Problem with pine tree

Asked September 30, 2020, 10:31 AM EDT

I have pine needles turning brown in certain sections and some type of growth on the branches (see pics). Does it have a disease and can it be treated?

Washtenaw County Michigan

1 Response

Your pictures are of a spruce tree rather than a pine, probably a Norway or white spruce. The brown formations shown in your first and third pictures are called "galls," and are created by a tiny insect called a Eastern Spruce Gall adelgid. In heavy infestations, or after years of repeated infestation, the host tree will have the appearance of dying from the perimeter inward. Extended infestations can greatly weaken the host to a point where secondary attackers (insects and diseases) can then successfully colonize and perhaps even kill the host.

Over-wintering immature females can be found at the base of the buds on the host plant. In the early spring, they resume development and produce eggs about the time of budbreak. These eggs hatch in about ten days and the immatures begin to feed on the new needles. This feeding stimulates gall formation, which surrounds the nymphs. New galls will almost appear to be normal green growth but only close inspection, at this time will reveal the abnormality. By late August, these galls will dry, crack open and the immature adelgids will emerge and mature into winged, egg-laying females. The eggs, usually found on the needles, will hatch in late summer and the nymphs will settle down at the base of the new buds on healthy shoots.

Galls dry and open in late August into October. Once galls have started to form there is virtually no management strategy aside from pruning them out; however, to do this effectively usually requires the removal of too much foliage which disfigures the tree.

The links below gives information on this pest and offers a control strategies.