DiseasePowdery mildew control

Microbial biocontrol against powdery mildew control

The effectiveness, measured

58 /100

Time horizon: 1 season

Why it works

Some microbes (e.g. Bacillus, Ampelomyces) reinforce powdery-mildew protection, allowing sulfur to be cut.

What to measure for this pairing

Powdery-mildew severitySulfur replaced

Why this problem matters

Powdery mildew (Erysiphe necator) thrives in warmth and moderate humidity, without needing rain. Under organic rules it is fought mainly with sulfur, complemented by bicarbonates, extracts and biocontrol agents.

Efficacy depends on timing and coverage: start early, in the sensitive post-budburst phase, and hold protection to veraison. An open canopy and close monitoring cut the number of applications needed.

Problem indicators

Sulfur applications per seasonLeaf and cluster severitySpray canopy coverage

Certification & rules: Decisive for organic harvest quality; sulfur is an authorised input.

How to apply the means

  1. 1Choose the agent suited to the target (e.g. Aureobasidium for botrytis).
  2. 2Apply preventively, respecting viability conditions.
  3. 3Integrate into a programme with copper, sulfur and prevention.
  4. 4Log as an authorised input in the notebook.

Frequently asked

Does biocontrol replace copper and sulfur?

Rarely in full. It is most effective as part of an integrated programme, reducing dependence but not eliminating contact means in high-pressure years.

Are the products sensitive to conditions?

Yes — being living organisms, temperature, UV radiation and tank-mix compatibility affect viability. Following the guidance is essential.

Same means, other problems

Same problem, other meansPowdery mildew

Related reading →Biodynamic preparations: how and when to apply 500, 501 and the compost preps

How GrapeFlow helps

The proof organic certification demands — logged by plot and date.

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.

Downy & powdery mildew risk models

Per-plot disease risk from local weather, to treat at the right moment and spend less copper and sulfur.