Spittlebugs
Cercopidae & Aphrophoridae
also called Froghoppers, Cuckoo spit
Blobs of white froth on stems in early summer with a small green nymph inside. Almost entirely harmless — but the adult is a Xylella vector, which is why it is worth knowing.
How to know it
The froth is what you see: a wet blob of white bubbles the size of a thumbnail wedged where a leaf meets a stem. Part it and there is a soft, pale green wingless nymph 3–6 mm long inside. The adult is a small blunt-nosed brown hopper that jumps prodigiously and looks like a tiny frog.
What you'll see
- Blobs of white froth on stems and leaf joints from late spring, on lavender, rosemary, willow and many perennials.
- A soft green nymph inside each blob when you part the bubbles.
- Very slight distortion or wilting of the shoot immediately above a heavy cluster.
- On strawberry, several blobs on one plant and reduced fruit size.
- Small brown hoppers springing away from the foliage in late summer.
Where it comes from
Eggs overwinter in plant stems and litter and hatch in spring. The nymph inserts its mouthparts into the plant food-conducting tissue and whips the excess sap into froth around itself — the bubbles are a shelter from drying out and from predators. It feeds under the froth for several weeks, then emerges as an adult froghopper. One generation a year in most places.
Damp, sheltered gardens in late spring, on soft new growth. The froth is most obvious in May and June and is gone by midsummer.
Dealing with it
- Wash the froth off with a jet of water if the look bothers you; the nymph rarely re-establishes.
- Squash the nymph between finger and thumb where there are only a few.
- Do not spray. The damage does not justify it, and the froth protects the nymph from contact sprays anyway.
- Water and feed a strawberry planting carrying several nymphs per plant, which is the one case that costs a crop.
- Report unusual spittlebug numbers in a Xylella quarantine area, since the adult is the vector.
Keeping it out
- Cut perennial stems down in late autumn and clear the debris where the eggs overwinter.
- Keep lavender and rosemary pruned and open.
- Accept it. Cuckoo spit is one of the ordinary sights of early summer and almost never does harm.
- Encourage the birds and predatory bugs that take the adults.
- Watch for it on new nursery stock in areas where Xylella is regulated.
What it goes for
Lavender, rosemary, strawberry, chrysanthemum, rudbeckia, goldenrod, willow and most soft-stemmed perennials.
Trouble it brings with it
Who hunts it for you
- Garden birdsPasseriformes Both things are true: birds strip your currants and a brood of blue tits takes several thousand caterpillars out of one fruit tree in a fortnight. Net what you must and welcome them everywhere else — a nest box near the apples is worth more than a spray. Grow to recruit it: Echinacea,Elderberry,English holly,Goldenrod,Rudbeckia,Sunflower
- SpidersAraneae Webs, ambushes, and night patrols make spiders the garden’s steadiest generalist predators, taking whatever flies or crawls past. Mulch, ground cover, and undisturbed corners keep the population dense. Grow to recruit it: Lavender,Thyme
See also
The Cottage Garden Companion — the gardener's bestiary at cottagegardencompanion.com