unusual Pilea problem

[maga]

Hi,
I have a 5 year old Pilea. It's been developing black blotches/spider webs at the back of its leaves (I think it started about 2 months ago). The leaves don't drop, just develop more and more of these webs. I'm pretty sure it's not a pest problem. I thought perhaps fungus and sprayed it with a mixture of baking soda and neem oil (3 times every 5 days) but it hasn't helped. Has anyone seen something similar and knows how I can save my plant?
Thanks

 

[Marck]

Greetings, welcome to the Forums.

Chinese Money Plant (Pilea peperomioides), in the Nettle Family (Urticaceae), is a most attractive house plant, that is easy to grow and propagate. It also does well in garden settings in mild climates. It's distinctive perfoliate leaves do indeed resemble those of some species of Peperomia, though the two genera are not at all closely related, with Peperomia being in the Black Pepper Family (Piperaceae).
Pilea peperomioides is native to southern China.

I am not certain what is causing the black spots on the leaves. It may be a type of sooty mold fungus. Do the spots form on new growth or older leaves? Did the problem get better or worse during summer?