The pine spittlebug isn’t especially damaging to trees, in most cases, but is an interesting insect to run across. Host plants include Scotch pine, Austrian pine, white pine and all spruce and fir trees.
Spittlebug nymphs and adults suck sap from the tree and form a protective covering of froth around themselves. Unless they are exceptionally abundant on a tree, they seldom cause more than a discolored or slightly deformed branch tip. The worst problem is that Diplodia tip blight spores could invade a tree through spittlebug feeding wounds.
Spittlebug nymphs hatch in May from eggs laid under the bark of shoots. For the next six to seven weeks they feed on the tree’s sap and produce the characteristic, frothy spittle masses from partially digested sap. The spittle masses can be found on trees any time from May to early July.
After reaching adulthood in July they will still feed on the tree’s sap, but will no longer form spittle masses.
If there are an excessive number of spittlebugs on your tree they can be controlled with a foliar spray applied between mid-June through July.