• The Plant Pathology Journal
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• v.19 no.4
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• pp.200-202
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• 2003

Leaf spots were first observed on watermelon (Citrullus vulgaris Schrad) under polyethylene film-covered green-house in November 2002. Symptoms appeared as dark-brown circles or large irregular spots on the leaves of watermelon. Occasionally, zonal growth of the lesions was observed. Under humid conditions, small black sclerotium-like bodies (sporodochia) were produced on the surface of the lesions. The sporodochia on leaf lesions were sessile, polymorphic, variable in size, 35-850 $\mu\textrm{m}$ in diameter, and 30-470 $\mu\textrm{m}$ in depth. Conidia in sporodochium were black in mass, one-celled, rod-shaped, with rounded ends, hyaline, guttulate, and measured 6-8$\times$1.6-2.2 $\mu\textrm{m}$ in size. The pathogen was identified as Myrothecium roridum Tode ex Fr. This is the first report of Myrothecium leaf spot on watermelon naturally occurring in commercial greenhouses.

• The Plant Pathology Journal
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• v.24 no.4
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• pp.453-460
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• 2008

In the course of in vitro and in vivo screening for bioherbicidal agents, a hyphomycete fungus, Myrothecium sp. F0252 was selected as a candidate for the biocontrol of weeds. The isolate was identified as Myrothecium roridum Tode ex. Fries based on the morphological characteristics and 18S ribosomal DNA sequence analysis and registered as Myrothecium roridum F0252. In order to evaluate the in vitro effect of M. roridum F0252 on germination of ladino clover and white clover (Trifolium repens L.) seeds, spore solution of the fungus was employed in two concentrations, $6.5{\times}10^6$ and $2.5{\times}10^7$ spores per mL and then inoculated to the seeds. The fungal spores inhibited the seed germination, infected the seedlings, and caused an abnormal withering and inhibition of seedling growth. In addition, when the herbicidal activity of crude ethyl acetate extract from the liquid culture was assessed on a mini-plant, duck-weed (Lemna paucicostata (L.) Hegelm.), the extract showed high inhibitory effect at the level of $12.5{\mu}g$ per mL. On the other hand, in vivo herbicidal activity of M. roridum F0252 was evaluated by a whole plant spray method. M. roridum F0252 exhibited strong and broad-spectrum herbicidal activity. The herbicidal values ranged from 95-100% against 7 weeds, including Abutilon avicennae and Xanthium strumarium, and 70-80% against Digitaria sanguinalis and Sagittaria pygmaea. When the nutritional utilization (95 carbon sources) pattern of M. roridum F0252 was investigated, it varied with water activity ($a_w$) and temperature conditions, supplying good, basic information in regard to nutritional utilization for proper cultivation and formulation. Our results showed that M. roridum F0252 might be used as a potential biocontrol agent against weedy plants.

• Mycobiology
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• v.42 no.1
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• pp.82-85
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• 2014

During an investigation of microorganisms and pests in plant culture media from imported anthurium pots, a fungal isolate (DUCC4002) was detected. Based on its morphological characters including colony shape on potato dextrose agar, the microstructures of spores observed by light and scanning electron microscopy and the results of phylogenetic analysis using an internal transcribed spacer rDNA sequence, the fungal isolate was identified as Myrothecium roridum. Pathogenicity testing on anthurium leaves revealed that the fungus could colonize and produce sporodochia on the inoculated leaves. This is the first report of M. roridum detected in imported plant culture medium in Korea.

• International Journal of Industrial Entomology and Biomaterials
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• v.12 no.1
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• pp.35-39
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• 2006

Fifty-six indigenous and twenty nine exotic mulberry varieties were screened against powdery mildew, Myrothecium leaf spot, Pseudocercospora leaf spot, sooty mold and bacterial leaf spot for a period of three years under field condition. The percent disease index (PDI) was recorded during peak season of the foliar diseases. Out of eighty-five varieties studied, ten varieties were highly resistant and eight were resistant to powdery mildew; six varieties were immune and seventy-eight varieties were highly resistant to Myrothecium leaf spot; sixty varieties were highly resistant and 21 were resistant to Pseudocercospora leaf spot; forty four varieties were highly resistant to sooty mold and two varieties were immune and fifty-eight were highly resistant to bacterial leaf spot. Lowest cumulatative disease index was observed in M. multicaulis (7.28) followed by Thailand lobed (7.85) and Italian mulberry (8.06).

• International Journal of Industrial Entomology and Biomaterials
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• v.14 no.2
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• pp.75-80
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• 2007

Ethanolic extracts of twenty-one plant species were tested in vitro for their fungitoxic properties against leaf spot causing pathogen of mulberry Myrothecium roridum by poisoned food technique. Ethanolic extracts of twenty-plant spp. reduced mycelial growth of M. roridum significantly except E. pulcherrima. Highest inhibition of M. roridum colony growth observed in 10% extracts of E. citriodora (49.45%) followed by D. metel (39.45%), Chromolaena odoratum (25.56%) and A. sativum (25.00%). Among the concentration tested, 10% concentration was found significantly higher effective on reducing colony growth followed by 5 and 2.5%. Aqueous extract fresh leaves/bulb of seven short-listed plant spp. (inhibition>15% in ethanolic extracts) revealed that D. metel inhibited (23.43%) followed by E. citriodora (14.66%), C. odoratum (13.53%). On dry leaf extracts D. metel was found more effective than E. citriodora. The results indicated that D. metel, E. citriodora, C. odoratum and A. sativum having high fungitoxicity against M. roridum and ethanolic extract found more effective than aqueous extract.

• International Journal of Industrial Entomology and Biomaterials
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• v.6 no.2
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• pp.163-169
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• 2003

Studies were conducted on the effect of pruning time, host age, conidial dispersal and weather parameters on the incidence and severity of mulberry leaf spot (Myrothecium roridum). The disease severity (%) increased with increase in shoot age irrespective of pruning date. Maximum disease severity was observed in plants pruned during first week of April and minimum disease severity in plants pruned during first week of March. Significant (P ＜ 0.01) influence of date of pruning, shoot age and their interaction was observed on severity of the disease. Apparent infection rate (r) was significantly higher during the plant growth period from day 48 to day 55. Average apparent yale was higher in plants pruned during first week of April and least in plants pruned during first week of July. The disease infection was negatively correlated to distance from the inoculum source. Leaf spot severity (%) was influenced by weather parameters. Multiple regression analysis revealed contribution of various combinations of weather parameters on the disease severity. Linear prediction model $(Y ＝ －81.803＋1.176x_2＋0.765x_3) with significant $R^2$ was developed for prediction of the disease under natural epiphytotic condition.

• Mycobiology
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• v.42 no.2
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• pp.203-205
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• 2014

In 2010, symptoms of leaf and stem rot were observed on potted plants (Peperomia quadrangularis) in a greenhouse in Yongin, Korea. The causative pathogen was identified as Myrothecium roridum based on morphological data, internal transcribed spacer sequence analysis, and pathogenicity test. To our knowledge, this is the first report of M. roridum causing leaf and stem rot disease on P. quadrangularis in Korea and elsewhere worldwide.

• International Journal of Industrial Entomology and Biomaterials
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• v.7 no.2
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• pp.175-180
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• 2003

Changes in biochemical constituents and physiological alteration were studied in various intensities (1-5%, 6-15%, 16-30%, 31-50% and ＞ 50%) of leaf spot (Myrothecium roridum) on mulberry leaves and compared with healthy leaves. Chlorophyll, total soluble sugar and total protein were decreased (P ＜ 0.01), but total phenol increased due to pathogen infection. Changes in biochemical constituents showed significant correlation with intensity of disease. Chlorophyll ($r^2$= 0.92), and protein (($r^2$= 0.83) possessed negative while phenol (($r^2$= 0.61) possessed positive correlation. Photosynthetic rate, transpiration rate, stomatal conductance, moisture content (%) and physiological water use efficiency (pWUE) were decreased, but stomatal resistance increased in the infected leaves. Physiological parameters also possessed significant (P ＜ 0.01) correlation with disease intensity. Photosynthetic rate (($r^2$= 0.96), transpiration rate ($r^2$=0.88), stomatal conductance (($r^2$= = 0.65), physiological water use efficiency (($r^2$= 0.88) and moisture content (r = 0.85) were negatively but stomatal resistance (($r^2$= 0.75) was positively correlated to disease intensities.

• The Korean Journal of Mycology
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• v.46 no.2
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• pp.134-144
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• 2018

Three fungal strains belonging to the class Sordariomycetes, namely BH-06, 17-039 and BE12-1, were isolated from soils in Korea and identified as Chaunopycnis alba, Myrothecium cinctum and Humicola olivacea, respectively. These species were confirmed according to their morphological characteristics and phylogenetic relationships determined based on internal transcribed spacer regions, as well as large subunit, small subunit, ${\beta}$-Tubulin and RNA polymerase II largest subunit sequences of ribosomal DNA. These three species are the first members of the Sordariomycetes reported in Korea.

• International Journal of Industrial Entomology and Biomaterials
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• v.5 no.2
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• pp.183-188
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• 2002

Anti-fungal potential of 5 plant extracts viz., Eucalyptus citriodora, Allium sativum, Cassia sophera, Chromolaena odorata and Datura metel on the growth of mulberry brown leaf spot pathogen Myrothecium roridum were examined. Except fur the aqueous extract of Allium bulb, ethanolic leaf extract of all other plants more efficiently reduced the colony growth of the fungus on potato-dextrose-agar, Of which, Allium and Eucalyptus extracts were more effective. Initiation of radial growth of M. roridum on solid media was deferred maximum 6 days by ethanolic Eucalyptus extract and 4 days by aqueous Allium extract at $0.4 mg.ml^{-1}$. In the liquid media amended with Eucalyptus extract ($0.4 mg.ml^{-1}$) complete inhibition of sporulation was noticed upto 8 days, and initial inhibition of mycelial bio-mass generation was considerably diminished with time and reduction was 1.3 fold 14 days after application. While, complete inhibition of mycelial growth for 6-14 days was recorded with $\geq$0.1 mg.ml$^{-1}$ commercial eucalyptus oil. However, rejuvenation of growth appeared when fungus was re-inoculated in fresh media. Post-inoculate application of different doses Of Eucalyptus and Allium extracts significantly (p < 0.05) reduced the disease severity in pot-ted mulberry. However, persistence of the effect up to 28 days was apparent at $\geq$ 1.0 mg.ml$^{-1}$ and effectively was on par with carbendazim (1 mg.ml$^{-1}$ ). Almost equal control ability of 1.0 mg.ml$^{-1}$ Eucalyptus extracts can be achieved by ca. 10 times lowered dose of commercial eucalyptus oil. It seems, the toxic principle of E. citrodora to M. roridum is fungistatic in nature and may have essential oil based origin.