Four-lined Plant Bug
There are polka dots on my plants!
The Four-Lined Plant Bug, Poecilocapsus lineatus, has both a nymph stage and an adult stage. It only has one generation per season, which does help cut down on how much damage it does. The nymphs feed from late April through May, then find a mate, lay eggs, and die off. The eggs overwinter until the following spring when they hatch into nymphs then grow into the adult insect after about 30 days. It is the nymphs that do the most damage to plants, sucking moisture out from the underside of leaves. As adults, they use mouthparts to inject digestive liquid into the leaf, then suck the nutrient rich juices from the leaves of your plants, leaving the pock-marked and shriveled.
You’ll first notice uniform circular patches of damage on plant leaves. These circles then turn dark brown, giving the leaves a scorched appearance. While they often frequent aromatic herbs like mint, oregano, sage and sweet marjoram, basil and thyme, they will also damage some ornamental annuals and perennials. If you have shasta daisy in your garden you’ll often find them a spring-time target of the four-lined plant bug.
While the leaf damage they cause looks pretty bad, it’s not long lasting and plants typically outgrow the damage. Simple applications of insecticidal soap or neem oil can help minimize the infestation and subsequent damage.