Many gardeners across the eastern two-thirds of the U.S. and southern Canada will start to notice damage from four lined plant bugs (Poecilocapsus lineatus) over the next few weeks. Appearing as tiny, round, sunken pockmarks on the foliage of such plants as forsythia, viburniums, Shasta daisies, lavender, oregano, geraniums, sage, mums, basil, peonies, mint, and many others, the damage is as distinctive as the insect itself.
All about four lined plant bugs:
This true bug measures a quarter-inch in length at maturity, and both looks and acts like a little speed demon. Four black longitudinal “racing stripes” grace the otherwise electric yellow-green wing covers of the adults (see feature photo). And with the ability to scuttle beneath foliage in a flash, these little buggers are difficult to spot and nearly impossible to capture.
Four lined plant bugs overwinter as eggs inserted into plant stems. Tiny, reddish-orange and black rounded nymphs (see picture below) hatch in early spring and pass through five growth stages over the course of four to six weeks. As the young nymphs feed, little damage is evident, but as they reach maturity, you’ll start to notice the distinctive pockmarks they leave behind. Damage from the adult bugs is usually spotted in late May through June and perhaps into early July.
Fortunately, the adults feed for only one month before “finding love”, laying eggs, and then biting the dust. There is only one generation per year. Because the feeding period of the four lined plant bug is so brief – and the damage is largely aesthetic – control measures are seldom warranted, though insecticidal soap, horticultural oil, and neem oil are moderately successful against them.
In my own garden, I don’t bother trying to control four lined plant bugs with any products. I simply prune or pinch off spoiled plant growth in early July, when the insects are gone. This encourages the growth of new foliage that will remain unaffected by this insect for the rest of the season.
Have you spotted four lined plant bugs in your garden?