If cooler weather persists all spring, hatching can continue for a month or more. Newly hatched scales are called crawlers. They are minute in size, a similar rosy-purple color as the eggs, and somewhat resemble tiny aphids. This is the only active period in the life cycle of the pine-needle scale. Individual crawlers move about for hours to days before inserting their mouthparts into the needles.
Populations can be active for up to three weeks.
At higher elevations, pine-needle scale produces only one generation per year. However, at lower elevations a second generation is common in mid- to late summer. Because egg hatch may be extended, a distinct second generation does not always occur. These later-emerging young primarily settle on the current season needles. Several natural enemies are associated with pine-needle scale colonies in Colorado.