Magnolia Scale: A Silent Threat To Your Beloved Trees

Magnolia trees, cherished for their stunning flowers and glossy leaves, face a formidable foe in the form of the magnolia scale (Neolecanium cornuparvum). This pest, one of the largest scale insects in North America, can wreak havoc on your prized magnolia plants if left untreated.

What Is Magnolia Scale

Magnolia scale is a sap-sucking insect that affects all magnolia species found in Michigan. These insect pests attach themselves to branches and stems and use their needle-like mouthparts to feed on the plant's sap, gradually weakening the plant over time.

Adult stage Magnolia scale. | Whitney Cranshaw, Colorado State Univ., Bugwood.org

Magnolia Scale Life Cycle

Knowing the life cycle of magnolia scale is the key to controlling this insect:

Egg Stage: In summer to early fall female scale insects produce hundreds of eggs beneath their protective waxy covering.

Crawler Stage: This is the most vulnerable phase, when newly hatched nymphs move to find feeding sites.

Nymph Stage: Nymphs settle, begin feeding, and start to develop their own protective coating.

Adult Stage: By late spring nymphs mature into adults. Females grow larger and produce a thick, waxy coating, making them hard to control with foliar sprays.

Signs Of Magnolia Scale Infestation

• White, powdery coating on branches

• Sticky substance (honeydew) on leaves and branches

• Black, sooty mold growth

• Yellowing leaves and branch dieback

Impact On Magnolia Plants

Magnolia scale can severely affect plant health:

• Sap loss weakens the plant, leading to stunted growth

• Honeydew promotes sooty mold growth, reducing photosynthesis

• Increased vulnerability to other insect pests and diseases

Treatment Options For Magnolia Scale

Effective management by Owen Tree requires a multi-faceted approach:

Cultural Controls: Proper tree care, including regular watering, fertilizing and pruning.

Biological Controls: Encourage natural predators like lady beetles.

Chemical Controls: Targeted insecticides applied at the right time in the pest's life cycle

Early detection by our ISA Certified Arborists and prompt action is the key to protecting your magnolia plants from this persistent pest. Regular inspections and proper tree care can go a long way in maintaining the continued health and beauty of your magnolia plants.