Yellow Spots in Auto. Help!

Hi! In the last two weeks my baby started to develop some yellow spots (pics included). First in the lower and older leaves, which died already, and now they are moving up. Before I take any steps I would love to hear your expert opinion.

Plant: Autoflowering in week 6 from germination, week one from flowering.
Medium: Growing indoor in soil with Miracle Gro Moisture Control Potting Mix.
Nutes: No nutes in the last three weeks. Before I did Schultz 10-15-10.
Other info: I had some flying bugs last week, which I handled with Diatomaceous earth and a No Pest strip.

Any feedback is welcomed!

Thanks!

Diatomaceous earth dust in your lungs is a long horrid death like TB which many doctors confuse, ... also the carcinogenic Dichlorvos (http://en.wikipedia.org/wiki/Dichlorvos) will drop you quicker than a .38 to the stomach ....lol

Always mix in 30-55% perlite to those hot mixes, avoids nute burn and compaction, best now to flush: https://www.rollitup.org/blogs/blog32237-flush-baby-flush.html

Thanks vostok! I am going to flush right now. I'll let you know how it goes!

Do you have any other advice?