Pine needle scale is one of the most challenging and frustrating insect pest tree services have to deal with. These insects overwinter as reddish eggs beneath the white female scale covering. Fortunately, even when there is a light infestation of pine needle scale, it is easily recognized. The eggs will be hatching soon and the crawlers will move to new hosts or spread on existing hosts to feed and grow. The crawler stage of pine needle scale is reddish in color and can be easily seen with a hand lens. Another way to find out if your plant is infested is to shake a branch over a white sheet of paper, looking for small red dots. They look a lot like cayenne pepper. The spring generation will hatch over about a three week period. The second generation of pine needle scale crawlers will begin to appear in mid-July.

The key factors to controlling pine needle scale is timing of your plant spraying, getting good coverage when you spray infested plants, and using materials that will give good control of pine needle scale crawlers. Another option for controlling this insect is with a soil injection of an insecticide that can be absorbed into the vascular system of the infested plant. However, to be effective most soil injections need time to be fully absorbed by the host plant, so there is a delay between when the treatment is applied and when you will see any results.

Ideally, the initial tree or shrub spraying of plants infested with pine needle scale is done when 50 – 75% of the crawlers have hatched. Normally, this is about a week after the first hatch. In the Detroit, Flint and Port Huron areas this is normally between the middle to the end of May. If plants are heavily infested with pine needle scale a second spraying 10-14 days after the first treatment may be needed. Good coverage with the tree or shrub spraying is necessary for optimum control.

Finally, it’s important to choose an insecticide that is labeled to control pine needle scale. Also, if you have been using the same product multiple times it’s a good idea to switch to something with a different mode of action so you don’t build resistance in the scale population. Horticulture spray oil is effective against pine needle scale as a crawler spray for two to four weeks after peak crawler emergence.

To learn more about pine needle scale, and other scale insects, visit http://www.owentree.com/Scale_Insects.php