidermatum at a rate of 1 g L–1. Ten seeds per pot were sown in four pots filled with the infested medium, while the same number of seeds were sown in non-infested substrate. Plants were kept in two growth chambers, at 20 and 27°C. The first symptoms developed 7 days after the artificial inoculation. After 20 days, 70% of plants were infected at 27°C, while 10% were affected at 20°C. Control plants remained healthy at both temperatures. P. aphanidermatum was consistently reisolated from the lesions. To our knowledge, this is the first report of damping off of B. vulgaris subsp. vulgaris caused by P. aphanidermatum in Italy. The importance of the disease, at present limited, could increase in areas where leaf beet is intensively grown. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) H. Masago et al. Phytopathology 67:425, 1977. (3) T. Watanabe. Pictorial Atlas of Soil and Seed Fungi. CRC Press, Florida, 2002.

scholarly journals First Report of Sclerotinia Stem Rot and Watery Soft Rot Caused by Sclerotinia sclerotiorum on Sand Rocket (Diplotaxis tenuifolia) in Italy

Plant Disease ◽  
2005 ◽  
Vol 89 (11) ◽  
pp. 1241-1241 ◽  
Author(s):  
A. Garibaldi ◽  
A. Minuto ◽  
M. L. Gullino
Keyword(s):  
Relative Humidity ◽  
Sclerotinia Sclerotiorum ◽  
Severe Disease ◽  
Soil Surface ◽  
Soft Rot ◽  
Sclerotinia Stem Rot ◽  
First Report ◽  
Initial Symptoms ◽  
Stem Necrosis ◽  
White Mycelium

Several species of Diplotaxis (D. tenuifolia, D. erucoides, and D. muralis), known as wild or sand rocket, are widely cultivated in Italy. Rocket is used in Mediterranean cuisine as salad, a component of packaged salad products, and as a garnish for food. In winter 2003, a severe disease was observed on D. tenuifolia grown in unheated glasshouses on commercial farms near Albenga in northern Italy. Initial symptoms included stem necrosis at the soil level and darkening of leaves. As stem necrosis progressed, infected plants wilted and died. Wilt, characterized by the presence of soft and watery tissues, occurred within a few days on young plants. The disease was extremely severe in the presence of high relative humidity and mild temperature (15°C). Necrotic tissues became covered with white mycelium that produced dark sclerotia. Diseased stem tissue was disinfested for 1 min in 1% NaOCl and plated on potato dextrose agar (PDA) amended with 100 ppm streptomycin sulfate. Sclerotinia sclerotiorum (1) was consistently recovered from infected stem pieces. Sclerotia observed on infected plants measured 1.23 to 3.00 × 1.40 to 5.38 mm (average 2.10 × 2.85 mm). Sclerotia produced on PDA measured 1.00 to 4.28 × 1.00 to 6.01 mm (average 2.38 × 3.23 mm). Pathogenicity of three isolates obtained from infected plants was confirmed by inoculating 30-day-old plants of D. tenuifolia grown in 18-cm-diameter pots in a glasshouse. Inoculum, 2 g per pot of wheat kernels infested with mycelium and sclerotia of each isolate, was placed on the soil surface around the base of each plant. Three replicates of five pots each were used per isolate. Noninoculated plants served as controls. The inoculation trial was repeated once. All plants were kept at temperatures ranging between 10 and 26°C (average 15°C) with an average relative humidity of 80% and were watered as needed. Inoculated plants developed symptoms of leaf yellowing within 12 days, soon followed by the appearance of white mycelium and sclerotia, and eventually wilted. Control plants remained symptomless. S. sclerotiorum was reisolated from inoculated plants. To our knowledge, this is the first report of infection of D. tenuifolia by S. sclerotiorum in Italy as well as worldwide. The disease currently has been observed in the Liguria Region but not yet in other areas where sand rocket is cultivated. The economic importance of this disease for the crop can be considered medium at the moment, but is expected to increase in the future. Reference: (1) N. F. Buchwald. Den. Kgl. Veterin.er-og Landbohojskoles Aarsskrift, 75, 1949.

scholarly journals First Report of Gray Leaf Spot on St. Augustinegrass in Italy

Plant Disease ◽  
2003 ◽  
Vol 87 (12) ◽  
pp. 1536-1536 ◽  
Author(s):  
G. Polizzi ◽  
I. Castello ◽  
A. M. Picco ◽  
D. Rodino
Keyword(s):  
Leaf Spot ◽  
Magnaporthe Grisea ◽  
Fungal Spore ◽  
Gray Leaf Spot ◽  
Blast Disease ◽  
Leaf Spot Disease ◽  
High Humidity ◽  
Conidial Suspension ◽  
First Report ◽  
Pathogenicity Tests

St. Augustinegrass (Stenotaphrum secundatum (Walt.) Kuntze) is used for lawns in southern Italy because it is much more resistant to biotic and abiotic adversities than other turfgrass species. Because few seeds are viable, this species is established by vegetative propagation. A new disease was noticed during the spring of 2002 and 2003 on cuttings of St. Augustinegrass growing in three greenhouses in eastern Sicily. The disease affected leaves and culms and caused a progressive drying of the plants. The infection was first seen on leaves as gray, necrotic spots that enlarged in high-humidity conditions to form oval, and later, spindle-shaped lesions. In association with the lesions, it was possible to observe fungal spore development and sunken areas with blue-gray centers and slightly irregular, brown margins with yellow halos. Spots were concentrated without specific arrangement along longitudinal veins and the midrib and at the base, tip, and margins of the leaf blade. Symptoms on the culms consisted of brown-to-black blotches that sometimes extended throughout the internodes. From these infected tissues, 20 explants taken from leaves and culms were cut, washed with sterile water, and placed on 1.5% water agar (WA). Later, conidia and conidiophores were obtained from colonies with a sterile glass needle and placed on 4% WA. From these plates, two monoconidial isolates were obtained and transferred to rice meal medium (1). The colonies were identified as Pyricularia grisea Cooke (Sacc.), anamorphic state of Magnaporthe grisea (Hebert) Yeagashi & Udagawa, the cause of rice blast disease and gray leaf spot disease of turfgrasses. The conidia were pyriform to obclavate, narrowed toward the tip, rounded at the base, 2-septate, 21 to 31 μm × 6 to 10 μm (average 25.7 ×8.2 μm). Pathogenicity tests were performed by inoculating leaves and culms of six St. Augustinegrass plants with a conidial suspension of the fungus (1.5 ×105 conidia per ml). The same number of noninoculated plants was used as controls. All plants were incubated in a moist chamber with high humidity at 25°C. After 6 days, all inoculated plants showed typical symptoms of the disease. Koch's postulates were fulfilled by isolating P. grisea from inoculated plants. Gray leaf spot caused by P. grisea has been a chronic problem on St. Augustinegrass since it was first reported in 1957 (2). To our knowledge, this is the first report of P. grisea on St. Augustinegrass in Italy. While it does not appear to be an important disease in the field at this time in Sicily, it could cause losses in greenhouses where vegetative material is propagated for field planting. A preliminary molecular analysis has shown a clear distinction between the tested strain and other strains isolated from rice seeds and plants in northern Italy. References: (1) E. Roumen et al. Eur. J. Plant Pathol. 103:363, 1997. (2) L. P. Tredway et al. Plant Dis. 87:435, 2003.

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 Sclerotium rolfsii on Catharanthus roseus

Plant Disease ◽  
2000 ◽  
Vol 84 (2) ◽  
pp. 200-200
Author(s):  
G. E. Holcomb
Keyword(s):  
Catharanthus Roseus ◽  
Fungal Pathogen ◽  
Baton Rouge ◽  
Sclerotium Rolfsii ◽  
The United States ◽  
Madagascar Periwinkle ◽  
Basal Stem Rot ◽  
First Report ◽  
Pathogenicity Tests ◽  
Stem Necrosis

Wilt, blight, and stem necrosis were observed on Catharanthus roseus (L.) G. Don ‘Mediterranean Deep Rose’ (MDR) plants (Madagascar or rose periwinkle) in August 1999 at Burden Research Plantation in Baton Rouge, LA. MDR was the only prostrate-form cultivar and the only cultivar of 11 that was diseased. Twelve of twenty-four plants of cv. MDR were killed in the trial planting. White mycelia and small (1 mm diameter) light brown sclerotia were present at the base of infected plants. The suspect fungus was isolated consistently on acidified water agar and maintained on acidified potato dextrose agar (APDA). Pathogenicity tests were done by pipetting 1 ml of blended inoculum (contents of one 7-day-old plate culture grown on APDA in 100 ml of deionized water) at the base of nine 15-cm-tall Madagascar periwinkle plants. Inoculated and noninoculated plants were held in a dew chamber for 3 days at 28°C and placed in a greenhouse where temperatures ranged between 25 and 31°C. All inoculated plants showed wilt, blight, and basal stem rot after 3 days and were dead after 10 days. Noninoculated plants remained symptomless. The fungal pathogen was identified as Sclerotium rolfsii Sacc. and was reisolated from inoculated plants. The fungus was previously reported on Lochnera rosea (L.) Rchb. (=C. roseus) from Taiwan (1). This is the first report of the occurrence of S. rolfsii on Madagascar periwinkle in the United States. Reference: (1) K. Goto. Trans. Nat. Hist. Soc. Formosa 23:37, 1933.

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 Crown and Root Rot Caused by Rhizoctonia solani AG-4 on Banana Passionflower (Passiflora mollissima) in Italy

Plant Disease ◽  
2011 ◽  
Vol 95 (9) ◽  
pp. 1194-1194 ◽  
Author(s):  
G. Polizzi ◽  
D. Aiello ◽  
V. Guarnaccia ◽  
A. Panebianco ◽  
P. T. Formica
Keyword(s):  
Rhizoctonia Solani ◽  
Root Rot ◽  
Disease Incidence ◽  
Morphological Characteristics ◽  
Fluorescent Light ◽  
Disease Symptoms ◽  
First Report ◽  
Pathogenicity Tests ◽  
Crown And Root Rot ◽  
Safranin O

The genus Passiflora (Passifloraceae family) contains more than 500 species and several hybrids. In Italy, some of these species and hybrids are grown as ornamental evergreen vines or shrubs. During August and September 2010, a crown and root rot was observed in a stock of approximately 6,000 potted 2-year-old plants of Passiflora mollissima (Kunth) Bailey, commonly known as the banana passionflower, in a nursery located in eastern Sicily (southern Italy). Disease incidence was approximately 20%. Disease symptoms consisted of water-soaked lesions at the crown and a root rot. Successively, older crown lesions turned light brown to brown and expanded to girdle the stem. As crown and root rot progressed, basal leaves turned yellow and gradually became necrotic and infected plants wilted and died. A fungus with mycelial and morphological characteristics of Rhizoctonia solani Kühn was consistently isolated from crown lesions and brown decaying roots when plated on potato dextrose agar (PDA) amended with streptomycin sulfate at 100 μg/ml. Fungal colonies were initially white, turned brown with age, and produced irregularly shaped, brown sclerotia. Mycelium was branched at right angles with a septum near the branch with a slight constriction at the branch base. Hyphal cells removed from 10 representative cultures grown at 25°C on 2% water agar were determined to be multinucleate when stained with 1% safranin O and 3% KOH solution (1) and examined at ×400. Anastomosis groups were determined by pairing isolates on 2% water agar in petri plates (4). Pairings were made with tester strains of AG-1, AG-2, AG-3, AG-4, AG-5, AG-6, and AG-11. Anastomosis was observed only with tester isolates of AG-4 (3). Pathogenicity tests were performed on container-grown, healthy, 3-month-old cuttings. Twenty plants of P. mollissima were inoculated near the base of the stem with five 1-cm2 PDA plugs from 5-day-old mycelial plugs obtained from two representative cultures. The same number of plants served as uninoculated controls. Plants were maintained at 25°C and 95% relative humidity with a 12-h fluorescent light/dark regimen. Wilt symptoms due to crown and root rot, identical to ones observed in the nursery, appeared 7 to 8 days after inoculation with either of the two isolates and all plants died within 20 days. No disease was observed on control plants. R. solani AG-4 was reisolated from symptomatic tissues and identified as previously described, confirming its pathogenicity. Damping-off or crown and root rot due to R. solani were previously detected on P. edulis in Brazil, Africa, India, Oceania, and Australia (2). To our knowledge, this is the first report of R. solani causing crown and root rot on P. mollissima. References: (1) R. J. Bandoni. Mycologia 71:873, 1979. (2) J. L. Bezerra and M. L. Oliveira. Fitopathol. Brasil. 9:273, 1984. (3) D. E. Carling. Page 37 in: Grouping in Rhizoctonia solani by Hyphal Anastomosis Reactions. Kluwer Academic Publishers, the Netherlands, 1996. (4) C. C. Tu and J. W. Kimbrough. Mycologia 65:941, 1973.

scholarly journals First Report of a New Leaf Spot Caused by Plectosphaerella cucumerina on Field Grown Endive (Cichorium endivia) in Italy

Plant Disease ◽  
2013 ◽  
Vol 97 (6) ◽  
pp. 848-848 ◽  
Author(s):  
A. Garibaldi ◽  
G. Gilardi ◽  
G. Ortu ◽  
M. L. Gullino
Keyword(s):  
Leaf Spot ◽  
Economic Losses ◽  
Leaf Spot Disease ◽  
Fluorescent Light ◽  
Conidial Suspension ◽  
Fresh Market ◽  
First Report ◽  
Cichorium Endivia ◽  
Pathogenicity Tests ◽  
Plectosphaerella Cucumerina

During summer 2012, symptoms of a new leaf spot disease were observed in several commercial fields in Treviglio (Bergamo, northern Italy) on plants of curly (Cichorium endivia var. crispum) and Bavarian (C. endivia var. latifolium) endive (Asteraceae). This crop is widely grown in the region for fresh market. The first symptoms on leaves of affected plants consisted of small (1 mm) black-brown spots of irregular shape, later coalescing into larger spots, up to 10 to 15 mm diameter. Eventually, spots were surrounded by a yellow halo. Particularly, affected tissues rotted quickly under high moisture. Disease severity was greatest at 75 to 90% RH and air temperature between 23 and 30°C, where affected tissues rotted quickly. This disease resulted in severe production losses. On one farm in particular, three different fields totaling 2 ha, 5 to 13% of the plants were affected. Diseased tissue was excised, immersed in a solution containing 1% sodium hypochlorite for 60 s, rinsed in water, then placed on potato dextrose agar (PDA) medium, containing 25 mg/liter of streptomycin sulphate. After 5 days, a fungus developed producing a whitish-orange mycelium when incubated under 12 h/day of fluorescent light at 23°C. The isolates obtained were purified on PDA. On this medium, they produced hyaline elliptical and ovoid conidia, rarely septate, measuring 5.0 to 9.0 × 1.7 to 3.9 (average 6.0 × 2.9) μm. Conidia were born on phialides, single, clavate, and 2.8 × 1.4 μm. Such characteristics are typical of Plectosphaerella sp. (1,2). The internal transcribed spacer (ITS) region of rDNA was amplified using the primers ITS1/ITS4 (3) and sequenced. BLAST analysis of the 530-bp segment obtained from C. endivia var. crispum isolate PLC28 and of the 527-bp from C. endivia var. latifolium isolate PLC 30, respectively, showed 99% similarity with the sequence of Plectosphaerella cucumerina (anamorph Plectosporium tabacinum), GenBank EU5945566. The nucleotide sequences of isolates PLC 28 and PLC 30 have been assigned the GenBank accession numbers KC293994 and KC293993, respectively. To confirm pathogenicity, tests were conducted on 30-day-old C. endivia plants. C. endivia var. crispum cv Myrna and C. endivia var. latifolium cv. Sardana plants, grown in 2-liter pots (1 plant per pot, 10 plants per treatment) were inoculated by spraying a 106 CFU/ml conidial suspension of the two isolates of P. cucumerina, prepared from 10-day-old cultures, grown on PDA. Inoculated plants were maintained in a growth chamber at 25 ± 1°C and 90% RH for 5 days. Non-inoculated plants, only sprayed with water, served as controls. All plants inoculated with the two isolates, showed typical leaf spots 7 days after the artificial inoculation, similar to those observed in the field. Later, spots enlarged and leaves rotted. Non-inoculated plants remained healthy. P. cucumerina was reisolated from inoculated plants. The pathogenicity tests were conducted twice with identical results. This is, to our knowledge, the first report of P. cucumerina on endive n Italy, as well as worldwide. Due to the importance of the crop in Italy, this disease can cause serious economic losses. References: (1) A. Carlucci et al. Persoonia 28:34, 2012. (2) M. E. Palm et al. Mycologia 87:397, 1995. (3) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, 1990.

scholarly journals First Report of Web Blight on Verbena Caused by Rhizoctonia solani

Plant Disease ◽  
2000 ◽  
Vol 84 (4) ◽  
pp. 492-492 ◽  
Author(s):  
G. E. Holcomb ◽  
D. E. Carling
Keyword(s):  
Rhizoctonia Solani ◽  
Fungal Pathogen ◽  
Baton Rouge ◽  
Anastomosis Group ◽  
First Report ◽  
Foliage Blight ◽  
Pathogenicity Tests ◽  
Stem Lesions ◽  
Web Blight ◽  
Branch Death

Web blight was observed on verbena (Verbena × hybrida) during July 1999 in a cultivar trial planting at Burden Research Plantation in Baton Rouge, LA. Foliage blight, stem lesions, and branch death were common symptoms on 12 of 24 cultivars in the trial. Plant death occurred in cvs. Babylon Florena (one of four plants), Purple Princess (two of four plants), and Taylortown Red (two of four plants). Isolations from infected leaves and stems on acidified water agar consistently yielded a fungus with the mycelial and cultural characteristics of Rhizoctonia solani. Pathogenicity tests were carried out by placing 5-day-old fungal mycelial plugs, grown on acidified potato dextrose agar, at the base of healthy verbena stems and holding plants in a dew chamber at 26°C. After 3 days, foliage blight and stem lesions appeared on inoculated plants, and plants were moved to a greenhouse where temperatures ranged from 23 to 32°C. Seven of nine inoculated plants died after 7 days; noninoculated plants remained healthy. The fungal pathogen was reisolated from all inoculated plants. The fungus was identified as R. solani anastomosis group (AG)-1 IB based on multinucleate condition, type of sclerotia produced, and ability to anastomose with R. solani tester isolates of AG-1 IB. This is the first report of web blight on verbena.

scholarly journals First Report of Crown Rot and Stem Rot Caused by Rhizoctonia solani AG-4 on Marmalade Bush in Italy

Plant Disease ◽  
2010 ◽  
Vol 94 (4) ◽  
pp. 486-486 ◽  
Author(s):  
G. Polizzi ◽  
D. Aiello ◽  
I. Castello ◽  
V. Guarnaccia ◽  
A. Vitale
Keyword(s):  
Rhizoctonia Solani ◽  
Anastomosis Group ◽  
Crown Rot ◽  
Fluorescent Light ◽  
First Report ◽  
Brown Discoloration ◽  
The Family ◽  
Perennial Shrub ◽  
Pathogenicity Tests ◽  
Safranin O

Marmalade bush (Streptosolen jamesonii (Benth.) Miers), also known as fire bush, is an evergreen, perennial shrub in the family Solanaceae, which is native to South America (Colombia, Ecuador, and Peru). In Italy, this species is cultivated as an ornamental creeper or bush. During September 2009, a new disease was observed in a stock of ~10,000 pot-grown, 2-month-old plants of marmalade bush in a nursery in eastern Sicily, Italy. More than 50% of the plants exhibited symptoms of disease. Disease symptoms consisted of extensive water-soaked, dark brown lesions at the crown level that girdled entire stems and an internal brown discoloration of cortical tissue. Infected plants died within a few days. Diseased tissue was disinfested for 10 s in 1% NaOCl, rinsed with sterile water, and plated on potato dextrose agar (PDA) amended with streptomycin sulfate at 100 mg/liter. Fungal colonies were initially white, turned brown after 2 to 3 days, and produced irregularly shaped, brown sclerotia. Microscopic examination showed mycelium consistent with Rhizoctonia solani Kühn that branched at right angles, constricted at the base of the branch originating from primary hyphae, and septate near the constriction. The number of nuclei per hyphal cell was determined on cultures grown at 25°C on 2% water agar in petri plates by staining with 1% safranin O and 3% KOH solution (1) and examined at ×400. The hyphal cells were all multinucleate. Anastomosis group was determined by pairing isolates on 2% water agar in petri plates (2). Pairings were made with tester strains AG-1 IA, AG-2-2-1, AG-2-2IIIB, AG-2-2IV, AG-3, AG-4, AG-5, AG-6, and AG-11. Anastomosis was observed only with tester isolates of AG-4. Pathogenicity tests were performed by placing 1-cm2 plugs of PDA from 5-day-old mycelial cultures near the base of the stem on 25 potted, healthy, 2-month-old rooted cuttings of marmalade bush. The same number of plants treated with 1-cm2 PDA plugs served as controls. Following inoculation, all plants were maintained for 20 days at 25°C and 95% relative humidity under a 12-h fluorescent light/dark regimen. Crown and stem symptoms, identical to those observed in the nursery, developed 5 days after inoculation on all inoculated plants. Control plants remained symptomless. R. solani was consistently reisolated from symptomatic tissues and identified as previously described. To our knowledge, this is the first report of R. solani causing disease on marmalade bush. References: (1) R. J. Bandoni. Mycologia 71:873, 1979. (2) C. C. Tu and J. W. Kimbrough. Mycologia 65:941, 1973.

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