Sulfur
The reference means against powdery mildew, authorised in organic.
Sulfur is the main means of powdery-mildew control in organic viticulture. It acts by contact and vapour phase, inhibiting the fungus, and has secondary action on some mites.
Efficacy depends on temperature (it works better in warmth), coverage and timing — start early and protect the sensitive phase. It is cheap and well tolerated, but needs care over phytotoxicity in extreme heat and over pre-harvest intervals.
Effort
Medium — several applications in spring/early summer.
Cost
Low — a cheap and effective input.
Time to result
Immediate within the season.
What it works against
Effectiveness by problem — click through for detail and metrics.
How it works
Sulfur releases vapour that interferes with the powdery-mildew fungus’s respiration, protecting the surface and nearby zones by diffusion.
How to apply
- 1Start early, in the sensitive post-budburst phase.
- 2Apply with good coverage and renew as growth advances.
- 3Avoid applications in extreme heat (phytotoxicity).
- 4Respect the pre-harvest interval.
What to measure
Frequently asked
Can sulfur cause phytotoxicity?
Yes, in extreme heat (above ~30–32 °C). Avoid applying in the hottest hours and during heatwaves.
Does sulfur also control mites?
It has a useful secondary acaricidal action against some mites, though that is not its primary purpose.
Related reading
Related means
How GrapeFlow helps
Apply and document this means by plot, with an audit-ready history for certification.
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
Every treatment logged with product, rate and active substance, flagging what is allowed under organic rules — an audit-ready history.
Electronic field notebook
All operations — weeding, green manure, biocontrol — logged by plot and date, ready for organic certification.