Makudan

The Triarian Collective has sarcastically congratulated the Makudan on their "Brilliant internal security", "Exceptionally well controlled expansion" their "Excellent track record for mercy" and finally their "Certainly not overzealous and self destructive response". It isn't hard to notice the hypocrisy of the Triarian comments, considering the collective its self destroys entire ecosystems on a daily basis 

Colony 257

"Human Overlord Mclain.. When this is over we shall need to discuss the Draconian one of your ships was carrying." The overseer said over the communications, before tapping a few commands"Power up the energy projector again... Allow us to see how they well their seeds will work with Carbon Monoxide" He ordered, and the officer nodded
"Affirmative... Sir, EA bases detected under water. We can only destroy the ice caps" 
"Sufficent" he replied, and then the ship moved over the planets ice caps, firing the energy projector oj a low setting into it. The beam excited the atoms, breaking the bonds in the water as it melted to reduce it to its base components... The hydrogen exploded under the heat, and by the time the energy projector finished at each Ice mass, which was proportionate to the amount of water but took no longer than a few minutes, there was no water remaining and the land around it was irradiated and scorched to glass.
 released oxygen was also split under the heat, and bonded with the carbon that had been trapped below the worlds icecaps to form Carbon Monoxide. As anyone with even a rudimentary understanding of biology knows, with most organisms Carbon Monoxide tends to bind when used in respiration but refuse to unbind. This made is poisonous to many different creatures that relied on breathing.
Essentially, the Collective just tried to poison the air against the seeders as well,possibly starving the seeds...
On top of this they had put into action a chain of events by increasing the levels of greenhouse gases exponentially... The overseer knew that it would require terraforming to return the planet to normal after this, but he would rather have to reterraform the planet than watch it given to an enemy...
Of course, if this failed and he engaged Endgame, then everything on the planet would be obliterated... A climbing scale of destruction. He didn't want to do it if he could avoid it