scholarly journals First Report of Hypocotyl and Root Rot Disease Caused by Pythium deliense on Soybean Sprouts in Korea

Plant Disease ◽  
2003 ◽  
Vol 87 (11) ◽  
pp. 1399-1399 ◽  
Author(s):  
S.-C. Yun ◽  
J.-W. Kim
Keyword(s):  
Root Rot ◽  
Production Systems ◽  
Brown Rot ◽  
Centraalbureau Voor ◽  
First Report ◽  
Root Rot Disease ◽  
Soybean Sprouts ◽  
Pathogenicity Tests ◽  
Genus Pythium ◽  
Rot Disease

Soybean (Glycine max Merr.) sprouts have been a traditional Korean food for at least 1,000 years. During the summers of 2000 and 2001, severe hypocotyl and root rot occurred on fully grown soybean sprouts, especially in commercial recirculating mass production systems. Brown rot on water-soaked hypocotyls and roots of soybean sprouts caused a 10 to 20% loss in production yield. To investigate the cause, 180 sections of tissue were surface sterilized for 30 s in 75% ethanol and plated on potato dextrose agar (PDA). A fungus with white, aerial mycelia and cultural characteristics of Pythium sp. was isolated consistently. The fungal isolates were identified as Pythium deliense Meurs based on various mycological characteristics (2) on corn meal agar (CMA) and sucrose-asparagine bentgrass leaf culture medium (1). P. deliense oogonia were spherical, smooth, 19 to 23 μm in diameter, and their stalks bent toward the antheridia. The antheridia were the shape of a straw hat, curved club-shaped, terminal or intercalary, monoclinous, occasionally diclinous, 12 to 15 × 8 to 11 μm, and 1 per oogonium (2). In pathogenicity tests, soybean sprouts and the fungus were cultured simultaneously in containers (30 × 30 × 50 cm [W × L × H]) with a daily 3-h showering period at 25°C. There were 8,000 to 10,000 seeds per container inoculated with four plugs of agar inoculum (2 × 2 cm). Inoculum was prepared from 5-day-old fungal cultures grown on PDA. After 6 days, the inoculated soybean sprouts showed the same symptoms as described above, whereas the noninoculated sprouts remained healthy. The fungal pathogen was reisolated from all the inoculated sprouts. P. deliense has never been reported as a pathogen of soybean sprouts. To our knowledge, this is the first report of hypocotyl and root rot disease caused by Pythium deliense on soybean sprout in Korea. References: (1) J.-W. Kim and E.-W. Park. Kor. J. Mycology 25:276, 1997. (2) A. J. Van der Plaatis-Niterink. Monograph of the genus Pythium. Vol. 21, Studies in Mycology. Centraalbureau voor Schimmelcultures, Inst. R. Neth. Acad. Sci. Lett. The Netherlands, 1981.

scholarly journals First Report of Pythium Root Rot of Rau Ram (Polygonum odoratum)

Plant Disease ◽  
2005 ◽  
Vol 89 (3) ◽  
pp. 340-340
Author(s):  
E. N. Rosskopf ◽  
C. B. Yandoc ◽  
B. Stange ◽  
E. M. Lamb ◽  
D. J. Mitchell
Keyword(s):  
Root Rot ◽  
Vascular System ◽  
Pond Water ◽  
Centraalbureau Voor ◽  
First Report ◽  
Pathogenicity Tests ◽  
Symptomatic Tissue ◽  
Pythium Helicoides ◽  
Production House ◽  
Test Plants

Polygonum odoratum (= Persicaria odorata), known as rau ram or sang hum, is native to southeastern Asia and is a common herb in Vietnamese cuisine (1). It has been studied most extensively for its aromatic compound content (2). In Florida, rau ram commonly is grown hydroponically in greenhouses using large, cement beds with recirculated water. The plants form dense mats from which new growth is trimmed for market. During January of 2002, a severe dieback was observed in one production house in Saint Lucie County, FL. Plants with less severe symptoms were yellowed and stunted. Roots of symptomatic plants were largely decayed with root symptoms beginning as a tip necrosis. The cortex of severely affected roots slipped off easily, leaving a stringy vascular system. Plating of symptomatic tissue from 20 randomly selected plant samples was performed with multiple general and selective media including potato dextrose agar, corn meal agar with pimaricin, ampicillin, rifampicin, and pentachloronitrobenzene (PARP) (3). All colonies produced were identified as Pythium helicoides Drechsler on the basis of sporangial, oogonial, and antheridial characteristics (4). Isolates had proliferous, obovoid, papillate sporangia, and were homothallic with smooth-walled oogonia and thick-walled, aplerotic oospores. Multiple antheridial attachments per oogonium were common with the antheridium attached along its entire length. Pathogenicity tests were conducted using P. odoratum plants grown from commercial transplants. Two tests were performed. Each test was conducted using eight inoculated and eight control plants. In the first test, plants were maintained in 10-cm pots immersed in sterilized pond water for the duration of the test. Plants were inoculated with five 7- × 70-mm sections of freshly growing mycelial culture per plant using 10-day-old cultures of Pythium helicoides grown on water agar. Chlorosis was observed at approximately 2 months after inoculation. Root necrosis was observed in inoculated plants approximately 5 months after inoculation. This test was performed in the greenhouse with temperatures ranging from 20 to 30°C. The second test was performed in growth chambers at 35 to 40°C. Plants were maintained in 10-cm pots immersed in Hoagland's solution and were inoculated with four 6-mm plugs per plant. Symptoms were observed on inoculated plants at this temperature within 1 week of inoculation. No chlorosis or root decay was observed in noninoculated, immersed plants. The pathogen was reisolated from inoculated, symptomatic tissue. To our knowledge, this is the first report of root rot of P. odoratum caused by Pythium helicoides. References: (1) R. E. Bond. Herbarist 55:34, 1989. (2) N. X. Dung et al. J. Essent. Oil Res. 7:339, 1995. (3) M. E. Kannwischer and D. J. Mitchell. Phytopathology 68:1760, 1978. (4) A. J. van der Plaats-Niterink. Monograph of the Genus Pythium. Vol. 21, Studies in Mycology. Centraalbureau voor Schimmelcutltures, Baarn, The Netherlands, 1981.

First report of Plectosphaerella plurivora causing root rot disease in Panax notoginseng in China

2020 ◽  
Vol 168 (7-8) ◽  
pp. 375-379
Author(s):  
Li Han ◽  
Xuan Zhou ◽  
Yiting Zhao ◽  
Lixia Wu ◽  
Xiangrui Ping ◽  
...  
Keyword(s):  
Root Rot ◽  
Panax Notoginseng ◽  
First Report ◽  
Root Rot Disease ◽  
Rot Disease

scholarly journals First Report of Fusarium Wilt of Lettuce Caused by Fusarium oxysporum f. sp. lactucae in Arizona

Plant Disease ◽  
2003 ◽  
Vol 87 (10) ◽  
pp. 1265-1265 ◽  
Author(s):  
M. E. Matheron ◽  
S. T. Koike
Keyword(s):  
Fusarium Oxysporum ◽  
Root Rot ◽  
The United States ◽  
San Joaquin Valley ◽  
Fluorescent Light ◽  
Lettuce Seedling ◽  
Disease Symptoms ◽  
First Report ◽  
Root Rot Disease ◽  
Rot Disease

A new wilt and root rot disease was observed in 6 and 11 commercial fields of lettuce (Lactuca sativa) in western Arizona during the fall of 2001 and 2002, respectively. Distance between infested sites ranged from approximately 0.5 to 39 km. Five head lettuce cultivars as well as a red leaf lettuce cultivar were affected. Disease symptoms included yellowing and wilting of leaves, as well as stunting and plant death. The cortex of the crown and upper root of infected plants usually was decayed and reddish brown. Disease symptoms first appeared at the time of plant thinning and continued to develop up to plant maturity. Fusarium oxysporum was consistently isolated from symptomatic plant roots. Seeds of cv. Lighthouse were planted in nonsterile vermiculite within 3.0-cm-square × 7.0-cm-deep cells in a transplant tray and thinned to a single plant per cell. When the first true leaves were emerging, 10 individual seedlings were inoculated with a single-spore isolate of F. oxysporum recovered from diseased lettuce root cortex tissue. Inoculum was prepared by growing the fungus on potato dextrose agar in 100-mm-diameter × 15-mm-deep plastic petri dishes at 28°C with a 12-h photoperiod under fluorescent light. Once the fungus completely covered the agar surface, 50 ml of sterile distilled water was added to the dish, and the mycelia and conidia on the surface were scraped off the agar and suspended in the water. This fungal suspension was decanted, and a 2-ml aliquot containing 1.8 × 105 CFU was pipetted into the vermiculite near the stem of each lettuce seedling. Ten plants grown in noninfested vermiculite served as uninoculated controls. After inoculation, plants were maintained in a growth chamber at 28°C with a 12-h photoperiod under fluorescent light for 3 weeks. Symptoms of yellowing, wilt, vascular decay, and often plant death developed during the incubation period on all inoculated plants but not on control plants. Fusarium oxysporum was consistently reisolated from inoculated plants but not from uninoculated plants. The experiment was repeated and yielded the same results. A wilt and root rot disease of lettuce attributed to F. oxysporum f. sp. lactucae was first reported in Japan in 1967 (3) and subsequently in the United States (San Joaquin Valley of California) in 1993 (2), and Italy in 2002 (1). The researchers of the U.S. report did not cite the earlier work from Japan and described the pathogen as F. oxysporum f. sp. lactucum. The Arizona isolate used to demonstrate pathogenicity was of the same vegetative compatibility group as an isolate of the pathogen from lettuce in California reported in 1993. Several companies grow and harvest lettuce in Arizona and California. At the end of production and harvest in the fall, tractors, implements, and harvesting equipment are transported from the San Joaquin Valley in California to western Arizona. The similarity between the isolate of F. oxysporum f. sp. lactucae from western Arizona and the San Joaquin Valley of California suggest a possible introduction of the pathogen into Arizona from California, perhaps on soil adhering to farm equipment. To our knowledge, this is the first report of F. oxysporum f. sp. lactucae infecting lettuce in Arizona. References: (1) A. Garibaldi et al. Plant Dis. 86:1052, 2002. (2) J. C. Hubbard and J. S. Gerik. Plant Dis. 77:750, 1993. (3) T. Matuo and S. Motohashi. Trans. Mycol. Soc. Jpn. 8:13, 1967.

scholarly journals First Report of Fusarium commune Causing Root Rot Disease of Sugarcane (var. Badila) in China

Plant Disease ◽  
2018 ◽  
Vol 102 (8) ◽  
pp. 1660 ◽  
Author(s):  
J. Wang ◽  
Z. Chai ◽  
Y. Bao ◽  
H. Wang ◽  
Y. Li ◽  
...  
Keyword(s):  
Root Rot ◽  
First Report ◽  
Root Rot Disease ◽  
Rot Disease

scholarly journals First Report of Root Rot Disease Caused by Fusarium proliferatum on Alfalfa in China

Plant Disease ◽  
2016 ◽  
Vol 100 (12) ◽  
pp. 2526-2526 ◽  
Author(s):  
L. L. Cong ◽  
Y. Sun ◽  
J. M. Kang ◽  
M. N. Li ◽  
R. C. Long ◽  
...  
Keyword(s):  
Root Rot ◽  
Fusarium Proliferatum ◽  
First Report ◽  
Root Rot Disease ◽  
Rot Disease

scholarly journals First Report of Root Rot Disease Caused by Fusarium tricinctum on Alfalfa in North China

Plant Disease ◽  
2016 ◽  
Vol 100 (7) ◽  
pp. 1503 ◽  
Author(s):  
L. L. Cong ◽  
M. N. Li ◽  
Y. Sun ◽  
L. L. Cong ◽  
Q. C. Yang ◽  
...  
Keyword(s):  
Root Rot ◽  
North China ◽  
First Report ◽  
Root Rot Disease ◽  
Rot Disease ◽  
Fusarium Tricinctum

scholarly journals First Report of Root Rot on Rhodiola sachalinensis Caused by Fusarium verticillioides (Gibberella fujikuroi) in China

Plant Disease ◽  
2011 ◽  
Vol 95 (2) ◽  
pp. 222-222
Author(s):  
J. F. Liu ◽  
Y. Q. Cheng
Keyword(s):  
Root Rot ◽  
Tap Water ◽  
Fusarium Verticillioides ◽  
Gibberella Fujikuroi ◽  
Herbaceous Plant ◽  
Conidial Suspension ◽  
First Report ◽  
Rhodiola Sachalinensis ◽  
Root Rot Disease ◽  
Rot Disease

Rhodiola sachalinensis (family Crassulaceae), a perennial herbaceous plant with adaptogenic properties, cardiopulmonary protective effects, and central nervous system activities, is widely used as a traditional Chinese medicine (3). R. sachalinensis naturally exists only above 1,500 m elevation in the mountain area of Changbai Mountain (average July temperature ≤10°C), China. Introduction and cultivation of R. sachalinensis has been carried out in several low-altitude districts of northeast China. From 2007 to 2010, severe root rot disease was observed on R. sachalinensis in Siping districts, Jilin, China. Approximately 75 to 95% of the fields were affected with root rot disease incidence ranging from 85 to 100% under conditions of high temperatures (24 to 30°C) and high humidity. As the disease progressed, brown lesions expanded on lateral and main roots, and aboveground tissues shriveled and died. Over the 4- to 5-year period from culture to harvest, root rot became more serious. Symptomatic plants were collected from Siping districts. Samples were rinsed in tap water, necrotic areas were excised and cut into 2-mm pieces, surface sterilized with 5% NaOCl for 30 s, and rinsed in four successive changes of sterile distilled water. A single fungus was isolated on potato dextrose agar (PDA). The fungus was white, then pink and cottony, with nearly round margins after 8 days (27°C). Hyphae were separate and hyaline but macroconidia were sparse and occurred in a false head. Conidiogenous cells were monophialides. Microconidia in chains were abundant and mostly nonseptate, oval to clavate, and measured 8.1 to 14.5 × 2.0 to 3.4 μm. Morphological characteristics suggested the isolate was Fusarium verticillioides (Gibberella fujikuroi), which differed from the reported root rot pathogen of R. sachalinensis, F. oxysporum by forming microconidia in chains (1). The sexual stage of F. verticillioides was not observed. The internal transcribed spacer (ITS) fragments were amplified using ITS1 and ITS4 as primers and the 351-bp sequence was deposited in GenBank (Accession No. HQ025928). The ITS sequence showed 100% nucleotide sequence identity with F. verticillioides (GenBank Accession No. AY188916.1.). For pathogenicity tests, the isolate was cultured on PDA for 8 days. Inoculations were performed on 15 healthy R. sachalinensis plants by spraying a conidial suspension (2.0 × 105 microconidia ml–1) on roots wounded with a metal needle (6 wounds cm–2) (2). Ten plants were mock inoculated with water. Plants were incubated in a growth chamber (25°C, 70 to 80% relative humidity, 300 μmol·m–2·s–1 light intensity, and a 12-h photoperiod). After 15 days, defoliation and root rot symptoms were similar to the original symptoms observed under field conditions. F. verticillioides was reisolated from the roots of infected plants. Control plants remained asymptomatic. To our knowledge, this is the first report of F. verticillioides on R. sachalinensis in China. References: (1) X. Y. Li et al. J. Northeast For. Univ. 34:12, 2003. (2) M. Ma. Syahit et al. Am. J. Appl. Sci. 6:902, 2009. (3) T. F. Yan et al. Conserv. Genet. 4:213, 2003.

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