What's Wrong With My Plant: Powdery Mildew
If the leaves of your plants look like they've been dusted with flour, or you notice small, circular black dots on the leaves, then. . uh oh, you might be dealing with powdery mildew!
While a little of this annoying fungus won't kill your plants, it can weaken them, and it can survive the winter in the soil. So, powdery mildew should be dealt with when you see it to prevent it from spreading.
If Your Plants Are Infected
- Remove infected parts to stop the spread of infection.
- Don't compost, because the fungus can survive and may infect new plants!
- Remove any infect annual flowers or vegetable at the end of the season--the fungus can survive the winter in the soil, and will return to infect new plants next year!
Other Measures to Take
- Only plant resistant varieties (although, in extreme enough conditions, even resistant varieties can develop powdery mildew problems).
- Prune perennials to increase air flow through the plant
- Do not apply nitrogen heavy fetilizers once you notice infection
- Avoid overhead watering
Powdery mildew won't kill your plants, but try to deal with it as soon as you see it, to prevent it from spreading!