My Phlox plants are having red bugs all over -- each plant has these little...
Thank you for the question. It looks like your phlox has aphids. Aphids are about 1/8 inch long and come in many colors, including the color I see in the photo. They suck sap from plants with a fine needle like stylet and can transmit viral diseases to plants as well.
Control can be as simple as using a spray of water from the hose to knock them off, and some people have purchased lacewing larvae and lady beetles from an internet site to be released in hopes of biological control.
There are chemicals you can use as well, but always read package directions and follow them exactly.
Read more about them and control options here: http://www.extension.umn.edu/garden/insects/find/aphids-in-home-gardens/
Thank you for contacting Extension.