Downy mildew of Cucurbits (Pseudoperonospora Cubensis): the Fungus and its hosts, distribution, epidemiology and control

1980 ◽  
Vol 8 (2) ◽  
pp. 109-147 ◽  
Author(s):  
J. Palti ◽  
Y. Cohen
Keyword(s):  
Downy Mildew ◽  
Pseudoperonospora Cubensis ◽  
And Control

scholarly journals EVALUATION OF DIFFERENT FUNGICIDES AGAINST DOWNY MILDEW OF CUCUMBER CAUSED BY PSEUDOPERONOSPORA CUBENSIS

2017 ◽  
Vol 29 (1) ◽  
pp. 153
Author(s):  
Muhammad Waris ◽  
Ahmad Khan ◽  
Lut Fullah ◽  
Atta Ullah
Keyword(s):  
Downy Mildew ◽  
Cucumis Sativus ◽  
Positive Response ◽  
Effective Control ◽  
Pseudoperonospora Cubensis ◽  
Vegetable Crop ◽  
Different Types ◽  
And Control ◽  
Downy Mildew Disease

Cucumis sativus is one of the most important vegetable crop being grown in Pakistan, cucumber is being affected by different types of pathogens and downy mildew is one of the detrimental disease causing losses upto 40%. RCBD design was used for fungicide evaluation, Varieties viz., beithoalfa, Marketmore-76, Cucumber 363, Anmol , Marketmore and Desi were evaluated it was found that all varieties were showed positive response in minimizing disease disease out of which variety Beithoalfa showed the most effective control of disease followed by Marketmore-76, Cucumber 363, Anmol, Marketmore and Desi/Control. Among the treatment of fungicides: Moral fungicide showed most effective control of disease followed by Agrohut, Acute, Antracol, Cabriotop and Control, out of all fungicides “cabriotop” showed the least effective results against downy mildew disease.

The zoospore of Pseudoperonospora cubensis, the causal agent of cucurbit downy mildew

1989 ◽  
Vol 8 (5) ◽  
pp. 511-516 ◽  
Author(s):  
Lene Lange ◽  
Ulla Edén ◽  
Lauritz W. Olson
Keyword(s):  
Downy Mildew ◽  
Causal Agent ◽  
Pseudoperonospora Cubensis ◽  
Cucurbit Downy Mildew

scholarly journals Diagrammatic scale to assess downy mildew severity in melon

2009 ◽  
Vol 27 (1) ◽  
pp. 76-79 ◽  
Author(s):  
Sami J Michereff ◽  
Marissônia A Noronha ◽  
Gaus SA Lima ◽  
Ígor CL Albert ◽  
Edilaine A Melo ◽  
...  
Keyword(s):  
Linear Regression ◽  
Leaf Area ◽  
Downy Mildew ◽  
Pseudoperonospora Cubensis ◽  
Northeast Brazil ◽  
Simple Linear Regression ◽  
Standard Methods ◽  
Accuracy And Precision ◽  
Severity Levels ◽  
Diagrammatic Scale

The downy mildew, caused by Pseudoperonospora cubensis, is an important melon disease in Northeast Brazil. Considering the lack of standard methods for its assessment, a diagrammatic scale was developed with 2, 4, 8, 16, 32, 64, 82, and 96% of affected leaf area. The scale was then checked for its accuracy, precision, and reproducibility in estimating downy mildew severity. The diagrammatic scale was validated by eight disease raters; using 50 leaves with different severity levels, previously measured using the software Assess®. Two evaluations were performed on the same set of leaves, but in a different sequence order, by the same raters, within a 15-day interval. The accuracy and precision of each rater was determined by simple linear regression between the actual and the estimated severity. The scale provided good levels of accuracy (means of 87.5%) and excellent levels of precision (means of 94%), with absolute errors concentrated around 10%. Raters showed great repeatability (means of 94%) and reproducibility (>90% in 90.3% of cases) of estimates. Therefore, we could conclude that the diagrammatic scale presented here was suitable for evaluating downy mildew severity in melon.

scholarly journals Host Preference of Mating Type in Pseudoperonospora cubensis, the Downy Mildew Causal Agent of Cucurbits

Plant Disease ◽  
2013 ◽  
Vol 97 (2) ◽  
pp. 292-292 ◽  
Author(s):  
Y. Cohen ◽  
A. E. Rubin ◽  
M. Galperin
Keyword(s):  
Downy Mildew ◽  
Mating Type ◽  
Host Preference ◽  
Practical Implication ◽  
Natural Infection ◽  
Primary Source ◽  
Pseudoperonospora Cubensis ◽  
Close Proximity ◽  
Detached Leaves ◽  
Classical Genetics

The A2 mating type of Pseudoperonospora cubensis was first discovered in Israel in May 2010 on butternut gourd (Cucurbita moschata) (1). We monitored the occurrence of the A2 mating type of P. cubensis in isolates collected during May 2010 through September 2012 from downy mildew-infected cucurbit crops growing along the coastal plain of Israel. Mating type was determined by oospore production in melon leaf discs co-inoculated with sporangia of a test isolate mixed with sporangia of A1 or A2 tester isolates (2). The A1 and A2 tester isolates were maintained at 14°C (14 h light/day) by repeated inoculation of detached leaves of cucumber and pumpkin, respectively. The 29 isolates that were collected from cucumber (Cucumis sativum) were all A1. Of the 33 isolates collected from pumpkin (Cucurbita maxima), squash (C. pepo), or butternut gourd (C. moschata), 88% were A2 and 12% were A1. The host preference of mating type in P. cubensis was monitored at Bar-Ilan University farm during April to July 2012, among about 800 plants of eight cucurbit species (~100 plants per species) that were grown side-by-side in three adjacent net-houses (two 6 × 50 m and one 6 × 100 m) and exposed to natural infection. Downy mildew developed on cucumber, melon, pumpkin, squash, and butternut gourd, but not on watermelon, sponge gourd (Luffa cylindrica), or Momordica balsamina. Three-hundred and three isolates of P. cubensis were collected and tested for mating type: 123 from cucumber, 53 from melon, 30 from pumpkin, 48 from butternut gourd, and 41 from squash. The cucumber isolates expressed A1, A2, and A1A2 at a ratio of 94.3%, 3.3%, and 2.4%, respectively; the melon isolates 58.5%, 26.4%, and 15.1%; the pumpkin isolates 0%, 96.7%, and 3.3%; the butternut isolate 7.3%, 87.3%, and 5.5%; and the squash isolates 2.4%, 97.6%, and 0%, respectively. A1A2 isolates produce oospores when crossed with either A1 or A2 tester isolates. This is the first evidence suggesting a preference of A1 isolates to Cucumis spp. and of A2 isolates to Cucurbita spp. similar preference was recently observed among Chinese isolates of this pathogen (unpublished data). The mechanism(s) controlling this preference is not known. Classical genetics is currently employed to P. cubensis in order to understand if it derives from true linkage. The practical implication for downy mildew management is that growing cucumber/melon in close proximity to pumpkin/squash/butternut gourd should be avoided as it may enhance oospore production in nature. Oospores in soil were recently shown to serve as a primary source of downy mildew infection in cucumber (3). References: (1) Y. Cohen, A. E. Rubin, and M.Galperin. Plant Dis. 95:874, 2011; (2) Y. Cohen and A. E. Rubin. Eur. J. Plant Pathol. 132:577, 2012; (3) Y. J. Zhang et al. J. Phytopathol. 160:469, 2012.

Pearl Millet Downy Mildew: Problems and Control Strategies for a New Millennium

2008 ◽  
pp. 37-41
Author(s):  
Dale E. Hess ◽  
Ram P. Thakur ◽  
C. Tom Hash ◽  
P. Srm ◽  
Clint W. Magill
Keyword(s):  
Downy Mildew ◽  
Pearl Millet ◽  
Control Strategies ◽  
And Control ◽  
New Millennium

scholarly journals Fungicides for Control of Downy Mildew on Pickling Cucumber in Michigan

2019 ◽  
Vol 20 (3) ◽  
pp. 165-169 ◽  
Author(s):  
Katelyn E. Goldenhar ◽  
Mary K. Hausbeck
Keyword(s):  
Downy Mildew ◽  
Untreated Control ◽  
Field Studies ◽  
Pseudoperonospora Cubensis ◽  
Relative Area ◽  
Disease Progress Curve ◽  
Cucurbit Downy Mildew ◽  
Disease Progress ◽  
Pickling Cucumber ◽  
Progress Curve

Michigan growers rely on fungicides to limit cucurbit downy mildew (CDM), incited by Pseudoperonospora cubensis; resistance of the pathogen to fungicides is a concern. We evaluated fungicides against CDM in Michigan field studies from 2015 to 2017. According to the relative area under the disease progress curve (rAUDPC), in 2015, mandipropamid, propamocarb, fluxapyroxad/pyraclostrobin, copper octanoate, and dimethomorph resulted in disease levels similar to the control. These treatments, along with cymoxanil, were similar to the control in 2016. Fungicides that were ineffective during 2015 and 2016 did not limit CDM in 2017. Famoxadone/cymoxanil and fluopicolide did not limit CDM in 2017. Each year, the following treatments were similar for disease based on rAUDPC data: oxathiapiprolin applied alone or premixed with chlorothalonil or mandipropamid, ametoctradin/dimethomorph, fluazinam, mancozeb/zoxamide, cyazofamid, and ethaboxam. An exception occurred in 2017, when ethaboxam was less effective than fluazinam, oxathiapiprolin/chlorothalonil, and oxathiapiprolin/mandipropamid. Mancozeb and chlorothalonil treatments were similar in 2015 and 2017, according to rAUDPC data. In 2017, yields were increased for oxathiapiprolin/chlorothalonil, oxathiapiprolin/mandipropamid, mancozeb, ametoctradin/dimethomorph, mancozeb/zoxamide, ethaboxam, cyazofamid, chlorothalonil, and fluazinam compared with the untreated control.

Epidemiology, prediction and control of onion downy mildew caused byPeronospora destructor

1989 ◽  
Vol 17 (1) ◽  
pp. 31-48 ◽  
Author(s):  
J. Palti
Keyword(s):  
Downy Mildew ◽  
Prediction And Control ◽  
And Control ◽  
Onion Downy Mildew
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