NATURE FOCUS Cuckoo spit
DURING May through to July “cuckoo spit” starts to appear throughout the countryside and becomes particularly noticeable on the young stems and leaves of a range of many of our garden plants such as chrysanthemum, dahlia, fuchsia, lavender, rosemary, rose and willow.
These blobs of white frothy liquid appear in late spring, often coinciding with the arrival of cuckoos from Africa, hence its name.
This “spit” contains a nymph which is the immature stage of a froghopper, which are sap-sucking insects.
There are a number of different species of froghoppers that can be found in the UK, but the Common Froghopper Philaenus spumarius is the one that is most likely to be encountered in gardens.
These developing nymphs are up to 6mm in length and feed on plant sap.
They consume excess sap which is then blown out of their back-ends forming a stable froth concealing them from potential predators.
Plant growth is usually unaffected by these nymphs, but some distortion of the plant may occur if the nymph has been feeding at the shoot tips.
If their presence is felt to be unsightly, they can be wiped off by hand or dislodged with a jet of water from a garden hose, but it is better just to leave them undisturbed.
It is not necessary to use insecticides against froghoppers and unnecessary use of insecticides can unintentionally kill many beneficial insects and pollinators.
The adults are around 5 -7mm in length and hold their wings tent-like over their bodies.
They are extremely variably patterned in brown, black and white and are common and widespread throughout the UK.
Adults are on the wing from June to September.
Adult Common Froghoppers lay around 100-200 eggs on the host plant which then over winter with the nymphs emerging in the spring.
Unlike other insects, froghoppers have only three developmental stages; egg, nymph and adult, they omit the pupal stage that many other insects use to complete their metamorphosis.
Adult froghoppers, which also feed on sap move from plant to plant by jumping and some species can make vertical jumps of up to 70cm and accelerate at 4,000 metres per second experiencing over 400 G’s of acceleration.
They can jump over 100 times their length.
This is far more than can be tolerated by humans; highly trained fighter pilots wearing “G-suits” can only handle up to 8 or 9 G’s!
According to folklore it is possible to predict the type of summer that was ahead by checking the position in which the froghopper nymphs lay within their “cuckoo spit”.
If the insect is positioned with its head upwards then a dry summer is to be expected, but if downward then it would be a wet one. Cuckoo spit was also used as “folk cure” to remove and prevent warts, but there is no medical evidence of its effectiveness.
Look out for cuckoo spit in your gardens and the countryside and don’t disturb it unnecessarily as it provides a valuable food source for other animals such as frogs, birds and spiders.