Magnolias are deciduous, evergreen trees with broad, heavy, oval leaves that are glossy and dark green. They are prized for their beautiful flowers. There are several different species of magnolia, each with its own unique characteristics. For example, Magolia grandiflora, or the Southern magnolia, is perhaps the most widely recognized magnolia, known for its huge flowers. Magnolias suffer from a number of pests that feed on the leaves, wood, roots and flowers.
Aphids are known to attack magnolia trees, using their long mouth parts to tap into and suck the plant's fluids from the leaves and stems. Aphids are usually tiny with soft bodies and come in a range of colors from green to yellow to reddish brown. They often congregate together to feed. In large numbers, aphids can cause leaves to curl and die.
Scale insects of various kinds, including both armored and soft scales, feed on magnolias. In particular, the magnolia scale, one of the largest of the scale insects, prefers magnolias. Although unattractive, even heavy infestations of scale insects do not seem to affect the tree adversely. California armored scales, greedy scales, oleander scales, cottony cushion scales and tuliptree scales also feed on magnolia.
The magnolia borer is a pest that often affect young magnolia trees. It is the larval stage of a tiny beetle that lays its eggs on the trunk of magnolia trees. When the larvae hatch, they bore into the tree and feed, working their way down to the root system. The affected area of the tree appears sunken and spongy. If left untreated, magnolia borers can girdle and kill young trees.
Hoplia beetles feed on the blossoms of magnolias, among other trees. They cut round holes in the petals while feeding. They do not feed on the leaves. Hoplia is related to, and often mistaken for, the Japanese beetle.
Soft-bodied and wingless, mealybugs are tiny gray to white insects that have slightly segmented bodies covered in a waxy substance. They feed on the fluids of magnolia trees. Mealybugs are often found congregating together on the plant. Heavy infestations can lead to twigs dying, particularly in young plants. Many species of mealybugs feed on magnolia including Gill's mealybug and the obscure mealybug.
Thrips are tiny, moth-like insects with long bodies and feathery wings. They feed primarily on the flowers and buds of magnolia and can cause the flower buds to fail to open, if present in sufficient numbers. Greenhouse thrips, in particular, are often found on magnolias.
Tulip Poplar Weevil
This beetle has a long beak that it uses to punch holes in the leaves to feed. The larvae of the tulip poplar weevil live within the leaves, mining tunnels through them as they feed.