This foam has appeared on my bottlebrushes, and only on the bottlebrushes – it is not on any other plant in the garden. Is it some sort of egg receptacle?
J.Z., Mt Clear.
Your photos show the froth made by a spittle bug, a tiny green nymph that sucks sap. It is the juvenile stage of an insect known as the froghopper.
The bubbly froth protects it from both desiccation and predation.
The froth is sometimes known as “cuckoo spit”, an old English name that arose because it appears in spring about the same time as the cuckoo.
It is more common on wattles than it is on bottlebrushes, and it can be common at the base of fog grass in springtime.
It is generally considered to be harmless to most plants.
The froghopper is a native insect. There are several different species.
- Questions and photos are welcome. Send to Roger Thomas at The Courier, PO Box 21, Ballarat, 3353, or email to firstname.lastname@example.org