Mugwort is invasive, causes allergies, and is probably the single most-common street weed growing in NYC. So probably not a huge problem for the aphids to kill

Mugwort is invasive, causes allergies, and is probably the single most-common street weed growing in NYC. So probably not a huge problem for the aphids to kill as much as they can. The cooler story about aphids though is the dancing wooly aphids, which should be starting to colonize beech trees right around now. In addition to dancing when you shake the tree, there is an entire species of fungus that grows only in the honeydew left by the aphids. These are the black masses that you see on pretty much every single beech tree: https://en.wikipedia.org/wiki/Scorias_spongiosa https://en.wikipedia.org/wiki/Scorias_spongiosa https://www.youtube.com/watch?v=9k_FuYrMeDw https://www.youtube.com/watch?v=9k_FuYrMeDw Fortunately they don't harm the beech trees, esp. since they're mycorrhizal with chanterelles and black trumpets.