• Journal of Microbiology and Biotechnology
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• v.17 no.12
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• pp.2071-2075
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• 2007

Fourteen Bacillus thuringiensis isolates having both insecticidal activity and in vitro antifungal activity were selected and tested for in vivo antifungal activity against tomato late blight, wheat leaf rust, tomato gray mold, and barley powdery mildew in growth chambers. All the isolates represented more than 70% disease control efficacy against at least one of four plant diseases. Specifically, 12 isolates exhibited strong control activity against barley powdery mildew. Under glasshouse conditions, four (50-02, 52-08, 52-16, and 52-18) of the isolates also displayed potent control efficacy against cucumber powdery mildew. To our knowledge, this is the first report of B. thuringiensis isolates that have disease control efficacy against powdery mildew of barley and cucumber as well as insecticidal activity.

• The Plant Pathology Journal
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• v.18 no.2
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• pp.68-73
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• 2002

The influence of fungicidal spray was assessed on powdery mildew epidemics caused by Erysiphe polygoni D.C. and on yield-attributing characters of mungbean [Vigna radiata (L.) Wilczek]. Mildew attack adversely affected the yield-attributing characters of mungbean and exhibited negative significant correlation with pod length (-0.57), pods/plant (-0.74), pod weight (-0.68), 100 seeds weight (-0.69), 100 seeds swell weight (-0.59), and seed germination (-0.71). These characters had direct or indirect effects on grain yield, which was also adversely affected due to mildew attack (-0.89). Powdery mildew was significantly retarded due to the single spray of carbendazim (0.05%) at 30-day-old crop, where the apparent rate of infection (r) was minimum at 0.0095/ unit/day and with low (11.44%) powdery mildew intensity. Other fungicides like tridemorph (0.075%) and penconazole (0.05%) were equally effective against the mildew disease where the disease intensity was less than 20% and the values of r were 0.0134 and 0.039/unit/day respectively, as compared with the control at 0.267/unit/day. Fungicide spray influenced the yield-attributing characters besides controlling the disease. Such effects were more pronounced in carbendazim (0.05%)-treated plots due to its phytotonic nature where pod length (7.59cm), pods/plant (29.75), pod weight (8.16 g), 100 grain weight (3.94 g), and swell weight of 100 seed (9.49 g) were maximum resulting to the highest yield (480 kg/ha) as compared with that of control (224 kg/ha). Spray of carbendazim also improved seed germination (74.5%). Spray of other fungicides like carbendazim with copper oxychloride in 1:1 ratio, tridemorph (0.075%), and penconazole (0.05%) was equally effective against powdery mildew of mungbean. These fungicides also exhibited positive effects on yield-attributing characters of the crop and finally increased yield. These systemic fungicides were more effective in controlling powdery mildew disease of V. radiata in the rainy season compared with wettable sulphur.

• Mycobiology
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• v.45 no.4
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• pp.409-420
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• 2017

Foliar sprays of three plant resistance inducers, including chitosan (CH), potassium sorbate (PS) ($C_6H_7kO_2$), and potassium bicarbonates (PB) ($KHCO_3$), were used for resistance inducing against Erysiphe cichoracearum DC (powdery mildew) infecting okra plants. Experiments under green house and field conditions showed that, the powdery mildew disease severity was significantly reduced with all tested treatments of CH, PS, and PB in comparison with untreated control. CH at 0.5% and 0.75% (w/v) plus PS at 1.0% and 2.0% and/or PB at 2.0% or 3.0% recorded as the most effective treatments. Moreover, the highest values of vegetative studies and yield were observed with such treatments. CH and potassium salts treatments reflected many compounds of defense singles which leading to the activation power defense system in okra plant. The highest records of reduction in powdery mildew were accompanied with increasing in total phenolic, protein content and increased the activity of polyphenol oxidase, peroxidase, chitinase, and ${\beta}$-1,3-glucanase in okra plants. Meanwhile, single treatments of CH, PS, and PB at high concentration (0.75%, 2.0%, and/or 3.0%) caused considerable effects. Therefore, application of CH and potassium salts as natural and chemical inducers by foliar methods can be used to control of powdery mildew disease at early stages of growth and led to a maximum fruit yield in okra plants.

• Research in Plant Disease
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• v.28 no.4
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• pp.248-251
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• 2022

In October 2022, common Asian cowpea (Vigna nakashimae) powdery mildew disease was investigated at Yesan-gun, Chungcheongnam-do, Korea (36°40'12.7"N,126°51'36.4"E). The disease mainly occurred on the front of the leaves, and weak powdery mildew disease occurred on the back side of leaf. The chasmothecia was identified on the back side of the leaf. Analysis of the internal transcribed spacer rDNA sequence and 28S large subunit sequence, along with the morphological characteristics of the anamorph and teleomorph of the causal fungus identified as Podosphaera xanthii. This is the first time in Korea to report common Asian cowpea (Vigna nakashimae) powdery mildew disease caused by Podospaera xanthii.

• Research in Plant Disease
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• v.18 no.2
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• pp.80-85
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• 2012

We examined the incidence of powdery mildew in strawberry cv. Seolhyang plants, and performed a comparative analysis on the temperature, photosynthesis rate, and nutrient content of healthy and powdery mildew-infected plants. Powdery mildew first infected the fruit of the strawberries in mid-January, and the disease severity increased in both fruits and leaves during the late harvest season. The rate of photosynthesis and leaf temperatures of healthy plants were higher than those of powdery mildew-infected leaves and significantly decreased with an increase in the disease severity. The healthy and powdery mildew-infected plants in the soil analysis were not significantly different in chemical compositions. The leaves of the healthy plants contained lower potassium and higher manganese and chlorophyll concentrations than the powdery mildew-infected plants. In particular, manganese was significantly higher in healthy leaves than in infected leaves. Therefore, the concentrations of potassium, manganese and chlorophyll in strawberry leaves may be an important factor for disease suppression.

• Research in Plant Disease
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• v.7 no.1
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• pp.31-36
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• 2001

To establish an effective chemical control strategy against powder mildew of sweet pumpkin (Cucurbita maxima Duchesne) caused by Sphaertheca fuliginea, screening of effective fungicides and determination of their application times were conducted. Powdery mildew caused by S. fuliginea began to occur at about 80 days after transplanting and continuously increased until harvesting in Korea. Systemic fungicides, such as difenoconazole, triforine, bitertanol, and triflumizole, were effective for controlling powdery mildew, showing control efficacies of about 80-90%. When the fungicide triflumizole was applied 3 or 4 times from the beginning day of the disease at 10-day intervals, about 92.0% and 94.6% of disease control and yield increase of 7% and 9% were obtained, respectively. Therefore, the proper application of triflumizole for controlling powdery mildew of sweet pumpkin must be done more than 3 times.

• Research in Plant Disease
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• v.22 no.3
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• pp.133-144
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• 2016

Powdery mildew (Podosphaera xanthii) causes severe damage to pumpkin crops grown in open fields and plastic house. Initially, we used ten accessions of pumpkin species; Cucurbita pepo (3), C. maxima (2), C. moschata (2), and C. argyrosperma (3) to study the disease progress in different stages of seedling development. Commercial pumpkin varieties were used as susceptible host for inoculum management and young seedlings were inoculated by dusting powdery mildew spores on the cotyledons, 1-true-leaf and 2-true-leaf seedling stages. Based on initial study, we further evaluated 218 pumpkinaccessions for their resistance to powdery mildew in different seedling stages under plastic house. Area under disease progress curve (AUDPC) and relative AUDPC (rAUDPC) was higher in cotyledonary and 1-true-leaf than 2-true-leaf stage. Seedlings at cotyledons and 1-true-leaf seedling stage displayed more susceptibility to powdery mildew. Based on evaluation of 2-true-leaf stage, IT 110859 and IT 278459 from C. pepo and C. argyrosperma identified as resistant (<0.2). Of the 228 pumpkin accessions, 21 (9.2%) pumpkin accessions consisting of C. pepo (2), C. maxima (5), C. moschata (13), and C. argyrosperma (1) exhibited intermediate resistance (<0.4) to powdery mildew and these accessions are useful to growers for its rational management.

• Research in Plant Disease
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• v.20 no.2
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• pp.95-100
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• 2014

This research was performed to examine the effects of mixed espil and copper hydroxide for powdery mildew prevention on cucumber, tomato and pepper. On prevention effect for powdery mildew on cucumber, results revealed that mixed espil and copper hydroxide with a ratio of 4 : 1, disease incidence rate was 18.9% and prevention effect was 69.9%. Another treatment with a ratio of 8 : 1 showed an disease incidence rate of 18.1% and prevention effect of 71.1%, thus, showed great effectiveness. For powdery mildew on tomato, espil and copper hydroxide were mixed using the ratio 4 : 1, results showed an disease incidence rate of 12.4% and prevention effect of 85.3%. Treatment using the ratio of 8 : 1, results showed an disease incidence rate of 14.3% and prevention effect of 83.0%, thus, showed great effectiveness. For powdery mildew on redpepper, espil and copper hydroxide were mixed using the ratio of 4 : 1 with results showed disease incidence rate of 17.7% and prevention effect of 83.0%. From the results, this treatment is the most effective with the lowest attack rate and highest prevention effect. Deducing from the study, it was found out that using mixed espil and copper hydroxide using the ratios 4 : 1 or 8 : 1 are the most effective method for powdery mildew prevention. Mixed ratio of 4 : 1 or 8 : 1 was most effective for preventing powdery mildew on cucumber and tomato, while the espil and copper hydroxide ratio of 4 : 1 was the most effective method for powdery mildew prevention on pepper.

• Research in Plant Disease
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• v.11 no.2
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• pp.106-114
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• 2005

To breed powdery mildew resistant varieties, 104 accessions of Cucurbita spp. germplasm were evaluated. Powdery mildew resistance and horticultural characteristics of the accessions were investigated in the field conditions. C. martinezii was selected for high resistance to powdery mildew in the field. The growth of powdery mildew pathogen and response of leaf surface tissue to the pathogen were observed after artificial inoculation to resistant C martinezii and susceptible C. moschata cv. 'Wonye No.402'. Mycelium growth was very clearly different between resistant C. martinezii and susceptible C moschata cv. 'Wonye No. 402' at 5 days after inoculation at the adult stage. Interspecific hybridization was attempted to transfer powdery mildew resistance gene(s) from C. martinezii to C. moschata. A single dominant gene action was postulated as deter mining powdery mildew resistance at the seedling stage. But for the effective selection of powdery mildew resistant individuals, it was established that adult plant resistance should be confirmed in the field conditions after the seedling test. Through the seedling and field tests, C. moschata lines resistant to powdery mildew and superior to horticultural characteristics, were selected after 2 backcrossing and 3 selfing generations. The fruit characteristics of newly developed lines were similar to those of the recurrent parent, 'Jaechenjarae'.

• 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.