Orondis: a new fungicide for downy mildew, late blight and Phytophthora blight management

Orondis (Syngenta Crop Protection) is a new fungicide effective against a range of oomycete pathogens in vegetables, potatoes and other crops that will be available in 2016. There has been a lot of buzz about this product, because it has been evaluated over the past several years in many states, and has proven to be highly effective against downy mildews and late blight. And while it cannot be relied on as the sole management practice for Phytophthora blight, especially in cucurbits, it is the best product I have seen to suppress this disease in squash and peppers in many years. Orondis has a different mode of action (FRAC Group U15) than other fungicides effective against these diseases, and will be a good partner in fungicide programs in crops and locations where one or more of them are a problem.

Cuc DM-5compressed

Cucumber downy Mildew


Tomato late blight


Cucumber Phytophthora blight







The active ingredient in Orondis A is oxathiapiprolin (OXTP). The pre-harvest interval (PHI) for Brassica head and stem vegetables, bulb vegetables, cucurbits, fruiting vegetables, and leafy greens (lettuce, spinach) is 0 days. Longer PHIs are required for potatoes (5 days), tobacco (7 days), and ginseng (14 days).

The marketing of Orondis is a little confusing for 2016 – so this is what I have been told by Syngenta:

In order to protect this product from overuse or misuse and possible development of insensitivity in the pathogens that cause these diseases, Orondis will be sold as one of the following co-packs (both products in same box, two separate bottles, plus two separate labels):

  • Orondis Opti = OXTP (A) + Bravo WeatherStik (B)
    • Downy mildew, Phytophthora blight and late blight management
  • Orondis Ultra = OXTP (A) + Revus (B)
    • Can be used for Phytophthora blight, late blight
  • Orondis Gold = OXTP (A) + Ridomil Gold*
    • Can be used for Phytophthora blight, late blight
    • *Some Phytophthora capsici (Phytophthora blight) and infestans (late blight) populations are insensitive to Ridomil
    • Ridomil Gold is not labeled for cucurbit crops
    • Cucurbit downy mildews are insensitive to Revus and Ridomil Gold in Ohio

At some point these products will be sold as pre-mixes.

Make sure to follow the longer PHI of the two partners in the co-pack. See the Orondis and co-pack partner labels for PHIs as well as for plant-back restrictions.

Resistance management is CRITICAL to maintain the efficacy of OXTP and other specific fungicides. The following restrictions apply to most vegetable crops on the Orondis A label; see labels for full instructions:

  • 0-4.8 fl oz/A, 5-14 day application interval
  • MAX six foliar applications, 19.2 fl oz/A/yr
  • No more than two sequential applications of Orondis before switching to a fungicide with a different mode of action
  • Not more than 33% of foliar fungicide applications
  • Rotate with fungicides with different mode of action
  • Do not follow soil applications of Orondis with a foliar application of Orondis Ultra A

Approximate Orondis pricing:

All are 20 acre Co-packs containing a jug of Orondis and a jug of the companion fungicide

Orondis Gold (Ridomil) approx. cost / acre = $64.00

Orondis Opti (Bravo WS)  approx. cost / acre based on vine crop rate =$42.00

Orondis Opti (Bravo WS)  approx. cost / acre based of fruiting crop rate = $32.00

Orondis Ultra (Revus) approx. cost / acre = $30.14