What's eating my downy serviceberry?

Downy Serviceberry fruit is intensely sought by birds — virtually the entire crop can disappear within days of ripening. Spider mites stress foliage in hot, dry summers. Borers attack stressed trunks. Forest tent caterpillars and fall webworm can defoliate branches. Wildlife including deer and rabbits browse young trees in winter.

Entire crop of small red-purple fruit taken by robins, cedar waxwings, and many other species at peak ripeness. Net small trees; larger specimens are difficult to fully protect — plant a surplus if the goal is harvest; growing near the house reduces some bird pressure.

Fine stippling on leaves; bronzed or yellowed foliage in dry summers; fine webbing on leaf undersides. Maintain adequate irrigation; blast mites off with water; apply horticultural oil or insecticidal soap if infestation is heavy.

Mass defoliation in outbreak years; silken mats on branches; entire canopy stripped. Remove egg masses in winter; apply Bt (Bacillus thuringiensis) at early larval stage; for small trees, hand-remove caterpillars.

Larvae bore into the trunk base; frass and sap flow at entry holes; gradual dieback of the whole tree. Wrap trunk base with wire mesh; keep base free of mulch touching bark; prune and destroy any infested wood.