White blotches cosisting of fungus looking threads have formed on the leaves.

Papaya (pawpaw)    South Africa, Western Cape

Some of the older leaves have dried out. The plant has not been getting to much sun, seeing as winter just past. What do i do to remove the fungi looking patches?

Posted by: Zander Folscher (2 points) Zander Folscher
Posted: August 11, 2015


This looks like it could be powdery mildew. Are the yellow patches because of infections on the underside of the leaf? If powdery mildew is the cause of the issue, there are some steps you can take to reduce further infections. Avoid watering with overhead sprinklers, as this can increase humidity. Also, make sure the plant is receiving adequate nutrition, but avoid overuse of nitrogen, because this can promote growth of highly susceptible plant tissue. You can remove and destroy heavily infected leaves, which will both reduce the number of spores available to reinfect the plant and also open up the canopy, reducing humidity. Sulfur fungicides can be used if absolutely necessary, but cultural controls are often adequate to control this disease. The following link has some more info, if you are interested:


Posted by: Gregory James Reynolds (3 points) Gregory James Reynolds
Posted: August 11, 2015

A spray of milk apparently kills off the mildew. I tried this on my zucchini and if seemed to work although the plant was in pretty bad shape. I still managed to harvest afterwards.

For more information on this: http://www.growveg.com/growblogpost.a...

Posted by: Seed, Sow, Eat. (2 points) Seed, Sow, Eat.
Posted: August 20, 2015

Papaya always seems to have endemic mildew, even in LA (low humidity) in the direct sun. It'll be more extensive in the winter months, but I don't know any way to get rid of it completely (beyond antifungal sprays, which we haven't tried). We trim older leaves, avoid watering the leaves, and otherwise try to maintain hygiene, but just deal with it (sorry).

I'd note that for the most part the fungus seems to cause the plant no problems . It doesn't even seem to cause any problems for the plants around it - except I would be really cautious about planting them directly over other susceptible plants, like roses or squashes. Those seem to hate being stuck in a rain of mildew spores.

Another, more long term option, is I guess to plant a bunch of papayas, and cull the most susceptible ones.

Posted by: Brad Foley (1 point) Brad Foley
Posted: September 18, 2015

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