I'm seeing the occasional whitefly on tomatoes and eggplants (no clusters, just one here, one there). I'm not familiar with them at all. Do I need to worry about seeing the occasional one, or only get concerned if I see an infestation? Right now I'm more or less ignoring them.

On the good bug front, sweat flies (syrphids) all over the place. I actually saw one laying eggs on my chervil flowers that have black aphids on them. Hahahaha! Enjoy those aphids, sweat fly larva.