These are called four-lined plant bugs and they feed on many types of herbaceous plants. The good news is that there is only one generation of these per year. You could hand pick and drop into soapy water the ones that you see, and/or use an insecticidal soap or horticultural oil on the nymphs. They are difficult to control, however, because you need to apply the treatment directly to the bugs. Most plants will grow out of the damage as the season progresses.

Here is additional information about them:

• https://extension.umd.edu/hgic/plant-bugs-flowers
• http://entnemdept.ufl.edu/creatures/veg/leaf/Poecilocapsus_lineatus.htm

CKC