Class five Deathworlders have Problems dealing with a planet which Flora contains a mysterious Plant (Wink Wink).
For them it is as deadly as Arsenic is for us.
Their reaction when Humans Line Up to colonise it -- Anon Guest
[AN: Going with convergent evolution because the chances of weed happening exactly as it happened on Earth, on another planet, are astronomical at best]
Things had been going badly for the latest J'krog colony. The world, verdant and unclaimed, had promised a plethora of food for their rising numbers, including the plant life. It promised such and lied. Vast numbers of warriors and young were falling sick and dying. Exposed skin blistered, burned, and went necrotic in rapid succession. Something on this plentiful planet was highly toxic to the J'krog.
J'krog were made to gather and hunt. Farming and science were not their strong suits. Their species more or less stumbled into space travel through a series of fortuitous accidents. Therefore, they sent out a call for help. There was no shame in seeking allies when the enemy could get past one's defences. It had taken the J'krog some centuries to learn that particular lesson.
The Humans were the one to answer the call with their curiosity and powerful investigatory tools. They soon found that the abundant plant life had chemicals they called 'cannabinoids', after one of their Terran plants that hosted most of the entire gamut as its defence strategies. The J'krog, whose homeworld hadn't come up with the poison, were naturally undefended from it. Allergic, in fact.