Mint and other herbs generally should be pest free, so it really “bugs” me when I find something has been eating them. The damage seems worse than usual this year, perhaps because of the cool, damp spring. It’s only this week that I figured out what makes those annoying black dots on the upper leaves of my peppermint, as well as on the lemon balm and sage.
Some internet sleuthing got me to the answer – “four-lined plant bug”. I’d never heard of it before, and I had never caught it in action until I knew what to look for. It’s a small bug, about the size of a striped cucumber beetle, and depending on its stage, has yellow and black stripes with orange or red coloring as well. It feeds on leaf tissue, leaving spots and holes, sometimes causing leaves to shrivel up. The good news is that the bug only goes through one life cycle each summer; the damage to the plant is finite and mainly aesthetic. There is not much one can do for management beyond cleaning up leaves and stems at the end of the season, so there is no place for them to overwinter. I will just continue to snip and discard the affected plants, and in the fall cut back and clear the bed more carefully.