Downy Mildew: Symptoms, Causes & Control

What it looks like

Pale yellow to yellow-brown angular lesions form on the upper leaf surface with a gray-purple mold in the matching spot underneath. Lesions merge, the leaves die back and the plant declines early.

Causal organisms: Bremia centaureae, Bremia lactucae, Bremia taraxaci, Hyaloperonospora brassicae, Hyaloperonospora lobulariae, Hyaloperonospora parasitica, Paraperonospora minor, Peronosclerospora maydis and 25 more

What other growers did about it

A page like this one can tell you what downy mildew is and what to try. What it cannot tell you is what actually happened to someone who had it on the same plant, at the same point in the season, and what they did next.

Gadenin is a free garden journal built around that. You photograph the plant, tag what you are seeing, and the entries line up by date for each plant you grow.

• Tag the problem and the app tells you how many other growers have logged the same thing on the same plant.
• Growers who make their records public can be followed, so you can read what they did and how it turned out.
• Next season your own entries come back at the same point in the year, so you check the plant before it starts.

Affected plants (64)

Plants with this problem on record.

Written byYasuGrowing vegetables and fruit in Chiba, Japan, and building Gadenin. Corrections are welcome. 15 years of growing.