Foam on your plants? It’s probably froghoppers – Here’s what you need to know

While you are out and about in your garden this month you will have most likely encountered blobs of bubbly foam on a wide range of herbaceous plants, often referred to as ‘Cuckoo Spit’. While the arrival of said bubbly foam blobs coincides with the arrival of migratory Cuckoos each year, they are not actually the ‘spit’ of Cuckoos, or any other saliva-producing animal for that matter. In fact, it is created by juvenile Froghoppers, a Hemipteran, sap-sucking group of insects that are closely related to leafhoppers, planthoppers and aphids.

Froghoppers (also known as Spittlebugs) are common insects throughout the British Isles, and 10 native species can be found. During spring, the Froghopper’s eggs (which will have been laid on plant stems during autumn), hatch into small pale green nymphs, that are almost immobile. To protect themselves from predation and desiccation, the nymphs create a blob of foam to live within, by mixing expelled air into the waste fluids that they excrete whilst feeding on their host plant’s sap.

The species that’s most often seen in Britain’s gardens will be the Meadow froghopper Philaenus spumarius, and by mid-Summer, these nymphs will have matured and vacate their frothy blobs as robust and highly mobile adults.