Hi there. I have a fern garden in Toronto with about 5 varieties of ferns. I have what appears to be an infestation of a small, brown bug or parasite that anchors to the underside of the leaf. It seems to prefer my red stemmed ferns. It is so prolific and symmetrical that it almost looks like part of the leaf! I have done some research on-line and gather that a) I should treat it asap as ferns are prone to infestations and b) ferns are very sensitive to insecticides. Help!
Those are called "sori", (plural for sorus) where the spores are made on ferns. That would be a fertile frond. Some ferns are identified by the sori becaue many ferns look so similar.
http://en.wikipedia.org/wiki/Sorus
I always thought ferns were pretty tough, as long as their water and light requirements are met. Just don't fertilize them.
Guess they are norm and don't harm the plant.
It's just the reproductive part of the fern, no need to worry.
