Orondis® Fungicide Available for use in California Avocado Groves

  • Nov 29, 2021

California avocado growers received an early Thanksgiving surprise on Wednesday, November 24 when Syngenta announced their product Orondis® Fungicide had been granted full registration for use against Phytophthora root rot in California avocado groves.

Orondis® (Oxathiapiprolin) is an entirely new type of fungicide belonging to FRAC class 49 (Fungicide Resistance Action Committee). Orondis® works directly against the Phytophthora propagules in the soil, rather than against the pathogen in the tree, effectively eradicating the pathogen from treated soil for a period following application.

The labeled rate for Orondis® on avocados is 4.8 fl. oz./acre up to 9.6 fl. oz./acre. Syngenta recommends the 4.8 fl. oz./acre rate for maintenance programs utilizing a 6-month retreatment program, or the 9.6 fl. oz./acre rate for a 12-month retreatment program. For heavy/severe infections and/or to start off using a strong program before reverting to a maintenance program, Syngenta recommends considering using the higher end of the labeled rates on a 6-month retreatment program for the first year. Importantly, Orondis® is limited to no more than two sequential applications before rotating to a fungicide with a different mode of action (non-FRAC class 49). In trials, Ridomil Gold® SL at 16 oz./acre was an effective product to use in rotation with Orondis®. Orondis® has a Restricted Entry Interval of 4 hours and a Preharvest Interval of 30 days.

Orondis® is approved for application through drip or microsprinkler irrigation only. The soil should be wetted prior to injecting Orondis®, and the product must be incorporated with 8-12 hours of irrigation. Dakota Camino, Syngenta Sales Representative, states, “A minimum of 8 hours and maximum of 12 hours of water is often most efficient for incorporation; I would not advise using less than 6 hours of water to incorporate Orondis® and I would not advise using more than 12 hours of water to incorporate Orondis® in most systems.”

Growers need to be aware that existing stocks of product have labels that do NOT include avocados. Therefore, growers must have in their possession at the time of application the product’s supplemental label that includes avocados, until new product with an updated label is available. A copy of the supplemental label is available in the right-hand navigation.

Also, it is important to know that nut crops in California were added to the label at the same time avocados were added. There are over 1 million acres of nut crops in California compared with about 50,000 acres of avocados. Syngenta is doing everything they can to ensure product is available to any grower wishing to apply Orondis® to avocados, but orders will be filled on a first-come-first-served basis. Growers should speak with their Pest Control Advisor immediately to develop their treatment plan for 2022 and get their order in as soon as possible.  

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