Plant Doctor Archive

White secretions on Grevillea

There is a white, waxy secretion coming from my grevillea. Is this a sign that my plant is about to die?

This is one of the symptoms of psyllids — an insect that looks a bit like an aphid — which grevilleas are prone to. Other symptoms include damaged flowers, distorted yellow leaves, and buds that shrivel and fall to the ground.

Psyllids attack and lay their eggs on the young leaves, but they are not actually harmful to the plant itself. The white wax you describe is a crystalline sugar which the psyllids excrete.

Prune off minor damage. Spot spray with a soapy spray, pyrethrum or a simple oil spray if necessary.

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

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