First report of Rhizoctonia zeae on turfgrass in Ontario

To determine the species of Rhizoctonia on bean and soybean plants grown in Samsun (Turkey), field surveys were performed at 104 locations during 2001 and 2002. Rhizoctonia spp. were obtained from isolations from the necrotic lesions on the hypocotyl and rhizosphere soils. Species were identified according to Ogoshi (3) on the basis of hyphal and colony morphology and anastomosis reaction with known tester isolates (provided by M. Hyakumachi, Gifu University, Japan). Fifty Rhizoctonia spp. isolates obtained from these locations were identified as Rhizoctonia zeae (teleomorph Waitea circinata var. zeae). Nine of the 27 bean isolates and 8 of the 23 soybean isolates were recovered from plant tissues. These isolates had optimum temperature (32°C) for growth. Colonies were orange when young, becoming salmon colored with age. Sclerotia formed both on the agar surface or submerged in the medium. Superficial sclerotia were more uniform and nearly spherical, mostly 0.2 to 0.5 mm in diameter, and they were first orange and then turned brown. Pathogenicity was tested with three R. zeae isolates grown on sterile oat seeds at 25°C for 10 days. Bean and soybean seedlings grown in 1-liter plastic pots containing sterile potting mix (field soil/composted manure/sand 2:2:1 [v/v]) at true-leaf stage were inoculated by placing five infested oat seeds adjacent to the roots. Sterile oat seeds were used for controls. After 3 to 4 weeks of incubation at 17 to 25°C in a glasshouse, roots of the plants were cleaned with tap water and evaluated for disease severity. Four replicate pots were used for each isolate/plant combination. All isolates produced superficial brown lesions on roots and hypocotyls similar to those observed on plants used for isolations and root growth declined. R. zeae was reisolated from the lesions on all bean and soybean plants used for the pathogenicity test. While R. zeae was previously reported from Johnsongrass roots (1) and corn kernels (2), to our knowledge, this is the first report of R. zeae isolated from bean and soybean plants and rhizosphere soils in Turkey. References: (1) E. Demirci, and C. Eken. Plant Dis. 83:200, 1999. (2) E. Demirci and S. Kordali. Plant Dis. 83:879, 1999. (3) A. Ogoshi. Rev. Plant. Prot. Res. 8:93, 1975.

Download Full-text

First report of Rhizoctonia zeae on Lolium perenne and Festuca sp. in Hungary

Plant Pathology ◽

10.1111/j.1365-3059.2005.01172.x ◽

2005 ◽

Vol 54 (2) ◽

pp. 250-250 ◽

Cited By ~ 2

Author(s):

L. Vajna ◽

G. Oros

Keyword(s):

Lolium Perenne ◽

First Report ◽

Rhizoctonia Zeae

Download Full-text

Characterization of Rhizoctonia-Like Fungi Isolated from Agronomic Crops and Turfgrasses in Mississippi

Plant Disease ◽

10.1094/pdis-91-3-0260 ◽

2007 ◽

Vol 91 (3) ◽

pp. 260-265 ◽

Cited By ~ 13

Author(s):

M. Tomaso-Peterson ◽

L. E. Trevathan

Keyword(s):

Diverse Group ◽

First Report ◽

Binucleate Rhizoctonia ◽

Anastomosis Groups ◽

Agronomic Crops ◽

Sharp Eyespot ◽

Rhizoctonia Zeae

Twenty-three isolates of Rhizoctonia spp. from agronomic crops and turfgrasses were characterized by cytological and pathological methods in order to establish the identity, pathogenicity, and virulence of Rhizoctonia spp. and anastomosis groups that occur on these hosts in Mississippi. Twelve isolates were identified as R. solani, including the five anastomosis groups (AGs) AG-1-IB, AG-2-2, AG-4, AG-5, and AG-13. Rhizoctonia zeae, R. oryzae, and eight binucleate Rhizoctonia sp., including R. cerealis, also were identified. R. solani AG-4 isolates were consistently the most virulent isolates on all hosts in pathogenicity evaluations. Pathogenicity of AG-2-2 and AG-5 isolates, binucleate Rhizoctonia spp., and R. oryzae varied between hosts. Two AG-2-2 isolates from bermudagrass or wheat were determined to be clonal isolates, with numerous self-anastomosis reactions. R. solani (AG-1-IB) was pathogenic on all graminaceous hosts. R. cerealis produced sharp eyespot symptoms on wheat and corn and minimal symptoms on cotton and soybean. This is a first report of R. cerealis as a pathogen of corn. R. zeae isolates were pathogenic on all hosts, including cotton and soybean. These results indicate that a diverse group of Rhizoctonia spp. occurs as pathogens on a wide variety of agronomic crops and turfgrasses in Mississippi.

Download Full-text

First Report of Rhizoctonia zeae in Turkey

Plant Disease ◽

10.1094/pdis.1999.83.2.200d ◽

1999 ◽

Vol 83 (2) ◽

pp. 200-200

Author(s):

E. Demirci ◽

C. Eken

Keyword(s):

Sandy Loam ◽

Vegetative State ◽

Low Frequency ◽

Pathogenic Fungi ◽

Disease Symptoms ◽

Soil Mixture ◽

First Report ◽

Waitea Circinata ◽

Rhizoctonia Zeae ◽

Control Disease

In 1997, during a study to determine the pathogenic fungi on Johnsongrass (Sorgum halepense) in the Yusufeli District of Artvin Province, 10 isolates of a Rhizoctonia sp. were obtained from necrotic roots. In anastomosis tests, Johnsongrass isolates fused at low frequency with the Rhizoctonia sp. (teleomorph: Waitea circinata var. circinata) and R. oryzae (teleomorph: W. circinata var. oryzae), and at high frequency with R. zeae (teleomorph: W. circinata var. zeae). Test isolates of the Rhizoctonia sp. (W. circinata var. circinata), R. oryzae, and R. zeae (isolate nos. W616, 231, and 590, respectively) were provided by R. H. Leiner (University of Alaska Fairbanks). In addition, Johnsongrass isolates were identified as R. zeae based on colony morphology of the vegetative state. Pathogenicity of two isolates (JR-3 and JR-8) was determined on Johnsongrass seedlings at 25°C. Six seeds were sown in a 10-cm-diameter pot containing a sterile soil mixture of coarse sandy loam and sand (1:1, vol/vol). Each pot was a replicate and each treatment was replicated four times. Four-week-old Johnsongrass seedlings were inoculated by gently removing the soil mixture from one side of the stem, placing a colonized potato dextrose agar (PDA) 4-mm-diameter plug in direct contact with the base of the stem, and covering the inoculum with the soil mixture. A sterile, uncolonized PDA plug was used as a control. Disease symptoms were observed 2 weeks after inoculation. Brownish, sunken lesions were observed on the base of stems and roots of seedlings inoculated with R. zeae. Stems and roots of uninoculated seedlings were lesion free. Isolates JR-3 and JR-8 were reisolated from plants grown in their respective treatments. This is the first report of R. zeae from Turkey.

Download Full-text

First Report of Leaf and Sheath Spot Caused by Rhizoctonia zeae Affecting Panicum tennesseense in Rhode Island

Plant Disease ◽

10.1094/pdis.2003.87.8.1006c ◽

2003 ◽

Vol 87 (8) ◽

pp. 1006-1006 ◽

Cited By ~ 1

Author(s):

N. A. Mitkowski

Keyword(s):

New England ◽

Rhode Island ◽

Uv Light ◽

Aerial Mycelium ◽

Optimal Growth ◽

Washington County ◽

First Report ◽

Humidity Chamber ◽

The Media ◽

Rhizoctonia Zeae

Panicum tennesseense Ashe is a perennial, coarse-textured, cool-season grass (similar in appearance to many warm-seasoned grasses), which grows in the southern coastal areas of New England and is commonly found in home lawns, roadsides, and meadows. In August 2002, a large stand of P. tennesseense with significant leaf spotting was identified in Washington County, RI. Lesions were excised, surface sterilized with 0.6% sodium hypochlorite, and plated on one-half-strength potato dextrose agar (PDA). Cultures were incubated at 25°C, and mycelia quickly covered plates within 3 days. After 2 weeks in darkness, plates were covered with white, aerial mycelium. When placed under near-UV light, no aerial mycelium was produced, and mycelia were a salmon color. After 5 weeks, separate, spherical, 0.5-mm-diameter beige sclerotia were produced submerged throughout the media and turned red within a few days. Sclerotia were not produced in the absence of near-UV light. Spores were not produced, and right-angled branching, characteristic of Rhizoctonia spp., was observed. Monilioid hyphae were also produced in culture. At the optimal growth temperature of 32°C, mycelia grew an average of 33.6 mm/day. Cells were stained using safranin, and the number of nuclei observed within young hyphal cells was five or seven. On the basis of the described mycelial and sclerotial characterisitics, the isolated fungus was identified as Rhizoctonia zeae (1,2). To demonstrate pathogenicity, plugs of isolated fungi were cut from PDA plates, placed on leaf blades at the junction with leaf sheaths, and incubated in a greenhouse humidity chamber at an average temperature of 32°C and 80% humidity. After 3 days, significant disease was observed and included blighting of newly emerged shoots, blighting and spotting on leaf sheaths, and severe spotting on leaf lamina. Whereas Rhizoctonia solani has been reported as a pathogen on P. tennesseense, to our knowledge, this is the first report of R. zeae induced leaf and sheath spot on this host (1). References: (1) H. Couch. Diseases of Turfgrasses. Krieger Publishing Co., Malabar, FL, 1995. (2) B. Sneh et al. Identification of Rhizoctonia species. The American Phytopathological Society, St. Paul, MN. 1991.

Download Full-text

A fossil Aspergillus from Eocene Dominican amber

Journal of Paleontology ◽

10.1017/s0022336000058996 ◽

1988 ◽

Vol 62 (01) ◽

pp. 141-143 ◽

Cited By ~ 15

Author(s):

Gerard M. Thomas ◽

George O. Poinar

Keyword(s):

Dominican Republic ◽

Fossil Species ◽

First Report ◽

Dominican Amber ◽

Eocene Amber

A sporulating Aspergillus is described from a piece of Eocene amber originating from the Dominican Republic. The Aspergillus most closely resembles a form of the white spored phase of Aspergillus janus Raper and Thom. This is the first report of a fossil species of Aspergillus.

Download Full-text