Pine Needle Scale Diagnostic Guide
Pine needle scale, Chionaspis pinifoliae, is a conspicuous and common armored scale insect on conifers throughout the United States. Pine needle scales appear as oyster shell-shaped white blisters on the needles of conifers, often so numerous they envelop the entire needle. Although they prefer pines, they are known pests of spruce, fir, and Douglas fir causing disfiguration and often death of the infested needles and general decline of the whole tree.
Trees at Risk
Pine needle scale attacks pines (especially Mugo and Scots pine), fir, spruce, and douglas fir.
Signs of Damage
- Sickly, yellow appearing needles.
- Heavily infested trees can appear silvery from a distance.
- Thin or weak appearing canopies as infested needles are shed.
- Oyster shell shaped white blisters on the needles of conifers, the adults are white, grayish white and are 1/8 inch long.
- Pine needle scale envelops the entire needle.
- Presence of numerous, oval shaped white insects on needles.
- First generation eggs hatch over 2-3 weeks in mid-spring (April/May). Second generation eggs hatch over 2-3 weeks in mid-summer (June/July).
- Crawlers move to the previous year’s needles to insert their mouthparts through the stoma to feed; upon which they begin to form new armor.
- 3-5 weeks later the males emerge as winged adults. Females emerge as wingless adults.
- After mating, the females grow for a couple more weeks and lay 20-60 deep reddish colored eggs under the armor.
- Eggs overwinter under the armor of the adult scale.
- Two generations per year.
Pine needle scale is an armored scale that can have two generations per year. Insecticide applications must be timed to ensure trees are protected prior to when nymphs insert their mouthparts into the needles and begin to feed. Apply Transtect™ to the soil or as a systemic basal bark spray in the spring prior to crawler emergence. Transtect™ soil applications and systemic basal sprays have provided good results on leaf feeding armored scales such as False Oleander Scale, Pine Needle Scale and Elongate Hemlock Scale.
Systemic Bark Spray using Transtect
Dosage: 6 pkt/gal of water. Apply 1.5 - 2.0 fl oz of mixed solution/in of DBH. Timing: Apply Transtect 1-2 weeks prior to egg hatch and crawler emergence at 277 GDD in the spring of the year. Spray the lower 5-6 feet of the trunk evenly. Re-Treatment: Annual
Foliar Spray using Up-Star Gold
Dosage: 21.7 fl oz/100 gal water Timing: Apply 1st treatment of Up Star Gold® or as 1st generation crawlers are emerging at 277 GDD and reapply for 2nd generation crawlers at 1350 GDD. Re-Treatment: Two treatments per year and repeat annually
Foliar Spray using Distance
Dosage: 8 - 12 fl oz/100 gal water + 0.5 - 1.0% Hort Oil Timing: Apply 1st treatment of Distance® + Hort. Oil as 1st generation crawlers are emerging at 277 GDD and reapply for 2nd generation crawlers at 1350 GDD. Re-Treatment: Two treatments per year and repeat annually
Transtect™ soil applications or basal systemic barks sprays have performed extremely well in trials on pine needle scale.
A Diagnostic Guide is designed to help you identify a pest issue and management solutions. Always refer to product label for all rates and approved uses. Some images courtesy forestryimages.org. Use of the images does not imply endorsement of treatments by forestryimages.org