Common Parasites on a Photinia Hedge

Aphids and Scales

• Aphids and scale insects attack photinias by piercing their leaves and sucking out the juices. They also excrete sticky honeydew. Aphids can be found on the leaves and stems. They are black, brown, green, red or yellow, pear-shaped insects. Light infestations will not cause serious damage but heavy infestations may cause the leaves to yellow and stunt new shoots. Armored scales and soft scales are tiny, flat insects that are usually white but can be many different colors. A heavy infestation will cause the shrub to appear water stressed. Armored scales can kill entire shrubs but soft scales do not cause that much damage. Aphids can usually by controlled by simply washing them off the hedge with a strong spray of water and scales normally can be tolerated by photinias without treatment. If the infestation is severe, however, spray the bugs with insecticidal soap. It is usually sold in ready-to-use spray bottles. The soap must coat the bugs to kill them. Be sure to spray the undersides of leaves and branch corners.

Lace Bugs and Thrips

• Lace bugs and greenhouse thrips pierce the leaves and feed on the juice or tissue cells. Young lace bugs do not have wings but the adults do. They may have dark or pale coloring but all species have a clear, lacy coating. Greenhouse thrips are tiny black insects with light wings. These insects and their eggs can be found on the undersides of the leaves. They rarely cause serious damage but the leaves they feed on will have stippling and appear bleached. Healthy photinia hedges are not usually seriously harmed but, if the infestation is severe, they can be killed with insecticidal soap just like aphids and scales.

Boring Beetles

• Bark beetles and flatheaded borers tunnel into the woody stems of photinias. Bark beetles are small black, brown or red insects that are nearly the size of rice. They eat through the inner layer of bark and lay their eggs within the wood. The adults emerge from the stem, leaving a pattern of tiny holes. There may be a moist, sappy area and sawdust at the point of infestation. Flatheaded borers usually attack shrub stems that have been weakened by injury or sunburn. Females lay their eggs in bark crevices and the young feed on the inner layers of bark. Adult borers are small, flattened oval, black, blue, copper or green beetles with a metallic sheen. The larvae are pale and wider at one end. There may be a moist area on the bark or rough texture at the point of infestation. They may kill stems or even the entire shrub. There is not much that can be done to eliminate these beetles and borers. Prune out infested stems and keep the hedge healthy. Do maintenance pruning during the winter while the beetles and borers are dormant and do not stack wood near the hedge.

Leaf-eating Beetles

• Black vine weevils and fuller rose beetles eat the flowers, leaves and roots of photinias. Black vine weevils are black beetles with antennae and a long snout. Fuller rose beetles are brown with a long snout. Neither of them fly. The adults eat the leaves and flowers while the larvae eat the roots. Adult feeding does not cause serious harm but the black vine weevil larvae can weaken or kill the shrub. Healthy hedges should not be seriously harmed by them. Pick the adults off and destroy them. Place a 6-inch wide band of sticky material along the ground around the stems and trim back the branches of nearby trees so the beetles cannot easily cross over to the hedge.