Copper
The backbone of organic downy-mildew control — to be managed with precision.
Copper is the pillar of downy-mildew protection in organic viticulture. It acts by contact, protecting only the treated surface, so it demands good coverage, renewal after rain and preventive timing.
The big constraint is regulatory and environmental: the EU caps copper at 28 kg/ha over 7 years. Managing it well means using the minimum effective rate, backing the decision with risk models and rigorously summing every application to never breach the ceiling.
Effort
Medium — several applications through a wet spring.
Cost
Low to medium per application; the real cost is the copper ceiling.
Time to result
Immediate protection; the copper balance is managed over 7 years.
What it works against
Effectiveness by problem — click through for detail and metrics.
Downy mildew control
It is the reference means against downy mildew in organic: it protects leaf and cluster by contact against spore germination.
Time horizon: Immediate
What to measure for this pairing
Botrytis control
Copper has a secondary skin-hardening effect and action on cluster flora, contributing modestly against botrytis.
Time horizon: 1 season
What to measure for this pairing
How it works
Copper ions inhibit downy-mildew spore germination on the leaf surface; being non-systemic, it only protects tissue covered at the moment of infection.
How to apply
- 1Treat preventively ahead of forecast infection periods.
- 2Use the minimum effective rate and good spray technology.
- 3Renew after significant rain or strong growth.
- 4Log each application and track the 7-year mean.
What to measure
Frequently asked
What is the copper limit under organic rules?
In the EU, 28 kg of metallic copper per hectare over 7 years (a 4 kg/ha/yr average). Every application must be summed within that rolling window.
How do I cut copper without losing the crop?
By treating on risk models instead of a calendar, at the minimum effective rate, with good coverage and more efficient formulations — and logging everything to optimise season over season.
Related reading
Related means
How GrapeFlow helps
Apply and document this means by plot, with an audit-ready history for certification.
Copper balance (7-year mean)
In Portugal, every copper application is summed automatically on the 7-year rolling mean, per plot — direct control of the EU 28 kg/ha cap that certification audits.
Downy & powdery mildew risk models
Per-plot disease risk from local weather, to treat at the right moment and spend less copper and sulfur.
Phytosanitary register with authorised inputs
In Portugal, every treatment is logged with product, rate and active substance, flagging what is allowed under organic rules — an audit-ready history.