The Eurondans began to be disgusted from seeing the Breeders breed like a plague across the planet, which prevented the "genetic purity" the Eurondans wanted. As a result, the Eurondans created plans to eradicate the Breeders forever.
The Eurondans began to poison the atmosphere of their homeworld in order to eradicate the Breeders, but the Breeders managed to survive underground, just like Eurondans were. The Eurondans had built a massive underground complex before the war began in order to be able to house themselves and continue their plans to try to eradicate the Breeders.
The two nations began to manufacture aero-fighters and unmanned vehicles, and their World War lasted for several decades. Eventually, the Eurondans found out their enemies had survived the poisoning of their world. In 2000 the Breeders were winning the war, as the Eurondans had begun to run out of resources, such as Deuterium (heavy water), which was required for their defence field generator. In desperation, the Eurondans attempted a last defence with their fleet of aero-fighters. As they had control of the stargate, they approached Earth to ask for help, and SG-1 provided some much needed fuel, which almost allowed the Eurondans to win the war. However, SG-1 discovered the truth and decided to help the Breeders rather than the Eurondans in winning the war. The Breeders managed to break through the Eurondans' air defences and bomb their bunker, which led to the bunker being destroyed and all the Eurondans dying. Thus, the Breeders had won the war. (SG1: "The Other Side")