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Southern Magnolia · Magnolia grandiflora

What are these pests on my Southern Magnolia?

Southern Magnolias are most commonly bothered by scale insects that hide along the stems. Check the branches for small, waxy bumps that do not move.

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pests on a plant
Photo: Jules Verne Times Two, CC BY-SA 4.0

Check these first

  1. Inspect the stems for small, immobile bumps.
  2. Check the leaves for sticky residue.
  3. Look for ants, which often farm scale insects.

Likely causes

  1. Scale Insects

    Most likely

    How to tell: You will see small, raised bumps on the twigs and undersides of leaves. The tree may also have sticky sap or black sooty mold on the leaves.

    What to do: Apply horticultural oil or neem oil to the branches during the dormant season. For active infestations, spray with insecticidal soap every 7 to 10 days.

  2. Aphids

    Possible

    How to tell: Tiny green or black insects cluster on new, tender growth. They cause leaves to curl and secrete sticky honeydew.

    What to do: Spray the affected areas with a strong stream of water to knock them off. If they persist, use insecticidal soap to manage the population.

Pests on other plants

Find out what's wrong with your southern magnolia

The list above covers the usual causes. Pocket Botanist looks at a photo of your actual plant and tells you the likely cause, how serious it is, and what to try first. Identification and a health check are free.

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When to worry

Small numbers of pests are usually manageable. Worry if you see branch dieback or if the tree looks stunted and sickly.

Stopping it coming back

Keep your tree healthy with proper water and light, as stressed trees are more attractive to pests. Monitor the branches closely in early spring.

Southern Magnolia: pests? Check yours with a photo

Every plant is a little different. Take a photo of your southern magnolia and Pocket Botanist tells you which cause is most likely, how serious it is, and what to try first. A few checks a day are free. Save the plant and you get care reminders timed for it.

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Questions people ask

Are scale insects hard to kill?
They have a hard outer shell that protects them, so timing is key. Treating them when they are in their crawler stage is most effective.
Will these pests kill my tree?
A severe, untreated infestation can weaken the tree over several years. Early detection and treatment prevent long term damage.

Guides to these causes

More problems with Southern Magnolia

Back to the Southern Magnolia guide

This article was generated with AI on from the plant’s care profile and is general information, not horticultural advice. Read about how we build these guides.