They will simply re-initiate below the previous cut. If you have been caught up in the hustle of the spring and failed to get some woody plants installed, don't think it is necessary to wait until late summer or next spring. A suggestion I would like to make for those who are considering adding or replacing some shrubs in the landscape this year is to consider some viburnums. They should be used more often than they are because of their hardiness and resistance to diseases and environmental stresses. Although all pines and spruces in North Dakota are susceptible to pine needle scale, mugo pine and Black Hills spruce are most often affected by this insect pest in our state.
Many infestations begin on the lower branches.
The scales feed on sap, causing spotting of needles. Premature needle loss may occur when infestations are heavy. Severe infestations left unchecked can cause branches or even entire trees to die. A waxy coating, which is impenetrable to most pesticides, is secreted as the insect feeds and grows. As the female lays eggs late into October, she will shrink and the underside of the scale will fill with overwintering eggs.