Updated: 5 June 2009
*** Control Recommendations ***
Ontario's 2009 Downy Mildew Control Strategy for Cucurbits
*** Current links for Fungicide / Disease Information, Production Recommendations, Newsletters, and Factsheets can be found HERE. ***
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Downy mildew is a very destructive disease and progresses rapidly under favorable conditions. Fungicides are much more effective when applied well before symptoms are visible. Initiating a downy mildew control program after symptoms have been detected is much more likely to fail.
Results of fungicide trials from various years are available below. The most effective spray programs in the 2007 trial included the fungicides Tanos, Previcur Flex, and Gavel, tank mixed or alternated with Curzate, Manzate and/or Bravo.
In designing a fungicide program growers should also observe pre-harvest intervals and practice resistance management by alternating products belonging to different fungicide groups.
| Product & Formulation | Pre-harvest Interval (days) | Fungicide Group |
| Bravo 6SC | 0 | M |
| Curzate 60DF | 3 | 27 |
| Gavel 75DF | 5 | 22+M |
| Manzate 75WG | 5 | M |
| Presidio 4F | 2 | 43 |
| Previcur Flex 6F | 2 | 28 |
| Ranman 400SC | 0 | 21 |
| Tanos 50WG | 3 | 11+27 |
For a more complete list of fungicides, click on “2008 Fungicide Efficacy Table” below.
The following is a sample fungicide program for cucumber downy mildew that incorporates field-tested efficacy, observes pre-harvest intervals and practices sound resistance management:
Presidio 4F , 4 oz + Manzate Pro-Stick* 75DG, 2 lb alternated every 5 to 7 days with Previcur Flex 6F, 1.2 pt + Bravo Weather Stik* 6SC, 2 pt.
*Other labeled formulations of mancozeb include Penncozeb and Dithane; other labeled formulations of chlorothalonil include Echo and Equus.
Beginning near harvest and based on the frequency of harvest, use a product(s) with the appropriate pre-harvest interval.
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2009 Vegetable Crop Handbook for the Southeastern U.S.
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2007 Cucumber Fungicide Trial Report
2007 Cucumber Fungicide Timing Report
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2006 Cucumber Fungicide Trial Report
2006 Cucumber Fungicide Timing Report
2006 Squash Fungicide Trial Report
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2005 Relative Efficacy Table