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You are here: NRS Home / Research Programs / Forest Disturbance Processes / Invasive Species / Hemlock Woolly Adelgid / Control and Management / Biological Control / Scymnus coniferarum: Predator of Hemlock Adelgids in Western North America
Hemlock Woolly Adelgid

Scymnus coniferarum: Predator of Hemlock Adelgids in Western North America

Research Issue

[photo:] Scymnus (Pullus) coniferarum Crotch 1874, the conifer lady beetle.The lady beetle, Scymnus (Pullus) coniferarum Crotch 1874 is native to the western United States and previously known to be associated with adelgids on pine trees in California.  Adults of S. coniferarum were discovered on western hemlock in the Seattle, WA, area in 2009. Research was conducted to (1) evaluate its potential as a biological control of the hemlock woolly adelgid (HWA) in the eastern United States, (2) establish if it could safely be released into eastern hemlock forests and (3) develop methods to establish and evaluate its efficacy as a biolocgical conrol of HWA

Research Results

Research was conducted both in the laboratory and in its native habitat to obtain more information on the biology and host range of S. coniferarum. In its native habitat (Seattle, WA area), comparisons were made to Laricobius nigrinus, a predator of HWA that has been introduced previously as a biological control of HWA. These two predators are partially segregrated by habitat and phenology--Scymnus coniferarum was more prevalent on hemlocks exposed to sun and wind and its larvae and were abundant in late May and June, after the larvae of L. nigrinus had stopped feeding and moved to the soil for pupation. In the laboratory, S. coniferarum has been reared from egg to adult on HWA, and it is relatively easy to maintain a colony on HWA. Host range choice tests indicate that S. coniferarum is specific to adelgids. This species is very similar in appearance to Scymnus (Pullus) suturalis Thunberg, a native of Europe that is established in the eastern half of the U. S.  Based on information on the biology, efficacy and safety of Scymnus coniferarum, an environmental assessment was prepared and a permit was granted for its release in eastern forests (http://www.aphis.usda.gov/plant_health/ea/downloads/HWA-biocontrol-EA-FONSI.pdf). Further work is underway in Virginia, North Carolina, Georgia, and Tennesse to rear and establish this lady beetle for biological control of HWA.

Montgomery, Michael E.; McAvoy, Thomas J.; Salom, Scott J. 2011. Other species considered. In: Onken, B.; Reardon, R. eds. Implementation and status of biological control of the hemlock woolly adelgid. FHTET-2011-04. Morgantown, WV: U.S. Department of Agriculture, Forest Service Forest Health Technology Enterprise Team: 116-122. Chapter 10.

Montgomery, Michael E.; McDonald, Richard C. 2011. Notes on the biology of Scymnus (Pullus) coniferarum: an adelgid predator. In: McManus, Katherine A; Gottschalk, Kurt W., eds. 2010. Proceedings. 21st U.S. Department of Agriculture interagency research forum on invasive species 2010; 2010 January 12-15; Annapolis, MD. Gen. Tech. Rep. NRS-P-75. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station: 108.

Montgomery, Michael E.; McDonald, Richard; Schwartzberg, Laura. 2009. Scymnus (Pullus) coniferarum (Coleoptera: Coccinellidae): an adelgid predator native to the western United States. In: McManus, Katherine A; Gottschalk, Kurt W., eds. Proceedings. 20th U.S. Department of Agriculture interagency research forum on invasive species 2009; 2009 January 13-16; Annapolis, MD. Gen. Tech. Rep. NRS-P-51. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station: 89.

Montgomery, M. E.; Lyon, S. M. 1995. Natural enemies of adelgids in North America: their prospect for biological control of Adelges tsugae (Homoptera: Adelgidae), In: Salom, S. M. ; Tigner, T. C.; Reardon, R. C., eds. Proceedings of the First Hemlock Woolly Adelgid Review, Charlottesville, Virginia, 1995 Oct. 12; Morgantown, WV. U.S. Department of Agriculture, Forest Service, Forest Health Technology Enterprise Team: 89-102.

Lyon, S.; M., Montgomery, M. E. 1995. Scymnus (Pullus) suturalis Thunberg (Coleoptera: Coccinellidae): new locality records and a report on feeding on hemlock woolly adelgid, Adelges tsugae Annand (Homoptera: Adelgidae). The Coleopterists Bulletin. 49(2): 118.

Research Participants


Principal Investigator

Research Partners

  • Scott Salom and Molly Darr, Virginia Tech, Blacksburg, VA
  • Richard McDonald, Symbiont, Sugar Grove, NC

More Information

  • Melody Keena, Research Entomologist, U.S. Forest Service, Northern Research Station

Last Modified: 05/08/2015

About this Research Area

Science theme: Forest Disturbance Processes

Science Topic: Invasive Species


About Hemlock Woolly Adelgid
Biological Control
Featured Publication

Montgomery, Michael E.; McDonald, Richard; Schwartzberg, Laura. 2009. Scymnus (Pullus) coniferarum (Coleoptera: Coccinellidae): an adelgid predator native to the western United States. In: McManus, Katherine A; Gottschalk, Kurt W., eds. Proceedings. 20th U.S. Department of Agriculture interagency research forum on invasive species 2009; 2009 January 13-16; Annapolis, MD. Gen. Tech. Rep. NRS-P-51. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station: 89.