• The Plant Pathology Journal
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• v.15 no.2
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• pp.112-118
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• 1999

Eleven species of Pythium were isolated from leaf blight symptoms on creeping bentgrass (Agrostis palustirs Huds.), Kentucky bluegrass (Poa pratenisis L.) and zoysiagrasses (Zoysia japonica Steud., and Z. matrella (L.) Merr.) planted on golf courses in Korea. Mycelial growth on potato carrot agar medium under various temperature conditions indicated that Pythium species obtained in this study could be divided into four groups based on their responses to temperature conditions. P. vanterpoolii was found to favor low temperature conditions with the optimum temperature of $25^{\circ}$, whereas P. aphanidermatum and P. myriotylum favored relatively high temperature conditions with the optimum temperature of $35^{\circ}$. Other species including P. arrhenomanes, P. catenulatum, P. graminicola, P. oligandrum, P. rostratum, P. torulosum, and P. ultimum were the intermediate group with the optimum temperature of 25~$35^{\circ}$. P. periplocum was similar to the intermediate group but the minimum temperature for its mycelial growth was $15^{\circ}$, which was approximately $5^{\circ}$ above that for the intermediate Pythium spp.group. In the pathogenicity tests conducted in the lab using potted plants, P. aphanidermatum, P.a arrhenomanes, P. catenulatum, P. graminicola, P. myriotylum, P. periplocum, P. rostratum, P. torulosum, P. ultimum, and P. vanterpoolii were found to be pathogenic to creeping bentgrass and Kentucky bluegrass. P. aphanidermatum, P. catenulatum, and P. graminicola were frequently isolated from leaf blight symptoms of creeping bentgrass and Kentucky bluegrass in golf courses during the warm and humid periods in July-August. On the other hand, P. vanterpoolii and P. torulosum were frequently isolated during the cool and humid periods in March-May, suggesting both species might be the major causes of leaf blight occurring in the spring time. Zoysiagrass was susceptible to P. arrhenomanes and the heterothallic Pythium sp. (Ht-F), showing stem and crown rot of turf-grasses at poorly drained areas under coool and humid or rainy conditions. P. oligandrum and the heterothallic Pythium sp. (Ht-L) isolated from creeping bentgrass were avirulent to all species of turfgrasses tested in this study.

• The Korean Journal of Mycology
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• v.29 no.2
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• pp.127-130
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• 2001

A Pythium species was isolated from roots of Codonopsis pilosula showing wilt symptoms in a field at Yonchon, Kyonggido of Korea from late June to early August in 2000. The Pythium species was identified as Pythium myriotylum Drechsler based on various mycological characteristics. The isolate was strongly pathogenic when inoculated to root of C. pilosula plants in pot. The inoculated plants showed typical symptoms of root rot, resulting in reduced growth of root and consequently wilting of above ground part of plants. Pythium root rot of C. pilosula caused by P. myriotylum has not been reported previously in Korea.

• Mycobiology
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• v.47 no.3
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• pp.273-279
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• 2019

A new species, Pythium subutonaiense, isolated from aquatic environments (lake) in China is being described based on morphological characters and molecular evidence. The isolates grew at temperatures between $5^{\circ}C$ and $38^{\circ}C$, and the optimum temperature was $30^{\circ}C$, with a radial growth rate of 17.6 mm at $25^{\circ}C$ per day. It is homothallic and characterized by globose to sub-globose shaped and mostly terminal or sometimes catenulate hyphal swellings, filamentous non-inflated sporangia, and smooth oogonia with hypogynous and monoclinous antheridia that contained one plerotic oospore. In phylogenetic analysis, inferred based on the internal transcribed spacer region of the ribosomal RNA gene and mitochondrial cytochrome c oxidase subunit 1 gene, the new species formed a distinct lineage in Pythium clade B. Differences between the new species and phylogenetically related and morphologically similar species are discussed.

• Journal of Microbiology
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• v.41 no.3
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• pp.252-258
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• 2003

The carbon utilizations of Bacillus species and Pythium species were investigated by using a Biolog$^{(R)}$ microplate assay to determine if there are differences in the carbon utilizations of selected strains of these species. It may be possible to afford a competitive advantage to bacterial biological control agents by providing them with a substrate that they can readily use as a carbon source, for example, in a seed coating formulation. Microplates, identified as SFP, SFN and YT were used to identify spore-forming bacteria, nonspore-forming bacteria, and yeast, respectively. Bacterial and mycelial suspensions were adjusted to turbidities of 0.10 to 0.11 at 600 nm. One hundred microliters of each of the bacterial and mycelial suspension were inoculated into each well of each of the three types of microplates. L-arabinose, D-galactose, D-melezitose and D-melibiose of the 147 carbohydrates tested were found to be utilized only by bacteria, and not by Pythium species, by Biolog$^{(R)}$ microplate assay, and this was confirmed by traditional shake flask culture. Thus, it indicated that the Biolog$^{(R)}$ microplate assay could be readily used to search for specific carbon sources that could be utilized to increase the abilities of bacterial biological control agents to adapt to contrived environments.

• The Korean Journal of Mycology
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• v.6 no.2
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• pp.19-24
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• 1978

Four species of Pythium and two species of Sclerotium previously not recorded in Korea during 1976 and Leptosphaeria salvinii which previosly reported but reidentified. Pythium aristosporm Vantery, Pythium sp. and Pythium myriotylum Drechsler were isolated from diseased rice seedlings and from green withered rice plants and Pythium irreglare Buisman was isolated from paddy soil. Three species of Pythium except P. irregulare grew well at $40^{\circ}C$ on Potato dextrose agar and were confirmed as highly pathogenic but P. irregulare showed low pathogenicity on Yushin variety of rice. Sclerotium hydrophilum and Sclerotium oryzae-sativae appeared to be weakly pathogenic, but Leptosphaeria salvinii was confirmed as a highly pathogenic. Ordinally the two species of Sclerotium grew and produced many sclerotia on dead sheath and stems of rice. There are still some problems to clarify and reconsider in regard to the pathogenicity of the sclerotial fungi because their populations were so very high in paddy fields, but their role might be wound parasite.

• The Korean Journal of Mycology
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• v.11 no.1
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• pp.27-32
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• 1983

Five species of the genus Pythium were identified from 91 isolates which were collected from rice seedlings in machine transplanting nursery boxes and paddy fields in Korea. They included P. graminicola complex, P. monospermum complex, P. rostratum complex, and P. ultimum complex. The most frequently found species of the genus Pythium was P. graminicola complex followed by P. monospermum complex. Rice seed germinability was greatly decreased by being infested with P. graminicola complex at nursery box. P. graminicola complex was the most virulent in terms of prohibiting germinations and stunting plants in nursery boxes.

• The Korean Journal of Mycology
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• v.18 no.2
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• pp.102-108
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• 1990

In order to find out the effect of medicinal plant extracts on germination of zoosporan-gium and mycelium growth of Pythium ultimum, this study was carried out. Among 28 species in 16 families of plants tested, plant extracts from 9 species were strongly inhibitory to zoosporan-gium germination of P. ultimum. Plant extracts from 3 species were strongly inhibitory to mycellium growth of P. ultimum. Especially, Paeonia suffruticosa was strongly inhibitory. P. suffruticosa was shown a strong control effect on damping-off of sesame by P. ultimum sesame, but no effect on cucumber. Seed germination of sesame and cucumber was shown phyto-alexin by extract of Phytolacca esculenta.

• Mycobiology
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• v.32 no.1
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• pp.35-41
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• 2004

A total of 374 Pythium isolates were isolated and identified from the rhizosphere soils of maize plants grown in 100 different agricultural fields in nine provinces at El-Minia Governorate, Egypt. Five Pythium spp. of P. deliense, P. graminicola, P. irregulare, P. oligandrum and P. splendens were obtained P. deliense and P. oligandrum were predominant in all of the locations with 48.1% and 41.4% of total counts, respectively. P. graminicola, P. irregulare and P. splendens were not isolated in 4, 2 and 4 provinces out of 9 provinces with 5.3%, 3.5%, and 1.6% of isolation percentage from total counts, respectively. Number of Pythium isolates in each were 34, 31, 34, 33, 34, 96, 37, 37 and 38 out of 374, for locations of El-Edwa, Maghagha, Beni-Mazar, Matai, Samalout, El-Minia city, Abou-Querquas, Mallawi and Der Mawas, respectively. Pre- and post-emergence pathogenicity tests indicated that only P. deliense was highly pathogenic to germinating grains and seedlings of maize whereas P. oligandrum was non-pathogenic.

• Research in Plant Disease
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• v.20 no.3
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• pp.201-205
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• 2014

Damping-off, caused by Rhizoctonia solani and Pythium ultimum, is a very important plant disease and affects seeds and seedlings of many plant species worldwide. To investigate control efficacy of Serenade formulation (1.34%, SC) against Rhizoctonia and Pythium damping-off diseases, seeds of chili pepper and cucumber were sown in soils inoculated with R. solani and P. ultimum and Serenade formulation was applied by soil-drenching with 9-, 19-, and 39-fold dilutions. Control values of Serenade formulation on Rhizoctonia damping-off of chili pepper was 58% and 29% for 9- and 19-fold dilutions, respectively. In the case of cucumber Rhizoctonia damping-off, Serenade treatments showed similar control efficacy with damping-off of chili pepper. On the other hand, control efficacy of Serenade formulation on Pythium damping-off of cucumber was less than control effects on Rhizoctonia damping-off. Only Pythium damping-off of chili pepper treated with 9-fold dilution Serenade was statistically different with untreated control. This result suggest that Serenade formulation could be effectively used for controlling Rhizoctonia and Pythium damping-off diseases.

• Asian Journal of Turfgrass Science
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• v.12 no.3
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• pp.215-224
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• 1998

These experiments were conducted to compare the growth characteristics, cold and drought tolerances, disease tolerance and color of the 23 varieties of four different species of cool-season turfgrass introduced from the United States of America and Europe at Yonam College in 1995. Newport and Glade of 8 Kentucky bluegrass varieties were recorded better marks than others. Newport variety was recorded the good marks in the disease tolerance of summer seasons, uniformity, coverage and texture, but the bad marks in color, drought tolerance and rust tolerance and stay green of automn seasons. Glade variety was recorded the good marks in the disease tolerance of summer seasons, uniformity and coverage, but the bad marks in drought tolerance, texture and Pythium blight tolerance. Revel and Revel Jr of 5 tall fescue varieties were recorded better marks than others in color, shoot density, uniformity, coverage, and tolerance of Pythium and Fusarium blight disease. All of red fescue varieties died of disease for rainy season however texture was the finest of all the species in spring season. Dandy of 4 ryegrass varieties was recorded better marks than others in color, shoot density, coverage, drought tolerance and tolerance of Pythium and Fusarium blight disease but texture.