I'm wondering what's causing the leaves of my morning glories to turn yellow and develop black/brown patches, along with what looks to be like white mold, as shown in this photo:

Several cotyledon leaves have turned yellow, formed black spots, and appear to have white mold growth.

This is worse in the cotyledon leaves, but I did notice some true leaves having these as well, as shown here:

A true leaf of morning glory with black spots and possible white mold.

Something else I have noticed is that a couple of vine ends have turned brown. Also, some of the leaves that are not yellow do not look very healthy. Specifically, they appear bumpy with a very slight yellow-green tinge - not bright green and smooth. Both of these characteristics are shown in this photo:

A vine that turned brown at the end, in front of a leaf that appears unhealthy - bumpy and very slightly yellow-green.

Finally, I found some of these bugs hovering around the soil. They look like fungus gnats:

Bug hovering around morning glory soil - front view. Bug hovering around morning glory soil - side view

If this is correct, then I'm wondering if my plants have a fungal disease, as I read that fungus gnats can spread these diseases. But I'm not sure what disease this is. I have always kept these plants outdoors and for now, I just trimmed off the bad leaves. Does anyone have any ideas of what it might be, and how to treat it?

This summer was my first time trying to plant morning glories from seeds. This is already my third try (the other two times I had some kind of pest eating up the plants). It has not been easy! Any advice is greatly appreciated.

  • 1
    Morning glory gets most of the same diseases as sweet potato, look up sweet potato diseases. Commented Aug 23, 2020 at 2:39
  • @PolypipeWrangler Thank you! That's useful to know. The spreading seemed to have slowed down a lot lately. I used some diatomaceous earth to get rid of the bugs and I have not seen any more. But the weather has been a lot cooler also. Maybe that has helped alleviate the problem.
    – JoshuaTree
    Commented Aug 26, 2020 at 19:57


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