The label is the law. Read your product's label before you mix or apply; the rates here come from the labels listed under Sources.
- Active ingredient
- Copper octanoate (copper soap); other products use copper hydroxide, sulfate or oxychloride
- Chemical class
- Inorganic copper contact fungicide and bactericide; copper octanoate combines soluble copper with a naturally occurring fatty acid to form a copper soap.[1]
- Mode of action
- FRAC Group M01: Multi-site contact activity: inorganic (copper, different salts)[3]
- Signal word
- Cueva Fungicide Concentrate (copper soap; also sold as Bonide Copper Fungicide): Caution[2]
How it works
Copper acts on bacteria and fungi on contact, which is why the label says to spray before disease is visible or as soon as it first appears.[1][2]
Copper is FRAC group M01, a multi-site mode of action, as opposed to the single-site groups such as the DMI fungicides (group 3).[3]
Timing by disease
For downy mildews, leaf and fruit spots, blights and rust, the label says to start 2 weeks before the disease normally appears or when a long wet spell is forecast; to prevent fruit rots, start at flowering and repeat every 7 to 10 days until harvest.[2]
Where it is used
Start before disease shows or as soon as it appears, spray all plant parts, try to allow at least 12 hours of dry weather afterward, and reapply after rain.[2]
Copper can injure some plants: on some rose varieties it shows as purple spots, and in damp, cool weather below 60°F injury to roses and shrubs is likely; test-spray a plant first.[2]
The label caps yearly use at 373 fl oz of product per 1,000 sq ft on ornamentals and 391 on turf, with lower crop-specific caps on vegetables and fruit.[2]
Products and registrations
| Product | Registrant | EPA Reg. No. | Active % | Formulation | Signal word |
|---|---|---|---|---|---|
| Cueva Fungicide Concentrate (copper soap; also sold as Bonide Copper Fungicide)[2] | W. Neudorff GmbH KG | 67702-2 | 10.0% | liquid concentrate | Caution |
Label rates
| Product | Use | Pests | Rate |
|---|---|---|---|
| Cueva Fungicide Concentrate (copper soap; also sold as Bonide Copper Fungicide) | Vegetables, fruit trees, grapes, roses and ornamentals in home gardens | Peach leaf curl, fire blight, black spot, downy and powdery mildew, leaf spots, blights, anthracnose | 0.5–2.0 fl oz per gal of water[2] Spray 1.1 to 2.3 gallons of the mix per 1,000 sq ft, covering both sides of the leaves, usually every 7 to 10 days. On roses: 1.44 fl oz per gallon for black spot, 1.08 fl oz for powdery mildew. Each crop also has a yearly limit per 1,000 sq ft on the label. |
How to apply it, step by step
1. Protective gear
- The home-use sublabel lists no protective gear: it is harmful if swallowed or absorbed through the skin, so keep it off your skin, out of your eyes and off your clothing.[2]
- Wash your hands with soap and water after handling and before eating, drinking or using the toilet, and wash contaminated clothing before wearing it again.[2]
2. Before you spray
- It is toxic to fish and aquatic invertebrates and can run off for months after use, especially from poorly drained soils or where the water table is shallow: don't spray it on or next to water, and don't dump rinse water where it can reach water.[2]
- Keep adults, children and pets out of the spray and drift.[2]
- If you can, spray when at least 12 hours of dry weather will follow.[2]
3. Mixing
- Shake well, then mix 0.5 to 2 fl oz in a gallon of water; use the higher rate for diseases that go dormant and overwinter.[2]
- A ready-to-spray hose-end bottle dilutes it automatically; start at the far end of the area and work back toward the faucet so you don't walk through what you've sprayed.[2]
4. Applying
- Spray all plant parts thoroughly, tops and bottoms of leaves, at 1.1 to 2.3 gallons of diluted spray per 1,000 sq ft unless the crop table says otherwise.[2]
- Start before disease shows or as soon as it appears, and repeat every 7 to 10 days unless the crop table gives another interval; respray after rain.[2]
- For downy mildew, leaf spots, blights and rust, begin about 2 weeks before the disease usually appears or when a long wet spell is forecast; to prevent fruit rots, start at flowering and repeat every 7 to 10 days until harvest.[2]
5. After you spray
- Keep people and pets out of the treated area until the spray has dried.[2]
- It can be used up to the day of harvest.[2]
- After a hose-end sprayer, turn the knob to OFF, shut the faucet, drain the hose, reseal the bottle and rinse the applicator.[2]
First aid
- In the eyes, hold them open and rinse slowly and gently with water for 15 to 20 minutes, removing contact lenses after the first 5 minutes; on skin or clothing, take off contaminated clothing and rinse for 15 to 20 minutes.[2]
- If swallowed, call a poison control center or doctor right away, have the person sip a glass of water if they can swallow, and don't induce vomiting unless told to; the label lists poison control at 1-800-222-1222.[2]
Storage, spills and disposal
- Store it closed and resealed in a secure place away from open flame; freezing can damage it, so don't store it below 4°C (39°F).[2]
- Soak up spills with an absorbent material and dispose of it properly.[2]
- Put an empty container in the trash or recycling; for a partly full one, call your local solid waste agency, and never pour product down a drain.[2]
From the safety data sheet
- The concentrate is a blue liquid with a fatty odor containing 10 percent copper octanoate (copper soap), and it is not flammable.[4]
- The SDS signal word is Caution: it is harmful if swallowed or absorbed through the skin, so avoid contact with skin, eyes and clothing and wash your hands after handling.[4]
- It is toxic to fish and other aquatic organisms: don't apply it directly to water, and keep drift, runoff and equipment rinse water out of waterways.[4]
- For spills, stop the leak if it is safe to do so, absorb or cover the liquid with dry material, and keep runoff out of waterways and sewers.[4]
- Store the closed container in a well-ventilated place at ordinary temperatures, away from excessive heat and from strong oxidizers or acids.[4]
Safety and environmental hazards
People
The label signal word is CAUTION: harmful if swallowed or absorbed through the skin; wash hands after handling.[2]
Pets
Keep people and pets out of the treated area until sprays have dried, and do not spray where it will drift onto them.[2]
Bees and pollinators
The home and garden label carries no bee warning.[2]
Fish and water
The label states it is toxic to fish and aquatic invertebrates and can run off for several months or more after application, especially from poorly draining soils or soils with a shallow water table; never apply where surface water is present.[2]
Common questions
- How much copper fungicide per gallon?
- The Cueva home garden label calls for 0.5 to 2.0 fluid ounces per gallon of water, sprayed at 1.1 to 2.3 gallons per 1,000 square feet.[2]
- Can copper fungicide burn my plants?
- Yes. Some roses show copper injury as purple spots, injury is likely in damp weather below 60°F, and the label says to test-spray first.[2]
- Is copper fungicide bad for fish?
- Yes. It is toxic to fish and aquatic invertebrates and can run off treated ground for months.[2]
Sources
- University of California Statewide IPM Program, “Home and Landscape Pesticide Active Ingredients Database: copper octanoate.” ipm.ucanr.edu/home-and-landscape/pesticide-active-ingredients-database/active-ingredient-details/?uaiKey=125 (accessed 2026-10-06)
- U.S. EPA Pesticide Product Label System, “Cueva Fungicide Concentrate (NEU1140F Copper Soap) label, EPA Reg. No. 67702-2 (EPA-stamped, July 8, 2021).” www3.epa.gov/pesticides/chem_search/ppls/067702-00002-20210708.pdf (accessed 2026-10-06)
- Fungicide Resistance Action Committee, “FRAC Code List 2025.” www.frac.info/media/ljsi3qrv/frac-code-list-2025.pdf (accessed 2026-10-06)
- Certis USA LLC, “Cueva Fungicide Concentrate Safety Data Sheet (Certis USA, compiled May 21, 2015; EPA Reg. No. 67702-2-70051, a supplemental distributor registration of the page's 67702-2 label; copy hosted on a retailer's Shopify file store).” cdn.shopify.com/s/files/1/0559/1256/2893/files/Cueva_sds.pdf (accessed 2026-10-17)