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Pinon "pitch mass" borer |
By Carl Wilson, Horticulturist, Denver Cooperative Extension
The pinon pitch mass borer is a serious pest of pinon in landscape plantings throughout
much of Colorado. Though pinon is the main host, ponderosa and possibly Scots and Austrian
pines may occasionally be infested.
Boring larvae gouge the tree's water conducting vessels causing large quantities of
pinkish pitch to ooze. Damage can be seen on trunks and large branches. Wounding
disfigures and weakens the tree. Heavily infested branches may even break.
Like most borers, pitch mass borer takes advantage of already weakened trees. In
landscapes, overirrigation and overcrowding are stresses identified as factors in borer
attack. Adjusting irrigation schedules and thinning overcrowded plantings should be
considered important parts of any control efforts.
Homeowners can attempt to puncture and kill individual borers with a flexible wire. Note
that larvae can be difficult to find as they often tunnel for several inches under the
bark. Moth crystals containing paradichlorobenzene (PDB crystals), may be inserted into
borer pitch masses to fumigate larvae.
Preventive trunk sprays can reduce attacks. Registered products containing pyrethroids or cygon sprayed to coat trunks and major branches during the June to August flight period of the adult moth help prevent additional boring. Two or more treatments per season should be repeated for at least two years.
Photograph of Pinon Pitch-Mass courtesy of Judy Sedbrook.
