Downy Mildew Fungicide Recommendations – Cucumbers and Muskmelons:
These recommendations are for cucumbers, which are highly susceptible to downy mildew. A less intense fungicide program may be necessary for other vine crops.
Protection before disease appears (downy mildew is not present in your county/growing area): Apply one of the following fungicides on a 7-10 day schedule: chlorothalanil (e.g. Bravo Weather Stik) or mancozeb (e.g. Manzate or Dithane). The application interval can be lengthened under dry conditions. Use the shorter interval under cool, moist conditions.
Protection before disease appears (downy mildew is in your county/area but not in your fields): Apply one of the following fungicides on a 7-10 day schedule, tank mixed with Bravo, Manzate or Dithane: Gavel, Previcur Flex, Tanos, Ranman, Curzate or Presidio. Alternate products. The application interval can be lengthened under dry conditions. Use the shorter interval under cool, moist conditions.
Management after disease appears: Apply one of the following fungicides on a 5-7 day schedule, tank mixed with Bravo or Dithane: Previcur Flex, Tanos, Ranman or Presidio. Alternate products. The application interval can be lengthened under dry conditions. Use the shorter interval under cool, moist conditions.
Note that the fungicides recommended above have different preharvest intervals (PHI). Keep this in mind for fungicides applied after harvesting begins.
| Product | Efficacy | Rate | PHI (Days) |
|---|---|---|---|
| Presidio | +++++++++ | 3.0-4.0 fl oz 4SC/A | 2 |
| Ranman | +++++++++ | 2.1-2.75 fl oz 400SC/A
plus an adjuvant |
0 |
| Previcur Flex | +++++++ | 1.2 pt 6F/A | 2 |
| Tanos | ++++++ | 8.0 oz 50WDG/A | 3 |
| Curzate | ++++++ | 3.2 oz 60 DF/A | 3 |
| Gavel* | +++++ | 1.5-2.0 lb 75DF/A | 5 |
| Protectant fungicides | (tank mix | partners) | |
|---|---|---|---|
| Bravo Weather Stik | ++++ | 1.5-2.0 pt/A | 0 |
| Dithane or Manzate | ++++ | 3.0 lb 75DF/A | 5 |
*Contains mancozeb, which is a protectant and therefore does not need to be tank mixed with another protectant product
What about other vine crops?
We have not had any confirmed reports of downy mildew in any vine crops in Ohio except cucumber and muskmelons. The next most susceptible vine crop is pumpkin and other squashes and watermelon.
Credit: Ohio State University – Dr. Sally Miller