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Extension Toxicology Network

A Pesticide Information Project of Cooperative Extension Offices of Cornell University, Michigan State University, Oregon State University, and University of California at Davis. Major support and funding was provided by the USDA/Extension Service/National Agricultural Pesticide Impact Assessment Program.


Publication Date: 9/93


Trade names of this product are Ryanodine and Ryanicide.


Ryania is a botanical insecticide made from the ground stems of Ryania speciosa, a native plant of tropical America. The principle alkaloid in this stem extract is ryanodine which makes up 0.16-0.2% of the product. Ryania is highly toxic to the fruit moth, coddling moth and corn earworm, European corn borer, and citrus thrips, but it is ineffective against the cabbage maggot, cauliflower worms or boll weevil.

Ryania is a general use pesticide.



Ryania has a very low toxicity to mammals and is labeled with the CAUTION signal word. At high doses it affects muscles, preventing contractions and resulting in paralysis (9). Symptoms of poisoning include vomiting, weakness and diarrhea. Rigidity of the muscles and depression of the central nervous system can lead to a coma and to death.

The rat oral LD50 is 1,200 mg/kg and guinea pigs have an oral LD50 of 2,500 mg/kg and rabbits have 650 mg/kg LD50. Dogs are much more susceptible with an LD50 of 150 mg/kg. The estimated lowest lethal dose for man is 143 mg/kg. The pure ryanodine alkaloid is 500 to 700 times more toxic than the crude powder. A 2-5 mg/kg dose of ryanodine elicited symptoms in the frog and mouse (4). The dermal LD50 for rats is above 2,000 mg/kg. No information is available on inhalation toxicity.


Rats and guinea pigs were fed diets containing 1% ryania powder for at least six months and showed no symptoms. Rats fed 5% diets had weight loss and some deaths within 25 days (4).

Reproductive Effects

No data was available.

Organ Toxicity

Large doses of ryania powder (around 1,500 mg/kg/day) in the diets of rats produced hemorrhages in the pancreas and intestines. It also produced lung complications in the test animals (10).

Fate in Humans and Animals

Single sublethal doses given directly into the vein produced slowly developing high blood pressure in experimental animals (1). Residues of 6 ppm on apples were harmless to laboratory animals.


Chickens fed for six months on diets of 1% ryania showed no symptoms and did not have any evidence of cumulative effects (4). Ryania is moderately toxic to birds and wildfowl. Some LD50 values include: wild birds 1.78 mg/kg; pigeons 2.31 mg/kg; and quail 13.3 mg/kg (8). It is considered moderately toxic to fish also. The 96-hour LC50 for rainbow trout is 3.2 mg/l and 18.5 mg/l for bluegill.


The toxicologically active portion of ryania, ryanodine, is water soluble but stable during storage and stable upon exposure to light. Ryanodine is not considered to be poisonous to plants (4).

The major degradation product of ryanodine is anhydroxyanodine (6).


Progressive Agri-Systems
201 Center St
Stockertown, PA 18083
Telephone: 215/759-5911

Review by Basic Manufacturer:

Comments solicited: May, 1992
Comments received:


  1. Gosselin, R.E., R.P. Smith and H.C. Hodge. 1984. Clinical Toxicology of Commercial Products, Williams and Wilkins, Baltimore, MD.
  2. Spencer, E.Y. 1981. Guide to the Chemicals Used in Crop Protection. Research Branch, Agriculture Canada, Canadian Government Publishing Centre, Ottawa, Canada.
  3. Johnson, W.W. and M.T. Finley. 1980. Handbook of Acute Toxicity of Chemicals to Fish and Aquatic Invertebrates. U.S. Dept of the Interior, Fish and Wildlife Service, Resource Publication 137.
  4. Negherbon, William O. 1959. Handbook of Toxicology, Volume III: Insecticides, A Compendium. Div of Biology and Agriculture, National Academy of Sciences, National Research Council, W. B. Saunders Company, Philadelphia, PA.
  5. Windholz, Martha. (ed.). 1976. The Merck Index, An Encyclopedia of Chemicals and Drugs. Merck and Co., Inc., Rahway, NJ.
  6. Crosby, D.R., Chairman. 1966. Natural Pest Control Agents, Advances in Chemistry Series 53. American Chemical Society, Washington, DC.
  7. Washington State University. 1988. Northwest Pesticide Label Information Retrieval System, Cooperative Extension, Pullman, WA.
  8. National Institute for Occupational Safety and Health 1985-86. Registry of Toxic Effects of Chemical Substances, U.S. Dept of Health and Human Services, Centers for Disease Control.
  9. Ware, George W. 1986. Fundamentals of Pesticides: A self Instruction Guide. 2nd Edition. Thomson Publications. Fresno, CA.
  10. Kuna, Samuel and Ralph E. Heal. 1948. Toxicological and Pharmacological Studies on the Powdered Stem of Ryania Speciosa, A plant insecticide. Journal of Pharmacology and Experimantal Therapeutics. Vol 93:407-413.