Cuckoo spit

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.

Willow froghopper (Aphrophora alni) on Willow (Salix sp.). Credit: RHS/Entomology.

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
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What is cuckoo spit?

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

Symptoms

  • Blobs of white frothy liquid develop on young stems and leaves of a range of plants 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

  • 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
  • There is no need to use an insecticide against froghoppers

Biology

  • 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 noticeable damage
  • Overwintering eggs are deposited in plant stems in late summer

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