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Cuckoo spit

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last updated Apr 2, 2013
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Willow froghopper (Aphrophora alni) on Willow (Salix sp.). Credit: RHS/Entomology.

Cuckoo spit begins to appear in late spring at a time when the familiar call of cuckoos can be heard, but otherwise has no connection with the bird.

What is cuckoo spit? Back to top

Cuckoo spit is a white frothy liquid secreted by the immature nymphs of a sap-sucking insect known as a froghopper.

Symptoms Back to top

  • Blobs of white frothy liquid develop on young stems and leaves in late spring and summer
  • Each blob contains a creamy white insect nymph up to 4-6mm (¼in) long
  • Usually plant growth is unaffected, but, if the nymph has been feeding at the shoot tip, this may cause some distorted growth

Control Back to top

  • Apart from producing the 'spit' these insects have little detrimental effect on plants and can be tolerated
  • If considered unsightly, they can be wiped off by hand or dislodged with a jet of water from a garden hose
  • It is not worth using an insecticide against froghoppers

Biology Back to top

  • This froth has no connection with cuckoos
  • It is secreted by the immature stages of sap-sucking insects known as froghoppers, presumably as a means of protecting themselves against predators
  • The adult insects are present during mid-late summer and live openly on  plants. They do not produce cuckoo spit or cause any noticable damage
  • Overwintering eggs are deposited in plant stems in late summer

Quick facts

Common name Cuckoo spit, caused by froghopper nymphs
Scientific names Various species but mainly Philaenus spumarius
Plants affected Many plants, including chrysanthemum, dahlia, fuchsia, lavender, rosemary, rose and willow
Main symptoms Blobs of white frothy liquid form on plant stems. A small pale insect lives inside the froth
Most active May-July