Plant Doctor Archive

Pohutukawa with curly leaves

I have several pohutukawa plants in pots awaiting for some wetter weather to plant out on the coast of the Wairarapa, but they appear to have curly leaf. Why has this happened and how can I treat it?

From the damage described, your pohutukawa is being attacked by psyllids (the 'p' is silent), also known as chermids. Psyllids are small insects about the size of aphids. The nymph stage can be mistaken for scale insect; the adult looks like a winged aphid. On some plants, psyllids do little damage. Mature pohutukawa are not attacked, only the soft young growth.

The soft young shoots of pohutukawa, pittosporums and eugenia are a delicacy to young psyllids. They cause leaf distortion, tips die back and a sooty mould can appear. The sooty mould is caused by a fungus living on the honeydew excreted from the insects and will disappear as soon as the insects are controlled.

The nymph has a scale-like covering that acts as a shield that is hard for insecticides to penetrate. Spray your plants with Orthene which is a systemic insecticide and effective on hard-to-control insect pests such as psyllids. Add Conqueror Oil to get better control.

Alternatively, use an insecticide such as Target mixed with Conqueror Oil to help the spray make contact with the insect. Established pohutukawa are usually not affected by psyllids.

Advice by Dr Dan Blanchon from Unitec's Diploma in Sustainable Horticulture and Bachelor of Resource Management.

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