Sap Suckers and Magnolia Trees

Magnolia trees are susceptible to different sap sucking insects.

Magnolia trees have beautiful spring flowers and are well known in the South. Unfortunately, these trees are susceptible to several pests that suck out their sap and cause a lot of damage, even to the point of tree death.

Types

Aphids are small pear-shaped insects that are common pests on most trees, including magnolias and typically attack only new growth. Armored scales have flattened coverings over their body and attack only weakened trees. Spider mites are small insects that are hard to see with the naked eye but are oval-shaped and green, green-yellow or brown in color.

Symptoms

Leaf distortion, wilting, leaf drop, and secretions of honeydew follow an infestation of aphids. Large infestations, and thus large amounts of honeydew, can cause sooty mold. Armored scales cause wilted, yellow leaves and leaf drop, as well as bark that will crack and exude a gum-like substance. They can kill young trees if infestation is severe. Damage from spider mites starts off as a peppering of dots on leaves and, if continued, turns the leaves yellow.

Treatment

Aphids, spider mites and armored scales all have natural enemies in ladybugs, minute pirate bugs and parasitic wasps. If introduced to your garden, they can help control infestation. For large infestation, insecticides can be used.

References

• University of California Agriculture and Natural Resources: Scales
• University of Florida Department of Entomology and Nematology: Twospotted Spider Mite
• University of Missouri Extension: Aphids, Scales and Mites On Home Garden and Landscape Plants