• Korean Journal of Agricultural Science
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• v.46 no.1
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• pp.103-111
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• 2019

Gray mold caused by Botrytis cinerea on strawberry plants is an economically significant disease in Korea. The rates for diseased fruits are high during the strawberry harvesting period from December to February, especially in hydroponic cultivation. This study assessed the effect of the nitrogen type in the soil culture and the electrical conductivity (EC) of the nutrient solution in a hydroponic culture on the gray mold incidence in 'Seolhyang' strawberry plants. The nitrogen sources assayed included calcium nitrate tetrahydrate (CN4), calcium nitrate decahydrate (CN10), ammonium sulfate (AS), and commercial fertilizer 213 (213). The effect of the EC was tested at 0.5, 0.8, 1.0, and $1.5dS{\cdot}m^{-1}$. The occurrence of gray mold varied according to the nitrogen type. The disease incidence and nitrogen content for the main nitrogen type were higher compared to the non-treated control. The AS treatment showed the highest occurrence of tipburn and gray mold. The incidence of gray mold as well as the nitrogen and phosphorus content of the leaves increased as the EC level was increased. These results indicate that the incidence of gray mold in strawberry plants is related to the nitrogen content of the leaf and the EC of the nutrient solution.

• Research in Plant Disease
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• v.20 no.2
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• pp.129-131
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• 2014

In February 2014, gray mold rotting symptoms were observed in carrots in cold storage at Gangneung, Gangwon province, Korea. The typical symptom of gray mold rot showed abundant blackish gray mycelia and conidia was observed on the infected root. The pathogen was isolated from infected root and cultured on PDA for further fungal morphological observation and confirming its pathogenicity according to Koch's postulates. Results of morphological data, pathogenicity test and rDNA internal transcribed spacer (ITS 1 and 4) sequence showed that the postharvest gray mold rot of carrot was caused by Botyrtis cinerea. This is the first report of postharvest gray mold rot on carrot in Korea.

• Research in Plant Disease
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• v.29 no.3
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• pp.295-298
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• 2023

During a disease survey conducted in April 2022, we observed severe gray mold symptoms on inflorescences of mango trees (Mangifera indica) grown in a vinyl greenhouse in Jeju, Korea. The symptoms occurred on the flowers and peduncles, on which a lot of gray molds were formed. The incidence of gray mold on the inflorescences in the vinyl greenhouse ranged from 10% to 40%. Three fungal isolates were obtained from the lesions and identified as Botrytis cinerea based on their morphological characteristics and phylogenetic analysis. All isolates of B. cinerea were tested for their pathogenicity to inflorescences of mango trees through artificial inoculation. The pathogenicity of the isolates was confirmed on the flowers and peduncles. The symptoms induced by the isolates were similar to those on the inflorescences of mango trees observed in the disease survey. This is the first report of B. cinerea causing gray mold in mango in Korea.

• The Korean Journal of Mycology
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• v.51 no.4
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• pp.259-263
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• 2023

During crop disease surveys in 2019 and 2021, we observed gray mold symptoms on the leaves of wasabi (Eutrema japonicum) plants grown in vinyl greenhouses in Taebaek and Pyeongchang, Gangwon Province, Korea. The symptoms appeared at the edges of the leaves, where the infected areas turned black and rotted, and many gray molds formed on the lesions. The incidence of gray mold on the leaves in the vinyl greenhouses at the two locations ranged from 1 to 30%. Four fungal isolates were obtained from leaf lesions and identified as Botrytis cinerea based on morphological characteristics and phylogenetic analysis. Two isolates of B. cinerea were used for pathogenicity tests on the leaves of wasabi plants by artificial inoculation. The pathogenicity of the isolates was confirmed in leaves. The symptoms induced by the isolates were similar to those observed in wasabi leaves in the vinyl greenhouses investigated. This is the first report of B. cinerea causing gray mold in wasabi in Korea.

• Research in Plant Disease
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• v.23 no.4
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• pp.372-378
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• 2017

In this study, we identified the causative agent of post-harvest gray mold on broccoli that was stored on a farmers' cooperative in Pyeongchang, Gangwon Province, South Korea, in September 2016. The incidence of gray mold on broccoli was 10-30% after 3-5 weeks of storage at $3^{\circ}C$. Symptoms included brownish curd and gray-to-dark mycelia with abundant conidia on the infected broccoli curds. The fungus was isolated from infected fruit and cultured on potato dextrose agar. To identify the fungus, we examined the morphological characteristics and sequenced the rDNA of the fungus and confirmed its pathogenicity according to Koch's postulates. The results of the morphological examination, pathogenicity test, and sequencing of the 5.8S rDNA of the internal transcribed spacer regions (ITS1 and ITS4) and three nuclear protein-coding genes, G3PDH, HSP60, and RPB2, revealed that the causal agent of the post-harvest gray mold on broccoli was Botrytis cinerea. To our knowledge, this is the first report of post-harvest gray mold on broccoli in Korea.

• Journal of Bio-Environment Control
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• v.21 no.2
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• pp.134-139
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• 2012

Inhibition effects on spore germination and mycelia growth for gray mold (Botrytis cinerea) were investigated in vitro using environment-friendly agricultural materials as well as environment-friendly pesticides. The inhibition effect on mycelia growth of gray mold is the highest when the gray mold mycelia were treated with a pesticide (commercial name: Koreayeok, Jihabudea KM, Sootingtan, Sootingstar) that contains a mixture of Bacillus subtilis, resulting in 100% inhibition of the mycelia growth. Meanwhile, the range of less than 20% inhibition effects on the growth of gray mold mycelia was observed with other commercial agricultural materials. The significant inhibition effects on spore germination of gray mold fungus were shown in vitro with two water dispersible pesticides containing sulfur [BTB (97.7%) and SulfurStar (92.3%)], respectively. These in vitro results of inhibiting of the spore germination and mycelia growth together cannot found. It remains to be determined whether the selected environment-friendly agricultural materials in effective control of gray mold in vitro can be used to control gray mold in field.

• Korean Journal Plant Pathology
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• v.11 no.4
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• pp.348-352
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• 1995

Severe gray mold neck rot of onion occurred in most farmers' fields in the southern part of Korea, and 20∼50% of onions were infected by the disease at Goheung, Chonnam, in 1994. Symptoms of the disease appeared on the lower leaves near the soil surface in late February. The symptoms initially appeared as yellowish blotch with compact gray mold on the surface of the infected leaves and developed to blast of the aboveground parts of onions. As brown to dark brown symptoms progressed around the necks of onion later, the bulbs were rotting gradually. Botrytis sp. repeatedly isolated from the lesions produced the typical symptom on the neck of healthy onion 7 days after wound inoculation of conidial suspension of the fungus. The fungus reisolated from the bulbs was identified as Botrytis allii Munn based on the morphological and cultural characteristics and pathogenicity. This is first report of a gray mold neck rot of onion in Korea.

• The Plant Pathology Journal
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• v.19 no.2
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• pp.102-105
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• 2003

Gray mold severely occurred up to 50% in freesia and gladiolus grown in the fields and greenhouses in Korea from 1998 to 2000. Symptoms appeared as spot and blight on loaves and flowers of infected plants. A total of 25 isolates was obtained from infected plant parts. All the isolates were identified as Botrytis gladiolorum based on their morphological and cultural characteristics. Gray mold symptoms similar to those observed in the fields and greenhouses were induced on the plants of freesia and gladiolus by artificial inoculation with four isolates of the fungus. This is the first report of gray mold of freesia caused by B. gladiolorum in Korea.

• Korean Journal of Medicinal Crop Science
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• v.23 no.6
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• pp.473-479
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• 2015

Background : To control ginseng gray mold, farmers have mainly used inorganic chemical based fungicides. The recent emergence of fungicide resistance has reduced the effectiveness of such control methods. Such pesticides also carry additional problems, such as diffuse pollution. Methods and Results : Six treatments of organic agricultural materials were tested for control of ginseng gray mold, CAPW (Chrysophanic acid + Phytoncide + Wood vinegar), EmEWV (Emodin + Ethanol + Wood vinegar), CEWV (Curcumin + Eugenol + Wood vinegar), Bacillus subtilis, soybean oil and sulfur. The control effect for gray mold by a single application of the agrochemical fungicide industrial Fenhexamid wettable powder (WP) was 84.4%. The control effect by CAPW, EmEWV and CEWV varied between 52.7 - 64.9%. The control effect by B. subtilis, soybean oil, and sulfur were 32.9 - 59.2%. Conclusions : In the field tests, CAPW showed the highest control effects when used before, and at first stage of disease incidence, against ginseng gray mold.

• Journal of agriculture & life science
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• v.50 no.2
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• pp.25-32
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• 2016

A severe outbreak of gray mold on kenaf (Hibiscus cannabinus L.) was observed on kenaf grown in the research field of Gyeongsangnam-do Agricultural Research and Extension Services, Jinju, Korea in 2014. Gray mold appeared on young plants as gray-brown velvety mold covering stems and leaves. Infections that girdled the stem caused wilting above the infected area and developed a canker. The casual fungus formed grayish brown colonies on potato dextrose agar. The conidia were one celled, mostly ellipsoid or ovoid in shape, colorless or pale brown in color, and 6-18 × 4-10 ㎛ in size. The conidiophores were 15-32 ㎛ in length. These measurements and taxonomic characteristics were most similar to those of Botrytis. DNA sequencing and phylogenetic analysis of the complete internal transcribed spacer rRNA gene region confirmed that the fungal isolates were indeed Borytis cinerea. Koch's postulates were supported by pathogenicity tests conducted on healthy plants. On the basis of mycological characteristics and pathogenicity test on host plants, the fungus was identified as Botrytis cinerea. To the best of our knowledge, this is the first report of a gray mold caused by B. cinerea on kenaf in Korea.