I had the same think happen but it did it with my pepper plants I am growing outside. Here is what I read, but not sure if you can put on these plants or not. I would wait til some one else confirms this but here is what i read what to do for my pepper plants.
I'm thrilled to hear about your wonderful germination percents. I get a lot of satisfaction when I hear glowing reports like yours. My pesticide of choice is to mix 1 teaspoon of dishsoap in a large spray bottle and apply directly to plants and try to get a direct hit on the bugs. The dishsoap is biodegradable and will stick to the plant and linger until you get a rain.
Here's how it works. Soft bodied insects basically breathe through their skin and it suffocates them. With hard bodied insects it gives them a deadly case of dysentery. It works on most insects...very effective on Aphids...and is non toxic to your plants. By the way, it is the Ants that kinda 'Herd' the aphids. They carry them up the plants so the aphids can suck the sap out of the leaves. Then those smart lil' ants 'Milk' the aphids...much as we do with cows. Ants hate citrus rinds...particularly oranges. So make a mix of your leftover citrus peels in the blender with some water and put at the base of the plants. It won't kill the ants but usually they will move on.