Insect Blog

Pitch Mass Borer

May 14th, 2019

Plants Affected:

Pinyon pines.


Flesh colored globs of sap or “pitch masses” can be seen oozing out of the main stem and, in severe cases, out of individual branches.  As the severity of the infestation increases the tree will gradually decline in vigor and foliage will then out.  Individual branches may die.  The entire tree may eventually die.

Life Cycle:

The insect known as the pitch mass borer is thought to be an infestation of two different borers that have different life cycles.  Although research is underway there has been no final determination as to what species these borers are.


Chemical treatments are not effective.  Because these borers attack stressed trees it is important to keep them healthy with general care practices.  Pinyon pines are a dryland species of pine that will only tolerate small amounts of water.  Practices such as planting away from lawn areas, moving rain spouts away from the trees, and otherwise decreasing the water they receive are the single most important factor needed to prevent the borers.  When infestations become severe the borers can be dug out but this should be a last resort practice due to additional wounding of the tree that occurs when they are removed.  It is also very time consuming and expensive.