Feeding injury caused by Four-lined plant bug is showing up on Shasta daisies, Gentiana and other perennials. Retail customers may confuse the damage with disease. Feeding damage appears as spotting on the upper leaf surface. The adult is greenish yellow with 4 black lines running down the back and about 1/4 in long. The immature stage is bright red or orange with black spots on the segment behind the head. As they mature, a yellow stripe appears on each side of the wing pads. They feed for about 6 weeks and plants often outgrow the damage. Plant bugs move rapidly and try to hide out of sight when disturbed. Depending on the plant, the spotting on leaves may be dark or light to dark tan. The spots are caused by plant bugs feeding on the plant juices and injecting a toxin when feeding. Susceptible plants include Heuchera, Dahlia, Chrysanthemum, Rudbeckia, Heliopsis, Lavandula, Lupinus, Paeonia, Coreopsis, Liatris, Gentiana and Geranium.
Tina Smith, UMass Extension
