• The Korean Journal of Mycology
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• v.35 no.2
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• pp.121-127
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• 2007

308 isolates of Ampelomyces sp. were isolated from powdery mildew fungi of 73 plant species in Korea for selection of biocontrol agents. An isolate 94013 isolated from powdery mildew fungus of red bean was selected as an effective biological control agent against cucumber powdery mildew in greenhouse. The morphological characteristics of the isolate is as follows. Pycnidia were sub-globose or elongated to pyriform, pale to dart brown, $52.5{\sim}82.5\;{\times}\;35.0{\sim}47.5\;(ave.\;62.5{\times}40.5){\mu}m$, and conidia were guttulate, straight cylindrical to fusiform, pale brown, $5.0{\sim}8.0\;{\times}\;2.5{\sim}4.3\;(ave.\;6.0{\times}3.0){\mu}m$. The isolate 94013 was identified as Ampelomyces quisqualis by morphological characteristics and rDNA ITS sequencing. The isolate A. quisqualis 94013 was different from that of the commercial product $AQ10^R$ in the rDNA ITS sequence.

• Korean Journal of Environmental Agriculture
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• v.22 no.4
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• pp.255-260
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• 2003

Silicon is known to accumulate in plants and results in greater resistance to diseases and insect pests. In this study, we investigated the effect of silicate fertilizer applied in soil on the development of powdery mildew of oriental melon. Oriental melon seedlings of four-leaf stage were transplanted and grown in a plastic film house. Silicate fertilizer was applied to maintain soil available $SiO_2$ level of 200 mg/kg one week before transplanting. Fungicide triflumizol was sprayed three times; one, two, and three weeks after transplanting. Sphaerotheca fuliginea was inoculated 2 weeks after transplanting. The number of infected leaf and the number of fungal colony in leaves were measured one, two, and three weeks after the inoculation. Three weeks after the fungal inoculation, in the treatment of fungicide triflumizol. infected leaf numbers and number of colony per leaf were reduced by 10 and 58%, respectively. In the silicate fertilizer treatment, infected leaf numbers and numbers of colony per infected leaf were suppressed only by 6 and 16%, respectively, and the efficacy was lower than that of the fungicide triflumizol. The combined treatment of silicate fertilizer and the fungicide suppressed powdery mildew more effectively, and infected leaf numbers and numbers of colony per leaf were reduced by 31 and 80%, respectively. These results indicate that although silicate fertilizer itself is not much effective in the suppression of powdery mildew, it can significantly enhance the efficacy of the fungicide.

• The Korean Journal of Pesticide Science
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• v.5 no.2
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• pp.51-57
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• 2001

Controlling effect of several surfactants on barley powdery mildew (pathogen : Erysiphae graminis) and those influence on fungicidal activity by tank-mixing with commercialized fungicides were investigated in greenhouse test with barley seedlings. While protective activity of PNPP showed 90% at $1,000{\mu}g/mL$, that of LN 13.0 91.2%, tile best among 8 surfactants used in curative test. With $500{\mu}g/mL$, LN 13.0 showed 4% of disease percentage on the first leaf of narley continuously 4 days after the curative application. Excent for PNPP, the other surfactants, including NP 13.0, LN 13.0, and PAS, showed good inhibitory activity against spore germination in water agar medium amended with those surfactants. PAS, which showed very poor effect against barley powdery mildew in greenhouse test, strongly inhibited spore germination. Fungicide of triadimefon and triforine showed no controlling activity against Erysiphae graminis in narley seedlings, but they highly controlled powdery mildew in case of addition with $500{\mu}g/mL$ of LN 13.0 and Tween 20. SP 13.0, NP 13.0, LN 13.0 and DBC showed severe phytotoxicity in first leaf of barley seedlings, but Tween 20, SLIS, PAS, and PNPP not at $1,000{\mu}g/mL$.

• Research in Plant Disease
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• v.28 no.2
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• pp.61-68
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• 2022

Powdery mildew and two-spotted spider mite are detrimental to strawberry plants and are controlled with traditional pesticides. To accommodate consumer demand, eco-friendly methods of pest control are required. Strawberries were cultivated (in soil and in a hydroponic system) for two years, and ultraviolet B (UV-B) irradiation was used as an alternative pest control during the harvesting season. Three varieties were grown (Seolhyang, Kingsberry, and Durihyang), and four UV-B lamp/mulch (black, green, and light reflection sheet [LRS]) combinations were used during harvesting: UV-B+black or green mulch, UV-B+black or green+LRS, no UV-B+black or green, and no UV-B+black or green+LRS. In all varieties, powdery mildew was 65% more controlled when UV-B irradiation was used. The adult two-spotted spider mite density was lowest in the UV-B lamp+black or green+LRS treatments. Therefore, UV-B irradiation during the strawberry harvesting season could effectively control powdery mildew and two-spotted spider mite with little side effect on the plants.

• The Plant Pathology Journal
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• v.25 no.3
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• pp.280-285
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• 2009

Powdery and downy mildews caused by Sphaerotheca fusca and Pseudoperonospora cubensis are the most common and serious diseases of cucumber worldwide. In spite of the introduction of highly effective systemic fungicides, control of these diseases remains elusive. Hence, this study aimed to develop an alternative method to chemicals in controlling the diseases by using different types of cooking oil. Egg yolk, which contains a natural emulsifier, lecithin, was selected as a surfactant to emulsify the oils. Among the different cooking oils used, soybean, canola (rape seed), safflower, sunflower, olive, and corn oils showed over 95% control values against powdery mildew of cucumber in a greenhouse test. In particular, 0.3% canola oil emulsified with 0.08% yolk (1 yolk and 60 ml canola in 20 l spray) was found to be the most effective. The treatment resulted in 98.9% and 96.3% control efficacies on powdery and downy mildews, respectively, of cucumber in the field. Canola oil exhibited direct and systemic effect, wherein powdery mildew of cucumber was suppressed only on treated leaves but not on non-treated leaves in a plant, while mycelia and conidia of the pathogen were severely distorted or destroyed by the treatment. The prospect of using the canola oil and yolk mixture as a natural fungicide is highly promising because of its effectiveness, availability, low cost, simple preparation, and safety to humans and the environment. The use of the canola oil and yolk mixture is expected to be an effective fungicide for use in organic farming and home gardening.

• Research in Plant Disease
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• v.8 no.3
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• pp.171-174
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• 2002

Powdery mildew of eggp1ant was found in Yeoiu, Korea in autumn 2000. Many white and Powdery mycelial colonies appeared on leaves, petioles and branches of the plants. Conidia with fibrosin bodies were ellipsoid to elongate-ellipsoid, 25~40$\times$15~22 ${\mu}{\textrm}{m}$ in size and formed in chains with crenate edge. Conidiophores were erect on superfical mycelium, 47~100 ${\mu}{\textrm}{m}$ in length. Germ tubes from conidia were simple and unbranched. No cleistoth-ecia were observed. On the basis of morphological characters of the conidial stage, the fungus was identified as Sphaerotheca fusca.

• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.435-439
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• 2013

Bacillus amyloliquefaciens M27 was selected as a control agent for the biological control of cucumber powdery mildew. The new mixture of B.amyloliquefaciens M27 and plant (Eucalytus) extract was developed to improve the control activity of B.amyloliquefaciens M27 against cucumber powdery mildew. The mixed formulation showed the high preventive and curative control effect against cucumber powdery mildew when it was diluted at 500 times and foliar-sprayed. Its control effect was higher in preventive spraying than curative spraying. When 500-fold diluted solution of the formulation was sprayed preventively four times at five-day intervals, three times at seven-day intervals and twice at ten-day intervals, the diseased leaf area was shown to be 4.4%, 8.0%, 27.9%, respectively; Whereas the diseased leaf area in the control plot was 45.4%. When the 500-fold diluted formulation was sprayed curatively four times at five-day intervals, three times at seven-day intervals and twice at ten-day intervals after occurred cucumber powdery mildew, the diseases leaf area was 11.5%, 25.2%, 51.8%, respectively; whereas in the control plot, the diseases leaf area was 64.3%. When the 500-fold diluted formulation was treated four times at five-day intervals in the plastic house, its control effect was higher than that treated three times at seven-day intervals and twice at ten-day intervals. As the results, the mixed formulation of B.amyloliquefaciens M27 and plant extract could be a promising candidate of bio-fungicides for the environment-friendly control of powdery mildew of cucumber.

• Korean Journal of Environmental Agriculture
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• v.25 no.1
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• pp.85-92
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• 2006

Fungicides including keroxym-methyl (strobilurin fungicide), fenarimol and trifulmizole (DMI, boscalid (anilide) and metrafenone (benzophenone) were evaluated for preventive and curative efficacies against powdery mildew on oriental melon. The fungicides were applied preventatively at 7 days, 3 days and 3 hours before inoculation. Curative applications were made by applying fungicides three times at the interval of one week when infected leaves by powdery mildew were about 16% or 30%. Then preventative and curative efficacies were evaluated one week after inoculation and final application, respectively. Boscalid and metrafenone showed preventive efficacies of 74.3 and 68.3% against powdery mildew development respectively, when treated at 7 days before inoculation. They showed 89.4 and 87.2% efficacies when treated at 3 days before iniculation and 98.5 and 93.2% at 3 hours before inoculation respectively. However, there were no preventive efficacies in kresoxym-methyl, triflumizole and femarimol (DMI fungicides) when trebled at both 7 and 3 days before inoculation. At the preventive treatment 3 hours before inoculation, they indicated 59.0, 42.5, and 37.2% efficacies, respectively. When leaves were infected about 30% by powdery mildew, curative application of boscalid and metrafenone showed 85.9 and 74.0% of efficacies, respectively. Curative efficacies of kresoxym-methyl, tiflumizole and fernarimol were 5.5, 23.0 and 46.7% respectively. When leaves were infected about 16%, curative application of boscalid and metrafenone showed 100 and 97.5% of efficacies, respectively. However, the triflumizole and fernarimol showed relatively low curative efficacies of 30.8 and 51.6%, respectively. Microscopic observation of mycelial growth and conidia formation after detection of powdery mildew disease indicated lysis of mycelium and these lysis suppression of conidia formation showed tendency in accordance with curative efficacies of fungicides.

• The Korean Journal of Pesticide Science
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• v.18 no.4
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• pp.409-416
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• 2014

This study was conducted to reduce the using amount of chemical fungicides for the control of red-pepper powdery mildew. Effect of combined application of three microbial fungicides and six chemical fungicides for the control of red-pepper powdery mildew was examined in vitro, in pot assay and under field condition. One chemical fungicide (Azoxystrobin+Chlorothalonil) among six chemical fungicides significantly suppressed three microbial fungicides (Bacillus subtilis Y1336, Bacillus subtilis DBB1501, Bacillus subtilis QST-713) registered for the control of pepper powdery mildew in vitro. In the pot assay, two mixed application such as B. subtilis DBB1501+Trifloxystrobin, B. subtilis QST713+Trifloxystrobin among nine mixed applications of three microbial fungicides and three chemical fungicides showed the highest suppressive effect against red pepper powdery mildew. Also, suppressive effect of the mixed application of B. subtilis QST713 and Trifloxystrobin was similar to that of single application of three chemical fungicides(Myclobutanil, Trifloxystrobin, Hexaconazole). In the field test, when the microbial fungicides (B. subtilis DBB1501, B. subtilis QST713) and the chemical fungicide (Trifloxystrobin) for the control of powdery mildew of red pepper were mixed foliar sprayed four times at 7 day-intervals, the control values were in the range of 70.3% to 70.9%. On the other hand, when each of the chemical fungicide (Trifloxystrobin) was foliar sprayed four times at 7 day-intervals, the control value was 72.7%. Consequently, the mixed application of the microbial fungicides and chemical fungicides could be recommended as a one of control measures for reducing the using amount of chemical fungicides.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.30-31
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• 2003

Total 291 isolates of Ampelomyces quisqualis were obtained from 32 species of powdery mildew fungi and a selected isolate, Ampelomyces quisqualis 94013 (AQ94013) effectively hyperparasitized 6 species of Sphaerotheca and one species of Erysiphe which cause serious damage on many important crops in Korea. Moreover, AQ94013 showed antagonistic effects against 12 major fungal plant pathogens as well. Results indicated that the present isolate is not a host specific hyperparasite and has a broad spectrum of biocontrol potential. Providentially, AQ94013 revealed resistance to a number of agrochemicals so as to be applied with the chemicals reciprocally.(중략)