Cucurbit downy mildew (Pseudoperonospora cubensis)—biology, ecology, epidemiology, host-pathogen interaction and control

2010 ◽  
Vol 129 (2) ◽  
pp. 157-192 ◽  
Author(s):  
Aleš Lebeda ◽  
Yigal Cohen
Keyword(s):  
Downy Mildew ◽  
Pseudoperonospora Cubensis ◽  
Cucurbit Downy Mildew ◽  
Host Pathogen Interaction ◽  
Host Pathogen ◽  
And Control

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.

scholarly journals Interactive Effects of Temperature and Leaf Wetness Duration on Sporangia Germination and Infection of Cucurbit Hosts by Pseudoperonospora cubensis

Plant Disease ◽  
2012 ◽  
Vol 96 (3) ◽  
pp. 345-353 ◽  
Author(s):  
K. N. Neufeld ◽  
P. S. Ojiambo
Keyword(s):  
Leaf Area ◽  
Downy Mildew ◽  
Disease Severity ◽  
Leaf Wetness ◽  
Pseudoperonospora Cubensis ◽  
Weibull Function ◽  
Leaf Wetness Duration ◽  
Cucurbit Downy Mildew ◽  
Host Type ◽  
Effects Of Temperature

Outbreaks of cucurbit downy mildew caused by Pseudoperonospora cubensis are dependent on the weather but effects of temperature and leaf wetness duration on infection have not been studied for different cucurbits. To determine the effects of these two weather variables on sporangia germination and infection of cucurbit host types by P. cubensis, three host types; cucumber (‘Straight 8’), cantaloupe (‘Kermit’), and acorn squash (‘Table Queen’), were inoculated and exposed to leaf wetness durations of 2 to 24 h at six constant temperatures ranging from 5 to 30°C in growth-chamber experiments. Sporangia germination was assessed after each wetness period, and leaf area infected was assessed 5 and 7 days after inoculation. Germination of sporangia was highest on cantaloupe (16.5 to 85.7%) and lowest on squash (10.7 to 68.9%), while disease severity was highest and lowest on cucumber and cantaloupe, respectively. Host type, temperature, wetness duration and their interactions significantly (P < 0.0001) affected germination and disease severity. Germination and disease data for each host type were separately fitted to a modified form of a Weibull function that characterizes a unimodal response and monotonic increase of germination or infection with temperature and wetness duration, respectively. The effect of host type on germination and infection was characterized primarily by differences in the upper limit parameter in response to temperature. Differences among host types based on other parameters were either small or inconsistent. Temperature and wetness duration that supported a given level of germination or infection varied among host types. At 20°C, 15% leaf area infected was expected following 2, 4, and 8 h of wetness for cucumber, squash, and cantaloupe, respectively. When temperature was increased to 25°C, 15% disease severity was expected following 3, 7, and 15 h of wetness for cucumber, squash, and cantaloupe, respectively. Risk charts were constructed to estimate the potential risk of infection of cucurbit host types by P. cubensis based on prevailing or forecasted temperature and leaf wetness duration. These results will improve the timing and application of the initial fungicide spray for the control of cucurbit downy mildew.

scholarly journals The cucurbit downy mildew pathogen Pseudoperonospora cubensis

2010 ◽  
Vol 12 (3) ◽  
pp. 217-226 ◽  
Author(s):  
ELIZABETH A. SAVORY ◽  
LEAH L. GRANKE ◽  
LINA M. QUESADA-OCAMPO ◽  
MARINA VARBANOVA ◽  
MARY K. HAUSBECK ◽  
...  
Keyword(s):  
Downy Mildew ◽  
Pseudoperonospora Cubensis ◽  
Cucurbit Downy Mildew

scholarly journals Effect of Fungicide Program on the Development of Downy Mildew in Three Cucurbit Crops in New Jersey

2017 ◽  
Vol 18 (3) ◽  
pp. 181-185 ◽  
Author(s):  
Christian A. Wyenandt ◽  
Wesley L. Kline ◽  
Daniel L. Ward
Keyword(s):  
Downy Mildew ◽  
Agricultural Research ◽  
Pseudoperonospora Cubensis ◽  
High Input ◽  
Pathogen Population ◽  
Crop Species ◽  
Cucurbit Downy Mildew ◽  
Summer Squash ◽  
Extension Center ◽  
Winter Squash

From 2014 to 2016, five fungicide programs of varying fungicide efficacy were evaluated for the control of cucurbit downy mildew (Pseudoperonospora cubensis) on three different cucurbit crops at the Rutgers Agricultural Research and Extension Center (RAREC) in Bridgeton, NJ. The five fungicide programs were: (i) no fungicide input; (ii) low-input (chlorothalonil only); (iii) medium-input (protectant + 2 downy mildew-specific fungicides [Tanos, Curzate]); (iv) high-input (protectant + 2 downy mildew-specific fungicides [Ranman, Presidio]); or (v) high-input (protectant + 3 downy mildew-specific fungicides [Previcur Flex, Ranman, Zampro]). The three cucurbit crops were cucumber cv. Marketmore 76, zucchini cv. Reward (summer squash), and acorn squash cv. Taybelle (winter squash). In 2014, only cucumber was infected by the pathogen. In 2015 and 2016, all three cucurbit hosts were infected by downy mildew at varying severities suggesting that the P. cubensis population may have differed compared with 2014. In all three years control of downy mildew was significantly higher when downy mildew-specific fungicides were included in weekly rotations. In some years, no fungicides, broad-spectrum fungicides only, or fungicides with moderate or lower efficacy for downy mildew may provide adequate control on certain cucurbit crop species depending on the current cucurbit downy mildew pathogen population.

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