Black locust-Robinia pseudoacacia L.-Poisonous plant

Black locust

General poisoning notes:

Black locust (Robinia pseudoacacia) is a naturalized shrub or tree that is planted as an ornamental in warmer parts of Canada. The seeds, bark, and leaves contain toxic proteins that have caused sickness and death in cattle, horses, poultry, sheep, and humans. The plant should be considered toxic to all animals if ingested. Children were poisoned (with rare reports of fatalities) after chewing on plant material, especially the bark. This tree can be found around older farms and houses and is also planted along fencerows. Children should be taught not to ingest any parts of the plant. If older trees are cut down in areas where livestock have access, make sure that the animals do not ingest any sprout (sucker) growth that may emerge from the stump (Hansen 1924, Kingsbury 1964, Cooper and Johnson 1984).

Nomenclature:

Scientific Name: Robinia pseudoacacia L.

Vernacular name(s): black locust

Scientific family name: Leguminosae

Vernacular family name: pea

Geographic Information

British Columbia, Nova Scotia, Ontario, Prince Edward Island, Quebec.

Toxic parts:

Bark, leaves, seeds

Notes on Toxic plant chemicals:

Robin (or robinin) and phasin, which are toxic proteins called toxalbumins, are present in black locust. A glycoprotein that agglutinates red blood cells has been extracted from the plant. It is not clear if this is robin or another substance. Experimental feeding to horses has shown the following toxicities:

=> aqueous extract of bark about 0.1% of body weight caused symptoms

=> powdered bark about 0.04% of body weight caused symptoms

The poisonous principle appears to be about one-tenth as toxic to cattle (Kingsbury 1964, Cooper and Johnson 1984).

Toxic plant chemicals:

phasin
robin(in)

Animals/Human Poisoning:

Note: When an animal is listed without additional information, the literature (as of 1993) contained no detailed explanation.

Cattle

General symptoms of poisoning:

Anorexia, death, dyspnea, nausea, paralysis, posterior, weakness.

Notes on poisoning:

Cattle that ingested the sprouts and leaves of black locust were poisoned. Experiments show that cattle are 10 times less sensitive to the toxin than horses. Symptoms include anorexia, weakness, posterior paralysis, nausea, coldness of the extremities, and dilation of the pupils. Death occurs in severe cases (Hansen 1924, Kingsbury 1964).

Horses

General symptoms of poisoning:

Anorexia, death, nausea, paralysis, posterior, pupil dilation, weakness

Notes on poisoning:

Horses that ingested black locust leaves, sprouts, and bark were poisoned and died. Symptoms are similar to those of cattle and include anorexia, weakness, posterior paralysis, nausea, coldness of the extremities, and pupil dilation. Symptoms of colic also occur. In severe cases, death occurs. Postmortem findings showed mucous inflammation of the gastrointestinal tract and occasional severe gastroenterititis. In some cases a yellowish pigmentation of the membranes occurred (Hansen 1924, Kingsbury 1964).

Humans

General symptoms of poisoning:

Death, nausea, pupil dilation, vomiting

Notes on poisoning:

Humans, usually children, were poisoned after ingesting the bark of black locust. Symptoms include pupil dilation, feeble pulse, severe vomiting, and a death-like palor. The extremities may become cold. Intestinal inflammation, hemorrhaging of the lymphatic tissues, and possible liver damage often occur. Fatalities are rare. The chances of poisoning are rare. Children should not be allowed to ingest plant material from this tree (Hansen 1924, Kingsbury 1964).

Poultry

General symptoms of poisoning:

Liver, congestion of

Notes on poisoning:

Chickens were poisoned after ingesting leaf material. Degenerative changes in the liver and kidney occurred. A toxic phytohemagglutinin extracted from the plant caused fatty degeneration of the liver and death in chick embryos, at doses of 0.25-2.0 mg per egg (Kingsbury 1964, Cooper and Johnson 1984).

Sheep

General symptoms of poisoning:

Anorexia

Notes on poisoning:

Ingesting the seed pods has caused minor illness in sheep (Kingsbury 1964).