What Is Cuckoo Spit?

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

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.

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.