Houndstongue (Cynoglossum officinale) is a flowering plant that is a member of the Borage family. It is a biennial that produces a rosette the first year of growth and bolts and flowers during the summer of the second year. C. officinale has a strong mousy-type smell, or of roasted peanuts. The flowers are small, arranged in clusters and not showy. C. officinale prefers well drained, relatively sandy and gravelly soils. It can also be found in shady areas and especially under the canopy of forests and wetter grasslands.
Houndstongue Toxic Components
C. officinale contains four types of pyrrolizidine alkaloids---cynoglossine, consolidine, echinatine and heliosupine. Ingestion of pyrrolizidine alkaloids causes liver damage and eventually liver failure. Substantial ingestion results in inhibition of neurons and paralysis. Most poisonings occur due to ingestion of C. officinale in contaminated hay or feed. C. officinale is more likely to contaminate hay at the time in which it is most toxic, when it is young and actively growing. The toxicity varies considerably, ranging from 5 to 360 mg/kg body weight per day of dried plant.
- Depression
- Weight Loss
- Jaundice
- Diarrhea
- Photosensitivity
- Lethargy
- Transient Elevations Of Serum Enzymes And Bile Acids
PHYSICAL CONTROL: Once established, houndstongue quickly forms dense monocultures. Treat first year plants with herbicides. Mow bolted plants to eliminate seed production. Repeat this process for several years to exhaust the seed bank. It is imperative to establish a healthy population of native perennials on treated areas to prevent the re-establishment of houndstongue or other noxious weeds.
CHEMICAL: First-year houndstongue rosettes are easily controlled with 2,4-D applied from late May o mid-June. Second-year plants are much less susceptible to 2,4-D.
BIOLOGICAL: A root weevil, Mogulones cruciger, has been released for control of houndstongue in Canada.
- Momayyezi, Mina, and Mahesh K. Upadhyaya Influence of Soil Moisture Stress on Vegetative Growth and Mycorrhizal Colonization in Hound's-tongue (Cynoglossum officinale) Weed Science . 2017.
- Swearingen, J., C. Bargeron Invasive Plant Atlas of the United States University of Georgia Center for Invasive Species and Ecosystem Health. 2016.
- Early Detection & Distribution Mapping System Available online at http://www.eddmaps.org/; last accessed August 5, 2014. The University of Georgia - Center for Invasive Species and Ecosystem Health.. 2014.
- Cynoglossum officinale, hound’s tongue Poison Garden Blog. 2013.
- Petzinger E. [Pyrrolizidine alkaloids and seneciosis in farm animals. Part 1: occurrence, chemistry and toxicology]. Tierarztl Prax Ausg G Grosstiere Nutztiere. 2011.
- Zentek J, Aboling S, Kamphues J. [Accident report: animal nutrition in veterinary medicine--actual cases: houndstongue (Cynoglossum officinale) in pasture--a health hazard for horses]. Dtsch Tierarztl Wochenschr.. 1999.
- Stegelmeier BL, Gardner DR, James LF, Molyneux RJ. Pyrrole detection and the pathologic progression of Cynoglossum officinale (houndstongue) poisoning in horses Journal of Veterinary Diagnostic Investigation. 1996.
- Pfister, J. A.; Molyneux, R. J.; Baker, D. C. Pyrrolizidine alkaloid content of houndstongue (Cynoglossum officinale L.). J Range Manag, 45(3), 254-256. 1992.
- Pearson EG. Liver failure attributable to pyrrolizidine alkaloid toxicosis and associated with inspiratory dyspnea in ponies: three cases (1982-1988). Journal of American Veterinary Medicine Association. 1991.
- Baker DC, Smart RA, Ralphs M, Molyneux RJ. Hounds-tongue (Cynoglossum officinale) poisoning in a calf Journal of American Veterinary Medicine Association. 1989.
- Knight AP, Kimberling CV, Stermitz FR, Roby MR Cynoglossum officinale (hounds-tongue)--a cause of pyrrolizidine alkaloid poisoning in horses Journal of American Veterinary Medicine Association. 1984.