The breeding of C. reticulatus is a thing that really attracts my attention. It is strange that one of the most attractive corys is not bred in captivity. In fact, I read a book article about a successful breeding of C. reticulatus, probably taken from a German magazine in early 80's. I think that reports about 375 eggs in reticulatus - that you can find in some descriptions in the internet - come from the same source. But I have never read any other reliable report since. Actually, I found one: some German claims that his reticulatus spawn regularly in his tank, but he was not able to raise any fry. He explicitly states that "the breeding of C. reticulatus shouldn't be particularly difficult, even for a beginner (!)".
http://www.dooyoo.de/tiere/netz-panzerwels/1010724/
But the fact is that reports about breeding this attractive fish are almost non-existent. The problem with such claims is that under the name "Corydoras reticulatus" there are often exported absolutely different fish. From some reason, especially species from the delphax-ambiacus group are honoured by reticulatus name.