Fungus on Corsican Mint
Answered by: Inge Poot
Question from: Chuck
Posted on: January 18, 1999

I’m growing Corsican mint indoors this winter. Each of the leaves has a number of black, fuzzy, pin-head sized spots. It appears to be some type of fungus. The mint leaves are left dessicated and drained of color, and many of the stems have died back to the soil surface. Any thoughts on what it might be and how to eradicate it.

There are very few options for organic fungus control. You can try spraying the plant with flower of sulphur in a water suspension, but it may not be effective for the particular fungus.

You could also swish the plant upside down in water with a bit of dishwash detergent added. This will wash off any loose spores and maybe even wash off any waxy cuticle the fungus might have and it will then dry the fruiting hyphae sticking up into the air and in this way drastically reduce new spot formation. Repeat this once a day for several days and if it works repeat as soon as new spots seem to appear.

To make the plant less susceptible to fungus, keep it in good light, feed it moderately - you don’t want lush soft growth.

In any case, you should change the environment of the plant such that conditions are very unfavourable for fungus growth. Keep the plant only barely moist (without letting it dry out), never wet the leaves and have good air movement around the plant.

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