Orange Creamsicle x Hella Jelly Humboldt

So this tent is a trip. Things were so good for so long and just like that, boom. My other cultivar in the tent hermed. Like all of them. None of these girls hermed so don't worry. What I am worried about is how much they were seeded. I don't see any development and they are almost done but still not happy with what happened. Now this week one of the girls got aphids! I'm still not sure how long they've been there since it's only the middle plant, which was moved to the front right. I defoliated the shit out of it. Taking off any leaf that had them. There werent a lot but believe it or not this is my first time having bugs. Lucky or not I tried to remove them all. They didn't really effect the others. My question to all of you: how would aphids only get to the middle plant in a grow like this? Pretty confused how that happened and didn't start on an outer plant.