Copper Fungicides for Organic Disease Management in Vegetables

There are several different copper fungicides approved for use in organically-produced crops. Copper fungicides are important tools for managing diseases that cannot be effectively managed with cultural practices alone. They have broad-spectrum activity, acting on bacteria as well as fungi. Following many years of use, there is a lot more information on efficacy of copper fungicides than the newer biological products. Manufacturers of some biologicals recommend that they be used in a management program with copper fungicides (often in alternation or at low label rate). Thus it appears copper fungicides will continue to be important for managing diseases. Copper fungicides differ in their active ingredient, use rate, re-entry interval, and the amount of copper. Copper is an inorganic compound thus it does not breakdown like organic compounds and consequently copper can accumulate in soil when used intensively. Plants take up some copper from soil because it is a micronutrient. Similarly, humans need a small amount of copper in their diets. Metallic copper equivalent (MCE) is a commonly used measure of the quantity of copper in fungicides.
Click here for a chart on the Highest Label Rate of Organic Copper Fungicides for Some Vegetable Crops.
The specific directions on fungicide labels must be adhered to. They supersede these recommendations (above), if there is a conflict. Check state registration and organic approval before using a product. Any reference to commercial products, trade or brand names is for information only; no endorsement is intended.
Highest Label Rate of Organic Copper Fungicides for Some Vegetable Crops (pdf; 198KB)


Upcoming Events
2025 Muck Onion Growers Twilight Meeting in Oswego

June 26, 2025
Oswego, NY
Open to all Onion Enthusiasts, the Muck Onion Growers Twilight Meeting will include new fungicide recommendations for Botrytis leaf blight and Stemphylium leaf blight, onion maggot seed treatment update, herbicide demonstration tour, and more. This educational event is immediately followed by a catered dinner; both are FREE thanks to generous sponsors!
2.0 DEC recertification credits available in categories 1a, 10 and 23.
Vegetable Pest and Cultural Management Field Meeting for Auction Growers -- Ontario Produce Auction

July 15, 2025
Stanley, NY
This evening meeting will demonstrate pest management in fresh market vegetables in both field and greenhouse (high tunnel) vegetables, primarily for those growing for wholesale auction. A hands-on demonstration of weed, insect and disease identification in vegetables including management options. Details on each topic will focus on field observations at the farm.
Orleans Summer Vegetable Meeting, 2025

July 16, 2025
Waterport, NY
Meeting themes are pest management in a wide array of produce and best practices for pesticide use. Professor Brian Nault will cover allium leaf miner and thrips in onions, garlic, and leeks, and discuss insect challenges in other crops. Bring your questions! We'll also have a field walk that includes high tunnel tomato and cucumber.
DEC credits available: 0.5 in CORE plus either 1.25 in 1a and 23, or 0.75 in 24.