Orondis products: new fungicide co-packs listed for downy mildew and late blight diseases of cucurbits and fruiting vegetables

Published: December 19, 2016

Orondis, a brand new portfolio in the list of fungicides, is finally introduced from Syngenta at the beginning of this year. The product has been studied under the name DPX-QGU42 in the past several years and many studies reported it to be effective in controlling downy mildews and late blight diseases on cucurbits, fruiting vegetables, herbs, and other crops. I personally had a firsthand experience working with this product and its efficacy in controlling basil downy mildew caused by the oomycete Peronospora belbahrii was excellent. This article highlights some of the recommendations based on the 2017 Midwest Vegetable Production Guide. Before using any of Orondis products, however, growers need to strictly check and follow the currently approved EPA labels www.syngenta-us.com/labels/orondis to find out details on label rates, crops, safety precautions and registry status in Missouri.

Active ingredient of Orondis, Oxathiapiprolin, belongs to U15 mode of action according to the 2016 FRAC (Fungicide Resistance Action Committee) mode of action list. It is labelled as an effective fungicide against a range of diseases caused by oomycetes (fungi like organisms, also known as water molds) on many vegetables. Oxathiapiprolin (OXT) is mobile through xylem and hence systemic. It is claimed to have a novel mode of action, not cross-resistant to any other fungicide. OXT is a single site inhibitor and hence risk of resistance is assumed to be medium to high. At the moment, Orondis is sold as one of the following three co-packs: Orondis Opti, Orondis Ultra, and Orondis Gold. The reason for combining OXT with others in a co-pack could partly be a precautionary step to avoid development of insensitivity to this single site inhibitor fungicide. Growers shall strictly follow the longer Pre-Harvest Interval (PHI) of the two partners in the co-pack before harvesting.

The following is a brief view of these three co-packs in terms of their active ingredient (a.i.), restricted entry interval (REI), pre-harvest interval (PHI) and efficacy (G = good, VG = very good) on cucurbit downy mildew (CDM), cucurbit Phytophthora blight (CPB), Late blight on tomatoes (TLB) and PB on peppers (PPB). Orondis products are also labelled for other crops. A comprehensive detail can be found in the 2017 Midwest Vegetable Production Guide.

Just on December 12, 2016 Syngenta has announced that Orondis Opti is now registered in premix formulation instead of the multi-pack. For any further assistance with Orondis products, you may contact me (Phone: 573-681-5634 or e-mail: mershaz@lincolnu.edu) or any of your county extension educator.

Editor's note: Late blight of tomato hasn't (yet) been a problem in Missouri and downy mildew on Cucurbits is not typical, except in the Bootheel. So for most auction growers, the benefit will likely be as a new product for Phytophthora blight of peppers or Cucurbits.