• The Plant Pathology Journal
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• v.26 no.4
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• pp.367-371
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• 2010

In this study, we evaluated the efficacy of fluopicolide to inhibit Phytophthora capsici in vitro, and to control pepper Phytophthora blight in a greenhouse and pepper fields. Fluopicolide was tested on various developmental stages of P. capsici 06-143 (a sensitive isolate to metalaxyl) and JHAW1-2 (a resistant isolate to metalaxyl). Mycelial growth and zoosporangium germination of both isolates were completely inhibited at $4.0\;{\mu}g/ml$ of the fungicide in vitro. The $EC_{50}$ (effective concentrations reducing 50%) of P. capsici 06-143 against zoospore were $0.219\;{\mu}g/ml$, while those of JHAW1-2 were $3.829\;{\mu}g/ml$. When fluopicolide was applied at 100 and $1,000\;{\mu}g/ml$ 7 days before inoculation with P. capsici 06-143 in the greenhouse test, the disease was controlled completely until 6 days after inoculation. However, the curative effect of fluopicolide was not as much as the protective effect. When fluopicolide was applied by both soil drenching and foliar spraying, the treatments strongly protected pepper against the Phytophthora blight disease. Based on these results, fluopicolide can be a promising candidate for a fungicide to control P. capsici in the pepper fields.

• Journal of Bio-Environment Control
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• v.22 no.1
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• pp.35-41
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• 2013

This study was conducted to provide data necessary for reducing the condensation on greenhouse covering in winter season. The variation of VPD (Vapor Pressure Deficit) and condensation flux was analyzed in experimental tomato greenhouse. VPD values in experimental plastic greenhouse were greater than 0.2 kPa of disease prevention threshold, and lower than 0.5 kPa of threshold for dehumidification. The surface temperature of inside covering was slightly higher than the average temperature of outside and above curtain, and changed according to outside temperature. The humidity above curtain was nearly 100% and good condition for condensation. The humidity below curtain was 75~90% and comparatively stable condition for growing. The condensation flux value in experimental greenhouse corresponded with result of Seginer and Kantz (1986).

• Horticultural Science & Technology
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• v.19 no.1
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• pp.54-59
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• 2001

The objective of this research was to develop a screening system for selection of grape downy mildew (Plasmopara viticola)-resistant grape cultivars or seedlings under greenhouse condition. Inoculum concentrations ranging from $10^4$ to $10^5spores/mL$ for screening of resistance were evaluated and $5{\times}10^4spores/mL$ was optimum. Of the tested 14 grape cultivars, Campbell Early and Niagara were resistant to grape downy mildew, Sheridan and Cheongsoo were moderate resistant, while Kaiji, Red Queen and Ruby Okuyama were susceptible under both greenhouse and field conditions. Vitis vinifera grape cultivars were more susceptible to grape downy mildew than V. vinifera-labrusca hybrids and V. vinifera-labrusca-aestivalis hybrids. In V. vinifera-labrusca hybrids, tetraploid grape cultivars were more susceptible than diploid culivars. The evaluated results of grape downy mildew resistance under greenhouse condition were in accordance with those of field condition. Results of this study indicated that both greenhouse and field procedures could be used to screen grape cultivars and seedlings for downy mildew resistance.

• Mycobiology
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• v.42 no.1
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• pp.66-72
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• 2014

Roselle (Hibiscus sabdariffa L.) family Malvaceae is an important crop used in food, cosmetics and pharmaceutics industries. Roselle is cultivated mainly in Upper Egypt (Qena and Aswan governorates) producing 94% of total production. Root rot disease of roselle is one of the most important diseases that attack both seedlings and adult plants causing serious losses in crop productivity and quality. The main objective of the present study is to identify and characterize pathogens associated with root rot and wilt symptoms of roselle in Qena, Upper Egypt and evaluate their pathogenicity under greenhouse and field condition. Fusarium oxysporum, Macrophomina phaseolina, Fusarium solani, Fusarium equiseti and Fusarium semitectum were isolated from the natural root rot diseases in roselle. All isolated fungi were morphologically characterized and varied in their pathogenic potentialities. They could attack roselle plants causing damping-off and root rot/wilt diseases in different pathogenicity tests. The highest pathogenicity was caused by F. oxysporum and M. phaseolina followed by F. solani. The least pathogenic fungi were F. equiseti followed by F. semitectum. It obviously noted that Baladi roselle cultivar was more susceptible to infection with all tested fungi than Sobhia 17 under greenhouse and field conditions. This is the first report of fungal pathogens causing root rot and vascular wilt in roselle in Upper Egypt.

• Mycobiology
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• v.38 no.1
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• pp.39-45
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• 2010

White rot, which is caused by Sclerotium cepivorum, is a lethal disease affecting green onions. Three different types of nanosilver liquid (WA-CV-WA13B, WA-AT-WB13R, and WA-PR-WB13R) were tested in several different concentrations on three types of media to assess their antifungal activities. Results from in vitro experiments showed that all three of the nano-silver liquids had more than 90% inhibition rates at a concentration of 7 ppm. Greenhouse experiments revealed that all of the nano-silver liquids increased biomass and dry weights, and there were minimal changes in the population of various bacteria and fungi from the soil of greenhouse-cultivated green onions. In addition, a soil chemical analysis showed that there were minimal changes in soil composition.

• Korean Journal Plant Pathology
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• v.11 no.4
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• pp.344-347
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• 1995

Factors affecting on the ascospore release of Mycosphaerella nawae, the causal organism of persimmon leaf casting disease, were investigated. The ascospore release of the pathogen occurred following the precipitation of rain. The ascospore release started from the beginning of raining, reached maximum at 2 hours after the precipitation of rain, and then decreased abruptly. When the inoculum source (a file of infected leaves) was submerged in water to imitate raining conditions, 92.5% of the total ascospores were released within 1 hour after submerging, 5.8% were after 2 hours, 1.4% were after 4 hours, 0.1% were after 8 hours, and none detected after 10 hours. The inoculum source overwintered in the field released ascospores much more and earlier than the inoculum source kept in the greenhouse. The first ascospore release was about 10 days earlier, and the amount of the total liberated spores was 3∼4 times higher in the field inoculum source than the greenhouse nioculum source. The early defoliated leaves (in early October) in the previous year produced ascospores twice more than the late defoliated leaves (in early November) produced.

• The Plant Pathology Journal
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• v.21 no.3
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• pp.270-274
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• 2005

The aim of this study was to determine the effect of milk as one of the environmental friendly materials that substitute chemical fungicides for control powdery mildew (Sphaerotheca aphanis) of strawberries $(Fragaria{\times}ananassa\;Duch.)$. 'Maehyang' and 'Akihime' varieties planted in greenhouses were evaluated for the control of powdery mildew. Applications of $5\%,\;10\%\;and\;20\%$ milk had much better effects on controlling powdery mildew. In particular, $10\%$ milk showed a higher efficacy than other concentrations applied onto straw­berry in greenhouse experiments. Foliar spray application of $10\%$ milk was effective for powdery mildew, whereas drench application was not. Also, foliar spray of $10\%$ milk was able to accelerate more firmness and calcium contents of strawberry fruits than the non-treated. The $10\%$ milk applied with fertilizer salts $(Ca(H_2PO_4)_2-H_2O\;and KH_2PO_4)$ showed there was a similar efficacy to $10\%$ milk alone in greenhouse experiments. White crystals and cracks on strawberry fruits appeared by $20\%$ milk. This result indicated that $10\%$ milk was a useful substitute for fungicides to control powdery mildew of strawberry.

• The Plant Pathology Journal
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• v.27 no.2
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• pp.156-163
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• 2011

Antifungal activity of three Myxococcus spp., KYC 1126, 1136, and 2001, was tested in vitro against three phytopathogenic fungi (Botrytis cinerea, Colletotrichum acutatum, and Pyricularia grisea). Spore germination and mycelial growth of the three pathogenic fungi were completely inhibited by bioactive substances from a myxobacterium KYC 1126. In addition, the activity of KYC 1126 was fungicidal, but liquid culture filtrate of KYC 1126 did not affect protoplast reversion in C. acutatum. A bioassay of KYC 1126 filtrate against anthracnose in hot pepper was conducted in the greenhouse and field at 2009 and 2010. The incidence of anthracnose in control seedlings was 74%, but was reduced to 29% after KYC 1126 treatment. The control value with KYC 1126 was 60% while that with the fungicide dithianon was 42%. In the greenhouse, disease incidence with KYC 1126 was consistentely 10-35% lower than with fungicide as a positive control. The control value with KYC 1126 was 13.4% and 41.0%, whereas that with the fungicide was 52.3% and 63% in 2009 and 2010, respectively. Although anti-anthracnose activity of KYC 1126 was not maintained for long time in the field, the bacteriolytic myxobacterium KYC 1126 could be a prospective biocontrol agent.

• Research in Plant Disease
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• v.8 no.1
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• pp.50-54
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• 2002

A total of 55 Colletotrichum isolates from strawberry plants with anthracnose symptoms(crown rot) were inhibited in mycelial growth on potato-dextrose agar(PDA) amended with fungicides in variable degrees depending on the chemicals used, especially showing no growth on PDA with 1 mg/m/tricyclazole. However, in the detached leaf test by treating chemicals before or after inoculation of Colletotrichum sp., tricyclazole was little effective in controlling symptom development; instead azoxystrobin, which had low in vitro inhibition of mycelial growth, inhibited strongly the symptom development. Some chemicals were tested for the control of strawberry crown rot in greenhouse using three methods, sprays soil drenching and plant dipping. No or little control effect were made by chemical spray and soil drenching, but plant dipping in chemical solution, especially azoxystrobin: reduced crown rot development by about 50% in the greenhouse suggesting that the azoxystrobin treatment may be an effective control method of the crown rot of strawberry. No differences in the control efficacy were noted according to the dipping time and chemical concentration of azoxystrobin not less than 10 min and 250 mg/m/, respectively.

• Research in Plant Disease
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• v.7 no.2
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• pp.69-79
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• 2001

Meloidogyne arenaria race 2 (59%) is widely distributed, followed by M. incognita race 1 (23%), and an unknown race of M. incognita (18 ％) in greenhouses in southern Korea. The key character to distinguish between M. arenaria and M. incognita is excretory pore in female head. When oriental melon, Cucumis melo L., grafted on Shintozoa (Cucurbit maxima x Cu. moschata) is transplanted in February in a plastic tunnel inside a greenhouse infested with M. arenaria, nematodes produced egg masses on roots at 40 days after transplanting and the soil juveniles (J2) population reach maximum in July to 3,817/100 ㎤. Juveniles are distributed relatively uniform over the 180-cm-wide row horizontally and the highest density occurs at 0-25 cm soil depth. For the control of root-knot nematodes, rice rotation, solarization, and soil addition treatments are the most effective (P=0.05); treatments reduce number of J2 over 90% and increase yield two times. Corn retation, fosthiazate, and soil drying treatment are moderately effective, while sesame and green onion rotations are not effective. The relationship between M. arenaria and yield of oriental melon is adequately described by a linear regression model. In the test with wild Cucumis genetic sources introduced from U.S.Dept. of Agriculture (USDA), one of C.heptadactylus, two of C.anguria, two of C. anguria var. longaculeatus, nine of C. metuliferus are resistant to both species of root-knot nematodes.