On the left living Aphids on pepper plants. Aphid cocoons and a close up of aphids husks.One winged adult Aphid in the center and belowTwo empty Aphid husks with exit holes
On the right two Aphidius wasps surveying a host of parasitized Aphid. A Red pepper acts as a colorful background.
An ecosystem at my fingertips. Live aphids, Aphid coccoons, and four Aphidius wasps. all in a space barely larger than my thumb!
The Aphidius wasps appeared spontaneously on pepper plants I'm trying to overwinter in my heated basement. The Aphids increase quickly and as such are a concern. I am seeing an enormous increase in numbers of the Aphidius wasps. Will they over take the Aphids, only time will tell. The pepper plants look much worse for the wear though

There are many suppliers of the Aphidius wasp on the internet. Here are two sources with additional information
They can easily appear spontaneously too as mine did. They seem to work great in the low light situation of my walk-in basement.
They are of course harmless and it's amazing to see them flitting from leaf to leaf!