Identifying Pine Needle Scale in Trees
Pine needle scale affects certain species of pine tree, particularly the Scotch pine, which is a popular choice of Christmas tree that is favored by tree farm producers. Pine needle scale can also grow on other types of pine, including the spruce, Douglas-fir and even red cedar. Despite the sound of the name, pine scale is actually a type of pest that uses the pine as both a food source and a place to reproduce. The white scale that gives this variety of insect its name is actually the egg sack.
While a tree doctor can inform you for certain of whether or not you have a pine needle scale infestation in your evergreens, there are ways that you can diagnose it yourself. The classic symptom of pine scale is the appearance of apple-seed shaped white growths on pine needles. Each individual scale is rather small, but they are visible to the naked eye. However, at a distance, you may not notice a minor outbreak of pine needle scale due to their small size. If you are not watching for pine needle scale, the first sign that it is present in young and maturing trees may be in the die off of clusters of needles or even branches. While older, mature trees are more resistant to die offs, a large-scale pandemic in a group of trees can kill its branches and needles as well.
As an infestation of pine needle scale grows, it becomes much easier to identify it even at a distance. As more scales are laid on the needles, the needles will turn pale and have a bumpy texture. In extreme cases, the scale will completely cover the needles, turning the foliage a blend of white, gray, and yellow. As the scales develop, yellowing is more common as the immature scales are this color. Adult females are a darker brown, and are much smaller than the white scales that are easily visible.
If your pine needle scale infestation grows to the point where the trees have turned these colors, a tree doctor may be able to help correct the problem with a use of natural predators and insecticides. However, due to the nature of white scale, insecticides are only useful at specific stages of the pine needle scale life cycle. Natural predators, especially the two-spotted ladybird, are able to eat white scale even when the egg armor is at its strongest.