scholarly journals First Report of Rhizoctonia oryzae on Pea

Plant Disease ◽  
2002 ◽  
Vol 86 (4) ◽  
pp. 442-442 ◽  
Author(s):  
T. C. Paulitz
Keyword(s):  
Pacific Northwest ◽  
Sandy Loam ◽  
Spring Barley ◽  
Subterranean Clover ◽  
Damping Off ◽  
Root Tips ◽  
First Report ◽  
Severe Stunting ◽  
Rhizoctonia Oryzae ◽  
Oat Seeds

In May 2001, severe stunting, lateral rot, and brown discoloration of taproots were observed in a field of direct-seed (no-till) pea cv. Columbia southeast of Lewiston, ID. The field had been previously cropped with direct-seeded spring barley. Roots were washed, plated on water agar containing benomyl at 1 μ/ml and chloramphenicol at 100 μg/ml, and incubated at 22°C. Fungal colonies were identified as Rhizoctonia oryzae (teleomorph Waitea circinata Warcup & Talbot) based on hyphal and colony morphology (3) and anastamosis reaction with known tester isolates. Two isolates were grown on autoclaved oat seeds for 3 weeks to produce inoculum for pathogenicity testing. One colonized oat seed was placed below a seed of Pisum sativum ‘Little Marvel’ planted in pasteurized sandy loam soil. There were five pea seeds per 10-cm-diameter pot and three replicate pots per isolate. Both isolates caused severe damping-off and stunting. Both isolates were also tested in nonpasteurized (natural) sandy loam in 4 cm × 20 cm plastic pine seedling tubes. Eight colonized oat seeds were placed in a band 1 cm below a single pea seed planted in each tube. Tubes were watered with metalaxyl (0.1g/liter, technical grade) to inhibit Pythium. Control treatments consisted of soil amended with either autoclaved oat seeds or nothing. Two isolates of R. oryzae were tested with two pea cultivars (B160 and Marjorette), with five replicates per treatment. R. oryzae did not significantly reduce emergence but did cause necrosis and browning of root tips and reduction in lateral root formation. R. oryzae was reisolated from infected roots. To our knowledge, this is the first report of R. oryzae causing disease on a dicot in North America. In Australia, a Waitea sp. was weakly virulent to subterranean clover producing constrictions of the taproot but did not affect plant survival and growth (4). W. circinata also caused damping-off of tobacco seedlings in India (2). In the Pacific Northwest, peas are often grown in rotation with wheat and barley, and R. oryzae can be virulent on these cereal crops (1). This finding may have important implications for disease management in wheat and legumes in crop rotation systems. References: (1). M. Mazzola et al. Phytopathology 86:354, 1996. (2) C. A. Raju. Tob. Res. 19:92, 1993. (3) B. Sneh et al. Identification of Rhizoctonia Species. The American Phytopathological Society, St. Paul, MN, 1991. (4) D. H. Wong et al. Trans. Br. Mycol. Soc. 85:156, 1985.

scholarly journals Virulence of Rhizoctonia oryzae on Wheat and Barley Cultivars from the Pacific Northwest

Plant Disease ◽  
2003 ◽  
Vol 87 (1) ◽  
pp. 51-55 ◽  
Author(s):  
T. C. Paulitz ◽  
J. D. Smith ◽  
K. K. Kidwell
Keyword(s):  
Winter Wheat ◽  
Pacific Northwest ◽  
Spring Wheat ◽  
Spring Barley ◽  
Root Diameter ◽  
Natural Soil ◽  
Root Tips ◽  
Barley Cultivars ◽  
Rhizoctonia Oryzae ◽  
Waitea Circinata

Rhizoctonia oryzae (teleomorph = Waitea circinata) causes sheath spot of rice and root rot of wheat and barley. R. oryzae commonly is isolated from barley, wheat, and pea plants in eastern Washington and Idaho. Eight representative isolates were tested for virulence on spring barley (Hordeum vulgare cv. Baronesse), soft white winter wheat (Triticum aestivum cv. Madsen), and hard red spring wheat (cv. Scarlet) planted in natural soil in the greenhouse and maintained at 16°C. All isolates caused significant reduction of emergence in barley, but only seven of the eight isolates and one of the eight isolates reduced emergence of winter wheat and spring wheat, respectively. All isolates caused significant stunting and reduction in the number of seminal roots, root length, and number of root tips on wheat and barley. Some isolates also reduced the frequency of fine secondary roots, resulting in a reduction of the average root diameter. Spring barley was more susceptible to R. oryzae than winter or spring wheat. The main effects of both cultivar and isolate were significant, and there was a significant isolate-cultivar interaction. R. oryzae isolate 80042 was the most virulent on barley, whereas R. oryzae isolate 801387 was the most virulent on wheat. The two isolates from pea were intermediate in virulence on wheat and barley. When screening germ plasm for potential resistance, isolates exhibiting the maximum virulence for each host should be used.

scholarly journals First Report of a Ceratobasidium sp. Causing Root Rot on Canola in Washington State

Plant Disease ◽  
2012 ◽  
Vol 96 (4) ◽  
pp. 591-591 ◽  
Author(s):  
K. L. Schroeder ◽  
T. C. Paulitz
Keyword(s):  
Plant Height ◽  
Root Rot ◽  
Root Zone ◽  
Dry Weight ◽  
Washington State ◽  
Infested Soil ◽  
Damping Off ◽  
Root Tips ◽  
Hordeum Vulgare L ◽  
First Report

Rhizoctonia root rot occurs commonly on canola (Brassica napus L.) in Washington State. Recently, isolates of an additional pathogen were found to be involved in this disease complex. Isolates of an AG-I-like Ceratobasidium sp. were collected from roots and root zone soil in central Washington near Ritzville. Identity of selected isolates was verified by sequencing the internal transcribed spacer (ITS) region of the rDNA (GenBank Accession Nos. JQ247570, JQ247571, and JQ247572), with a 90 to 93% identity to AG-I. All isolates also amplified with AG-I-like specific primers (1). Six isolates were included in pathogenicity assays conducted in the greenhouse. There were five replicates of three plants for each treatment and the experiment was conducted twice. Pasteurized soil was infested with ground oat inoculum (1%) and placed into containers (3.8 × 21 cm). Infested soils were seeded with canola, chickpea (Cicer arietinum L.), lentil (Lens culinaris Medik.), pea (Pisum sativum L.), barley (Hordeum vulgare L.), or wheat (Triticum aestivum L.). After 3 weeks of incubation at 15°C, the plants were destructively harvested. The emergence of canola was consistently reduced in soil infested with a Ceratobasidium sp., with reductions of 0 to 23% (average 11%). There was no postemergence damping-off, a symptom commonly associated with AG-2-1 (2). Plant height and top dry weights were significantly reduced for canola seeded into infested soil. Heights of plants growing in infested soil was reduced by 25 to 53% (average 42%) and top dry weight was reduced by 37 to 81% (average 61%) compared with the noninfested control. The legume hosts tested in this study were also affected by this Ceratobasidium sp., but to a lesser extent. Compared with the noninfested controls, there was evidence of preemergence damping-off in chickpea (0 to 27%, average 13%) and pea plants were consistently stunted (5 to 23%, average 12%). Chickpea and pea plants grown in infested soil also had reduced top dry weights of 9 to 28% (average 17%) and 13 to 35% (average 21%), respectively. The roots of all infected hosts had a characteristic brown discoloration with tapered, rotted root tips (spear tips). There was no reduction in emergence or plant height of wheat and barley; there was inconsistent reduction in dry weight of these plants. To our knowledge, this is the first report of a Ceratobasidium sp. causing disease on canola in Washington State. References: (1) P. A. Okubara et al. Phytopathology 98:837, 2008. (2) T. C. Paulitz et al. Plant Dis. 90:829, 2006.

scholarly journals First Report of Summer Patch of Creeping Bentgrass Caused by Magnaporthiopsis poae in Southeastern China

Plant Disease ◽  
2021 ◽  
Author(s):  
Yuxin Zhou ◽  
Min Yin ◽  
Fei Liu
Keyword(s):  
Root Zone ◽  
Soil Surface ◽  
Creeping Bentgrass ◽  
Golf Club ◽  
Golf Courses ◽  
Root Tips ◽  
Southeastern China ◽  
Putting Greens ◽  
First Report ◽  
Oat Seeds

Creeping bentgrass (Agrostis stolonifera L.) is an important cool-season perennial turfgrass that has been widely used on golf courses across China. In July 2017, an unknown disease outbreak caused damages on seven of the 18 putting greens of creeping bentgrass at Jiuqiao golf club in Hangzhou city of Zhejiang province, day-time high temperatures were consistently above 35°C during the disease development. Symptoms appeared in tan irregular patches of 5 to 20-cm diameter, exhibiting chlorosis and foliar dieback in most part. Necrotic roots were frequently observed in diseased areas and colonized with ectotrophic hyphae under a microscope. Similar symptoms and signs were reported on creeping bentgrass caused by Magnaporthiopsis poae (Landschoot & Jackson) J. Luo & N. Zhang on golf courses in Beijing (Hu et al. 2017). Fifteen disease samples were collected from seven putting greens. Dark root tips were cut, surface sterilized in 0.6% sodium hypochlorite (NaClO) for 5 min, washed twice with sterilized water, air dried for 1 min and placed on potato dextrose agar (PDA) containing each of 50 mg L-1 ampicillin, streptomycin sulfate, and tetracycline. Plates were incubated in the dark at room temperature for 4 days, and 10 fungal isolates with similar morphology as described by Clarke and Gould (1993) were consistently recovered from the diseased root tips. DNA of two representative isolates was extracted and amplified with primers ITS 5/ITS 4 (White et al. 1990). PCR products were sequenced (deposited in GenBank as MZ895215 and MZ895216), and BLAST analysis showed 99.17% similarity to M. poae (accession number: DQ528765). Six plastic pots (15 cm height × 15 cm top diameter × 10 cm bottom diameter, three replicates for each isolate) were seeded with creeping bentgrass and placed in the greenhouse for two months of plant growth before inoculation. The pathogenic inoculum was prepared by inoculating autoclaved oat seeds with M. poae isolates, followed by two weeks of incubation at 25°C. About 25 mg M. poae-infested oat seeds were placed 10 cm below the soil surface in the root zone of creeping bentgrass. Non-infested oat seeds were inoculated on healthy creeping bentgrass as controls. Pots were placed in a growth chamber with a 12-h day/night cycle at 35/28°C and watered daily to keep high soil moisture. Disease symptoms (foliar dieback and necrotic roots) were noted 3 weeks after inoculation. M. poae was consistently recovered from the roots of inoculated turf and identified molecularly as described above, fulfilling Koch’s postulates. To our knowledge, this is the first report of summer patch on creeping bentgrass caused by M. poae in southeastern China. This research demonstrates a wider distribution of M. poae and will be an important step towards the development of management strategies for summer patch control in China.

scholarly journals First Report of Red Clover Vein Mosaic Carlavirus Naturally Infecting Lentil

Plant Disease ◽  
1998 ◽  
Vol 82 (9) ◽  
pp. 1064-1064 ◽  
Author(s):  
R. C. Larsen ◽  
J. R. Myers
Keyword(s):  
Pacific Northwest ◽  
Acyrthosiphon Pisum ◽  
Sequence Data ◽  
Natural Infection ◽  
Red Clover ◽  
Enzyme Linked Immunosorbent Assay ◽  
Chenopodium Amaranticolor ◽  
First Report ◽  
Severe Stunting ◽  
Bait Plants

Lentil (Lens culinaris Medik.) is an important legume crop grown in the dryland Pacific Northwest areas of eastern Washington and Oregon, and northern Idaho. Lentil is highly susceptible to pea enation mosaic enamovirus (PEMV) and bean leafroll luteovirus (BLRV), and infection may result in severe yield losses. Recently, lentil was also found to be infected experimentally with red clover vein mosaic carlavirus (RCVMV) (1). The virus is most commonly transmitted in the Pacific Northwest by the pea aphid (Acyrthosiphon pisum Harris) in a nonpersistent manner. In 1997, cv. Brewer lentil bait plants were planted at the Vegetable Research Farm at Oregon State University to monitor incidence of PEMV and BLRV. Many of the plants developed symptoms typical of PEMV. However, other plants exhibited severe stunting, proliferation of axillary branches, and general chlorosis or death. Bait plants were harvested in August, and 204 random samples were tested for PEMV, RCVMV, BLRV, alfalfa mosaic alfamovirus (AMV), and pea streak carlavirus (PeSV) by standard enzyme-linked immunosorbent assay (ELISA) protocols. Antiserum for RCVMV was made in the Prosser lab against an isolate from chickpea collected in Washington State (1). RCVMV was detected in 76 (34%) of the 204 samples. PEMV, AMV, BLRV, and PeSV were detected in 197 (89.5%), 23 (11.3%), 2 (0.9%), and 0 (0%) of samples, respectively. Results showed that 75/76 of the samples positive for RCVMV were also coinfected with PEMV. Plants infected with RCVMV in the greenhouse also produced mild systemic mosaic symptoms in selected hosts inoculated mechanically, including pea (Pisum sativum L.), chickpea (Cicer arietinum L.), faba bean (Vicia faba L.), and lentil. Lentil and chickpea also showed moderate to severe stunting. Chlorotic local lesions were formed on Chenopodium amaranticolor Coste & Reyn. and C. quinoa Willd. Oligonucleotide primers were designed with sequence data obtained from the Washington isolate of RCVMV (1), and identification of the virus was verified in pea and lentil by polymerase chain reaction (PCR). Primer design of RCV34V and RCV653C targeted a 619-bp fragment located in the viral coat protein gene. Plants testing positive by ELISA yielded PCR products of the expected size when visualized on agarose gels. This is the first report of natural infection of lentil by RCVMV. Reference: (1) R. C. Larsen et al. Phytopathology 87:S56, 1997.

scholarly journals First Report of Damping-Off of Wild Rice in California Caused by Pythium torulosum

Plant Disease ◽  
2006 ◽  
Vol 90 (4) ◽  
pp. 523-523 ◽  
Author(s):  
D. B. Marcum ◽  
R. M. Davis
Keyword(s):  
Wild Rice ◽  
Sandy Loam ◽  
Sequence Similarity ◽  
Primary Root ◽  
Control Treatment ◽  
Damping Off ◽  
First Report ◽  
Loam Soil ◽  
Single Field ◽  
Pythium Torulosum

During 1994, damping-off of wild rice (Zizania palustris L.) in a single field in eastern Shasta County, CA resulted in near total stand failure. Since then, the disease was observed in at least 11 other fields with varying levels of stand loss. In all cases, the affected wild rice was grown as a volunteer crop following one or more years of wild rice production. Symptoms included a dark red discoloration and necrosis of the primary root followed by seedling death. When the red discoloration was limited to secondary roots, the plants often survived. Pythium torulosum, readily recovered from symptomatic roots by isolation on PARP media, was identified by morphological structures produced on grass blades in water (homothallic with smooth-walled oogonia, plerotic oospores, monoclinous antheridia, and inflated filamentous sporangia) and a 99.2% internal transcribed spacer sequence similarity of the rDNA (1). To complete Koch's postulates, inoculum of two isolates of P. torulosum grown on moistened cornmeal/sand (2%/98% [v/v]) for 3 weeks at 25°C were combined and mixed into sterilized sandy loam soil at a rate of 30 cm3 inoculum per liter of soil. Sterilized noninfested soil was used as a control treatment. Twenty wild rice seeds (cv. Franklin) were sown in each of four replicate 20-cm-diameter pots in each treatment. Plants were submerged in water and maintained in a greenhouse at 18 to 25°C. After 8 weeks, plants stands were reduced 50% in infested pots; dry weights of infected plants were reduced by 45% relative to the controls. The fungus was reisolated from symptomatic plants but not from the plants grown in noninfested soil. The experiment was repeated with similar results. To our knowledge, this is the first report of damping-off of wild rice caused by P. torulosum. Reference: (1) C. A. Levesque and W. A. M. DeCock. Mycol. Res. 108:1363, 2004.

scholarly journals First Report of Pythium schmitthenneri Causing Maize Seedling Blight in Iowa

Plant Disease ◽  
2014 ◽  
Vol 98 (7) ◽  
pp. 994-994
Author(s):  
R. L. Matthiesen ◽  
A. A. Ahmad ◽  
M. L. Ellis ◽  
A. E. Robertson
Keyword(s):  
Morphological Characteristics ◽  
Its Region ◽  
Corn Meal ◽  
Maize Seedlings ◽  
Damping Off ◽  
Seedling Blight ◽  
Root Tips ◽  
First Report ◽  
South Central ◽  
Paper Towels

In spring 2012, maize farmers in southeast and south central Iowa reported stand losses due to pre- and post-emergence damping-off, and many of the fields had to be replanted. Symptoms of the disease included rotted seed, or brown, rotted, water-soaked mesocotyls and root tips. Maize seedlings with severe root and mesocotyl symptoms were yellow and wilted, stunted, or dead. The disease occurred approximately 2 weeks after cool, wet conditions. Symptomatic mesocotyls and roots were washed for 30 min, rinsed with sterile distilled water, and blotted dry on sterile paper towels. Isolation of the pathogen was performed by aseptically cutting 2- to 3-mm sections of tissue from the edge of a lesion, placing the segments under corn meal agar (CMA) containing pimaricin, ampicillin, rifampicin, and pentachloronitrobenzene (PARP), and incubating at 22°C in the dark. Colonies that developed were putatively identified as Pythium species based on morphological characteristics and cultural features when compared to published descriptions (2,3). Characteristics of isolate IAC12F21-3 included spherical and smooth-walled oogonia 18 to 26 μm in diameter, monoclinous or usually diclinous antheridia 10 to 22 μm long and 5 to 10 μm wide with one or occasionally two per oogonium, and plerotic oospores 15 to 25 μm in diameter. Sporangia were globose to ellipsoidal, 22 to 41 μm in diameter, and zoospores were 7 to 10 μm long. Primers ITS1 and ITS4 were used to amplify the ITS region within clade E1 of 88 isolates. The resultant amplicons were sequenced and a BLAST search in GenBank confirmed isolate IAC12F21-3 as Pythium schmitthenneri based on 100% similarity with GenBank accession numbers JF836869 and JF836870. Pathogenicity testing was conducted using seed and seedling assays (1,4). Koch's postulates was performed by sampling pieces of symptomatic mesocotyl and root tissue from the inoculated pots, placing segments under CMA + PARP, and incubating at 22°C. Symptoms were similar to those observed in the field and P. schmitthenneri was re-isolated successfully. Non-inoculated control plants showed no symptoms. This is the first report of P. schmitthenneri causing seedling blight on maize in Iowa. Previously, P. schmitthenneri was reported as a pathogen on maize in Ohio (2). References: (1) K. Broders et al. Plant Dis. 91:727, 2007. (2) M. Ellis et al. Mycologia, 104:477, 2012. (3) J. Middleton. Memoirs of the Torrey Botanical Club 20:171, 1943. (4) A. Rojas et al. Phytopathology, 102(Suppl):S5.8, 2012.

First Report of Powdery Mildew of Kalanchoe blossfeldiana caused by Sphaerotheca fuliginea (Podosphaera fuliginea) in the Pacific Northwest

2003 ◽  
Vol 4 (1) ◽  
pp. 39
Author(s):  
Dean A. Glawe ◽  
Rita Hummel ◽  
Grace Jack
Keyword(s):  
Powdery Mildew ◽  
Pacific Northwest ◽  
Sphaerotheca Fuliginea ◽  
First Report ◽  
Major Disease ◽  
The Pacific ◽  
Kalanchoe Blossfeldiana ◽  
Extension Center ◽  
Kalanchoë Blossfeldiana

Kalanchoe blossfeldiana Poelln. is a common ornamental houseplant. Although powdery mildew is a major disease of this species, there are no published reports of it in the Pacific Northwest. In August, 2002, powdery mildew was observed on six indoor K. blossfeldiana plants in an office and adjacent laboratory at the Puyallup Research and Extension Center. Accepted for publication 25 March 2003. Published 17 April 2003.

First Report of Powdery Mildew of Lycium chinense (Chinese Matrimony Vine) Caused by Arthrocladiella mougeotii in the Pacific Northwest

2004 ◽  
Vol 5 (1) ◽  
pp. 16
Author(s):  
Dean A. Glawe
Keyword(s):  
North America ◽  
Powdery Mildew ◽  
Medicinal Plant ◽  
Pacific Northwest ◽  
Morphological Features ◽  
Lycium Chinense ◽  
First Report ◽  
Landscape Plant ◽  
The Pacific ◽  
Plant Grown

Chinese matrimony-vine (Lycium chinense Mill.) is a traditional medicinal plant grown in China and used as a perennial landscape plant in North America. This report documents the presence of powdery mildew on L. chinense in the Pacific Northwest and describes and illustrates morphological features of the causal agent. It appears to be the first report of a powdery mildew caused by Arthrocladiella in the Pacific Northwest. Accepted for publication 10 November 2004. Published 8 December 2004.

scholarly journals First Report of Damping-Off Caused by Rhizoctonia solani AG-4 on Mediterranean Fan Palm in Italy

Plant Disease ◽  
2010 ◽  
Vol 94 (1) ◽  
pp. 125-125 ◽  
Author(s):  
G. Polizzi ◽  
D. Aiello ◽  
I. Castello ◽  
V. Guarnaccia ◽  
A. Vitale
Keyword(s):  
Rhizoctonia Solani ◽  
Disease Incidence ◽  
Morphological Characteristics ◽  
Mediterranean Area ◽  
Western Mediterranean ◽  
Fluorescent Light ◽  
Damping Off ◽  
Centraalbureau Voor ◽  
First Report ◽  
Stem Lesions

Mediterranean fan palm (Chamaerops humilis L.), one of just two autochthonous European palms, is native to the western Mediterranean Region in southwestern Europe and northwestern Africa. It can be found growing wild in the Mediterranean area. In Europe, this species is very popular as an ornamental plant. In March 2009, a widespread damping-off was observed in a stock of approximately 30,000 potted 1-month-old plants of C. humilis cv. Vulcano in a nursery in eastern Sicily. Disease incidence was approximately 20%. Disease symptoms consisted of lesions at the seedling shoot (plumule). Stem lesions were initially orange, turned brown, and followed by death of the entire plumule or eophyll. A fungus with mycelial and morphological characteristics of Rhizoctonia solani Kühn was consistently isolated from lesions 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 and a slight constriction at the branch base. Hyphal cells removed from 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 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 on 2% water agar in petri plates (3). Anastomosis was observed only with tester isolates of AG-4, giving both C2 and C3 reactions (2). One representative isolate obtained from symptomatic tissues was deposited at the Fungal Biodiversity Centre, Centraalbureau voor Schimmelcultures (CBS No. 125095). Pathogenicity tests were performed on container-grown, healthy, 1-month-old seedlings. Twenty plants of C. humilis cv. Vulcano were inoculated near the base of the stem with two 1-cm2 PDA plugs from 5-day-old mycelial cultures. The same number of plants served as uninoculated controls. Plants were incubated in a growth chamber and maintained at 25°C and 95% relative humidity on a 12-h fluorescent light/dark regimen. Symptoms identical to those observed in the nursery appeared 5 days after inoculation and all plants died within 20 days. No disease was observed on control plants. A fungus identical in culture morphology to R. solani AG-4 was consistently reisolated from symptomatic tissues, confirming its pathogenicity. To our knowledge, this is the first report in the world of R. solani causing damping-off on Mediterranean fan palm. References: (1) R. J. Bandoni. Mycologia 71:873, 1979. (2) D. E. Carling. Page 37 in: Grouping in Rhizoctonia solani by Hyphal Anastomosis Reactions. Kluwer Academic Publishers, the Netherlands, 1996. (3) C. C. Tu and J. W. Kimbrough. Mycologia 65:941, 1973.

Sign in / Sign up

Export Citation Format

Share Document