It was a good point. All this time, Korra was thinking of something they could fight, like the spiders. She hadn't even considered the problem might be something they could fight in the traditional sense.

"You mean like some kind of...sickness," Korra said slowly, considering the idea. The tree didn't seem ill to her, but she had also never seen it before. "It makes sense. Sometimes you can't fight off a cold, no matter how strong you are physically."