Episode 56 of The Trigan Empire
The Green Fog
aka The Dryaks
The Green Smog (The Collection)
De groene plaag (Dutch title)
The Green Plague (Dutch title, translated)
Written by Mike Butterworth
Illustrated by Don Lawrence
The Green Fog was originally published in 8 instalments in issues 732 (24 January 1976) to 739 (13 March 1976) of Look and Learn magazine.
It is reprinted in Volume 12 of The Trigan Empire—The Collection (the Don Lawrence Collection).
It is reprinted in Volume 5 of The Rise and Fall of the Trigan Empire (Rebellion).
Plot summary (Dutch)
MediaFire via British Comics Compilations