Lilly Pilly Problems, Pests, and Diseases (Scale, Leaves Curling)

Common Lilly Pilly issues include white scale and leaves dropping, curling, or turning yellow.

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Lilly Pillies are hardy plants that are native to Australia. They’re commonly grown as hedges and make perfect screening plants.

Although these plants are quite tough, there are certain problems, pests and diseases that you may come across. 

In this article, we discuss these in detail and give you some suggestions on how to fix them.

Lilly Pilly branches dying or Lilly Pilly dropping leaves 

If some of the branches on your Lilly Pilly are dying or you notice the leaves dropping off, it could be due to a number of reasons.

A slow die back could be caused by a variety of pests like borers or curl grub. 

On the other hand, if your plants are quite young and exposed to full sun, the leaves may be sun burnt. Provide some afternoon shade if this is the case.

Treatments

  • Check the plant for evidence of pests. Borers will leave small holes in the branches and you’ll see some sawdust around them. Unfortunately, there’s no control that you can use for this except to cut back the affected branches.
  • Check for curl grub in the soil around the roots. These are small white caterpillar-like grubs that live in the ground and will feed on the roots of your plant. When the roots are damaged, it can cause die back on some of the branches and the dropping of leaves. You can control these grubs by dousing the soil with a solution of neem oil and water.

White scale on Lilly Pillies

White scale is a common garden pest that can affect your Lilly Pillies. This type of scale has a white waxy coating and you’ll usually see it on both the stems and leaves.

If your plant has been affected by white scale, you may also notice some black mould on the plant and ants crawling all over it.

The black mould is a result of the honeydew that the scale secretes and the ants are eating this.

Treatment

White scale can be difficult to get rid of, so you have to be persistent in your efforts to control it. 

The best time to treat your plant for white scale is in late spring and early summer. You need to thoroughly spray the pests with something like white oil or any other type of oil-based pesticide. Follow the initial treatment with another spray 10 to 14 days later. 

If you notice white scale on your plants in winter, you can rub them off with your fingers while wearing a pair of rubber gloves. Try to remove as many of the adult scale as you can.

Lilly Pilly leaves being eaten

If you notice that your Lilly Pilly leaves are being eaten, the culprit is most likely the Paropsides calypso beetle also known is the Lilly Pilly beetle.

These beetles are bright green in colour and look somewhat similar to a ladybug. You might also notice the pale green larvae grubs on your plant.

Both the beetles and the larvae will feed on the leaves of your plant. These grubs will pupate over winter in the soil under the plant.

Treatment

The grubs can easily be picked off by hand if there are only a few. You might also want to have a look at the soil around the base of your plant to find any larvae that haven’t emerged yet and remove them.

Additionally, you can spray your Lilly Pilly with a mixture of neem oil and water to help control these pests.

Lilly Pilly leaves curling

If the leaves on your Lilly Pilly hedge are curling or they look like they have bumps or blisters on them, this is caused by Eugenia psyllids.

These are sap sucking insects and the pimples that you see are a result of the newly hatched larvae feeding on the foliage. These insects also excrete tiny white pellets that can result in sooty mould.

Treatment

If the damage is severe, the best thing that you can do is just prune off the damaged branches and then spray your plant with white oil. You should also treat your plant with a systemic insecticide containing Imidacloprid

Lilly Pilly leaves turning yellow

If your Lilly Pilly leaves are turning yellow, it could be caused by overwatering, a nutrient deficiency or a pest infestation.

Overwatering can cause root rot and this is generally fatal for your plant, which is why good drainage is essential for Lilly Pillies. However, nutrient deficiencies and pest problems can easily be fixed.

A healthy Lilly Pilly requires soil that is moist, but not wet or soggy.

Treatment

First, you want to ensure that your Lilly Pilly hedge is not living in waterlogged soil with poor drainage.

If root rot has already infected your plant, there’s nothing you can do to save it. You should be able to see evidence of the rot on the trunk at the base of the plant. 

  • For nutrient deficiencies, make sure you feed your Lilly Pillies with a balanced fertiliser in early spring. Repeat the fertiliser application once again in late summer. Dynamic Lifter is a good all-round fertiliser suitable for Lilly Pillies.
  • Most pests are relatively easy to control with white oil or a solution of neem oil mixed with water.

Lilly Pilly black leaves

If you see some of your Lilly Pilly leaves turning black, you likely have a sooty mould problem. This is usually caused by the excretion of sap sucking insects.

Treatment

Spray your tree with white oil or a mixture of neem oil and water to control the insect pests that are causing the sooty mould on your foliage.

FAQ

Does myrtle rust affect Lilly Pillies?

Yes, myrtle rust affects plants in the Myrtaceae family, which includes gum trees, guava, tea trees, bottle brush, and Lilly Pilly. Myrtle rust, also known as guava rust, is a fungal disease and is a new disease in Australia. It favours environments with cool temperatures and high humidity.

Can you overwater a Lilly Pilly?

Lilly Pillies do not respond well to overwatering and it can cause root rot in the plant. When planting a Lilly Pilly, water it every day for the first couple of weeks and then as needed after that. The best way to know whether your plant needs watering is by testing the soil moisture, either using your finger or a soil moisture meter. The soil around a healthy Lilly Pilly should feel moist but not wet or soggy.

Photo of author

Annette Hird

Annette Hird has an Associate Diploma of Applied Science in Horticulture. She has worked in a variety of production nurseries, primarily as a propagator. She also had the responsibility of a large homestead garden that included lawn care, fruit trees, roses and many other ornamental plants. More recently, Annette has concentrated on improving the garden landscape of the homes that she has lived in and focused a lot of energy on growing edible plants as well. She now enjoys sharing her experience and knowledge with others by writing articles about all facets of gardening and growing plants.