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The most obvious symptom of a southern pine beetle infestation is the
discoloration of the needles in the tree's crown. They will fade from
green to dull green, yellowish, and finally reddish-brown before falling.
This needle fade can be easily seen from the ground or the air.
Crown discoloration is just one sign of beetle intrusion. As the
beetles enter the tree along the entire trunk, small light yellow to white pitch
tubes will usually form. These masses of pitch are about the shape and
color of popcorn and similar in size. In areas where the trees are
especially weak, pitch tubes may not be formed. Instead, a collection of
reddish boring dust can be found in the bark crevices or cobwebs along the base
of a tree.
Pitch
Tubes
Boring Dust
Two other traces of evidence that the southern pine beetle leaves behind are
the winding "S"-shaped egg galleries in the cambium as well a
blue-stain fungus that the adult beetles introduce. Along with the
girdling effect of gallery excavation, the fungus contributes to the death of
the tree by eventually plugging the water conducting tissues.
Pine with blue-stain fungus infection
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