Syngenta’s new fungicide Orondis Ultra is labelled for protecting potatoes against late blight for up to 21 days, however it’s also a good fit for preventing downy mildew in cucurbits, onions and leafy vegetables.  
    

Downy mildew is proving more problematic every year, especially in cucumbers. The disease does not overwinter in Canada, but is reintroduced each year by spores that are carried on winds from the southern United States. It’s not a disease controlled by crop rotation. Every year, it’s a blank slate on what disease pressure may develop. Some growers follow the disease tracking website from North Carolina University, while most rely on OMAFRA warnings. Once Ohio and Michigan have reports of downy mildew, then Ontario and Quebec growers must step up their protection program. 
    

“It’s shocking to the industry how quickly disease resistance has grown right across North America to new fungicides,” says Jim Anderson, Syngenta’s agronomic service representative for eastern Canada.  “Orondis Ultra is unique in that it can work on these water molds – oomycetes – that infect leaves, and has no cross resistance to other products.” 
    

As Anderson explains, this new product is unique in that it is a true systemic. That means the active ingredient -- oxathiapiprolin – moves through the xylem up into new growth, providing up to two weeks of protection in the new developing leaves. The product is very active at low rates. 
    

The company is co-packing Orondis Ultra with mandipropamid, the same active found in the fungicide Revus . One case will treat 50 acres. This is a stewardship program to help prevent resistant strains by using two modes of action.   
    

Here’s how Anderson recommends product use.
•    Both parts of the boxed product should be added to the tank, Orondis Ultra A first followed by Orondis Ultra B for mixing order
•    For cucumbers, add a broad spectrum protectant such as BravoZN
•    Use Orondis Ultra as a preventative product not a rescue
•    Use the product no more than in one-third of the entire season’s spray program
•    Never use Orondis Ultra back to back – use at least two other modes of action before returning to Orondis Ultra
    

This product is best used as a preventative once disease is reported in nearby states. Second plantings at this time can benefit from band spraying for lower cost. Move to broadcast 
spraying once the canopy is in place. 
    

The label has pre-harvest interval of zero days and re-entry interval of 12 hours. Always consult the label before use. For more information, go to www.syngenta.ca.