Hi Melinda,

I'm sorry you're dealing with this. I've had four-lined plant bug in my own garden, and they're a nuisance. Usually that's all they are -- most perennials outgrow the damage when the bugs' season ends in July.

Using chemicals that kill adult four-lined plant bugs can also kill beneficial insects. When these bugs are adults, they're hard to target with insecticide because they dart under leaves or drop to the ground when you approach.

The best time to kill these bugs is when they're in their red immature stage (one is in your photo) and are susceptible to insecticidal soaps, which kill on contact and won't affect other good bugs. 

So if you can tolerate the damage, do so. Part of having a pollinator garden is riding the pest roller coaster and trying to let nature balance things out. My own experience is that these bugs are bad some years and not so bad in others. My main preventive is to cut down the perennials they like in the fall, because their eggs are laid in the stems of perennials like bee balm, mint, ironweed and echinops. Remove those fallen stems and get them off your property. This has helped a lot in my garden.

Next May, start watching for the immature red bugs and use insecticidal soap on them. Spray first thing in the morning or at dusk to avoid burning the plants when rays of sun hit wet leaves.

Should you choose to spray now, look for an insecticide labelled for four-lined plant bug. Spray at dusk when bees and other pollinators are not active.

Here's more information:

https://extension.umn.edu/yard-and-garden-insects/four-lined-plant-bugs

Hope this helps.

You’re welcome, Melinda. It’s hard to be restrained when responding to something like this (I’m speaking from experience) but it pays off in the long run with a healthier garden. After that one very, very bad year with these guys I decided to limit my response to cutting down their favorite hosts in the fall and since then they’ve been just a nuisance. I think the garden has become a balanced environment where maybe other bugs or birds are preying on them. Nature often balances things out.

Good luck!