The other day my daughter and I were checking the milkweed plants for monarch caterpillars and eggs. We try to do this periodically, just to see whats happening. The plants are looking pretty good at this point, considering that they all started from self sowed seeds this year.
Instead of any signs of morarchs we found these little guys...
Do you see them? They are called Oleander Aphids or Milkweed Aphids and probably originated in the Mediterranean region, where principal host plant, oleander is native. These creepy looking yellow and black aphids can be found on the new growth of oleander, butterfly weed and milkweed. They almost look unreal with their yellow bodies and black legs.
So what's a Plant Geek to do with such an infestation? Well, we typically use a hard stream of water to knock those guys right off the plant. You can also squish them (yuck!) or use an insecticidal soap to get rid of them. You'll always want to check for caterpillars or monarch eggs first and make sure you don't harm them.
You definitely don't want to use a pesticide since these chemicals would also harm the butterflies you are trying to attract. In the majority of cases they won't kill the plant, so you can always choose to just live with them, like we did on this particular day.