Pine Needle Scale Crawlers Emerging Soon

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It’s not just baby birds that hatch from eggs each spring. In the next several weeks, pine needle scale crawlers will emerge across North Carolina after overwintering as eggs.

A close-up of teardrop-shaped scales covered in a white waxy covering

Pine needle scale uses piercing-sucking mouthparts to retrieve nutrients from the tree. Image: Tim Tigner, Virginia Department of Forestry, Bugwood.org.

Pine needle scale (Chionaspis pinifoliae) is a scale insect native to North America. They feed on pine needles with piercing-sucking mouthparts, retrieving nutrients and causing yellowing of needles. Usually, they are minor pests in natural forests. However, in managed pine stands, pine needle scale can be problematic because heavy feeding reduces needle length and tree growth. Severe infestations, although not common and typically associated with other tree health stressors, can cause branch dieback or even kill young trees.

Pine needle scale are sessile, meaning once they start feeding, they don’t move. This stationary lifestyle makes them susceptible to many natural enemies which attack the scale and therefore, management is often not warranted. Generally, proper tree care to increase tree vigor helps to reduce scale populations. In problem areas, heavily infested branches should be pruned out and in some cases, pesticides can be applied. Horticultural oils and soaps are recommended as these will not impact the natural enemies that play a key role in reducing scale populations.

Images show heavy and light infestations of pine needle scale on pine needles.

Pine needle scale infestations are often reduced naturally by natural enemies and extreme cold winter temperatures. However, heavy infestations can occur and management in managed pine stands might be needed to reduce damage. Images: USDA Forest Service – Region 4, Bugwood.org (left); Kelly Oten (right).

Why do we need to know crawlers are emerging soon? Simply put, crawlers are the susceptible life stage for pesticide treatments. As the name suggests, crawlers crawl around, searching for a feeding site. After finding a site and settling down, they secrete a white, waxy covering over their bodies which protects them from many things, including pesticide applications. Crawlers lack this covering, therefore, horticultural oils and soaps should be applied while crawlers are active.

Within the week (by April 10), crawlers are expected to emerge in the southern third of the state, from the Sandhills to the Alligator River areas. One to two weeks later, emergence is expected across the piedmont and lower elevation mountains. To scout for crawlers, one can tap or beat an infested branch over a white piece of paper. Crawlers should be knocked free and begin crawling across the paper if they are present.

A map of the US, showing areas warming up where pine needle scale will be emerging soon.

The National Phenology Network predicts pine needle scale emergence across North Carolina in April 202

Written By

Kelly Oten, N.C. Cooperative ExtensionDr. Kelly OtenAssistant Professor and Extension Specialist in Forest Health Call Dr. Kelly Email Dr. Kelly Forestry & Environmental Resources
NC State Extension, NC State University
Posted on Apr 5, 2021
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