What’s Wrong with My Magnolia Tree?

Fuzzy looking ‘growths’ on the underside of magnolia indicate scale.

You may find some strange bumps on the branches of your magnolia tree. What are they? Sometimes they can be confused as buds, but they aren’t! If you touch them, they will feel firm, and you can pop them off with your fingernail. These are actually insects called scale.

Magnolia scale is one of many types of scale that affects trees. Typically, magnolia scale affects Saucer Magnolias and Star Magnolias.

How does this affect my tree?

Unfortunately, the scale insect damages trees by piercing and sucking the sap out of the plant with its mouthparts. Then the scale excretes a sticky substance called honeydew. Honeydew is the perfect place for different organisms to grow, like sooty mold fungi. Sooty mold will cause a blackish, stained appearance on branches. It doesn’t harm the plant, but it is unsightly. Both honeydew and sooty mold fungi can stain lawn furniture and attract wasps and ants.

So, what is the impact of scale on the magnolia tree? The scale feeding robs  the tree of energy. This stresses and slows the growth of the tree. When a tree is heavily infested, scale can eventually lead to tree thinning and eventual death.

Blackish staining on a leaf from sooty mold

How does scale start?

The life cycle of magnolia scale is quite simple. The scale over winters as nymphs on the branches of the tree. These nymphs begin feeding in spring and mature in early summer. The females lay eggs that hatch into “crawlers”. These crawlers then set themselves up on branches and begin feeding.  At this mature stage, they no longer are mobile. To manage this insect, it is important to provide specific, timed treatments depending on the life cycle of the insect. Wachtel Tree Science utilizes treatments timed to impact  the most vulnerable stage to maximize the effectiveness of treatments. Depending on the time of the year, soil systemic insecticides, dormant oils in the spring or insecticide sprays in late summer, we will utilize the right treatment for the most effective results against this pest.

Magnolia scale is a difficult pest to control. It is important to talk with your arborist to take the first steps to get scale under control and to keep it under control. Wachtel Tree Science provides an all-around approach to keep your magnolia trees healthy and beautiful.

Find my Arborist

The tree planting crew was courteous and professional as always. The arborist who did the insect control took the time to protect our bench under the tree. We appreciated that the arborist took the time to cover the metal bench beneath the tree before spraying.

​Mary K. – Brookfield, WI

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