One of my African Violets has been showing signs of blight. I transplanted it several months ago to a larger pot, but now realize I didn’t do enough to prepare its long neck of a stem for the move. According to The Bump/How to Transplant African Violets with Long Necks, I should have removed some of the outer brown tissue from the stem before burying it in the potting soil.
Added to the long neck syndrome and dying leaves was the growth of yellow mushrooms in the soil. Mushroom Appreciation has a very informative article on yellow mushrooms in potting soil. The problem is quite common and won’t hurt your plant, but the mushrooms are toxic and if you have pets or small children you should replace the soil or toss the plant.
“Leucocoprinus birnbaumii (also known as Lepiota lutea) is quite common in potted plants and greenhouses. This species is considered inedible, although the exact toxicity is unknown. So don’t eat them, no matter how candy-like they appear!” ~ Mushroom Appreciation
Since my plant was failing to thrive I opted to discard it. I will watch for mushrooms in my remaining houseplants and scrape the top layer of soil away if the problem recurs.