Tares, also known as vetches, are plants primarily within the Vicia genus. They are common in gardens, fields, and along roadsides. This article explores their potential toxicity to humans and animals and the implications of their consumption.
What Are Tares?
The plants known as “tares” primarily belong to the Vicia genus, encompassing over 240 species in the legume family. Common vetch (Vicia sativa) and hairy vetch (Vicia villosa) are prominent examples. These plants typically exhibit a vine-like growth habit, often climbing or sprawling, with fine compound leaves.
Their flowers are generally purple, though colors vary, and they produce small pods containing seeds. Vetches are found naturally across Europe, Africa, the Americas, and Asia, common in agricultural fields, disturbed areas, and as cover crops. While “tares” can also refer to darnel (Lolium temulentum), a poisonous grass, this article focuses on Vicia species due to their agricultural presence and documented toxicity.
How Tares Can Be Toxic
Certain species of tares contain compounds harmful if ingested. These include cyanogenic glycosides, which release hydrogen cyanide upon digestion, and other anti-nutritional factors like canavanine, beta-cyano-L-alanine, and saponins. The seeds are considered the most toxic part, though young shoots also pose a risk.
Toxicity is more likely when large quantities are consumed, especially raw. Common vetch seeds, for example, contain cyanide compounds active upon exposure to stomach acid. While some vetch species are cultivated for forage, specific toxicity varies significantly between species and within different plant parts.
Recognizing Poisoning Symptoms and Taking Action
Symptoms of tare poisoning vary by species, quantity ingested, and individual sensitivity. In humans, consumption can lead to gastrointestinal issues like nausea, vomiting, diarrhea, and abdominal pain. Other signs include headache, weakness, confusion, difficulty breathing, and in severe cases, convulsions or loss of consciousness.
Animals, particularly livestock, can exhibit loss of appetite, lethargy, and neurological signs such as staggering or abnormal behavior. Skin lesions, hair loss, dermatitis, and swelling are also reported. In severe instances, organ damage, weight loss, and death can occur.
If poisoning is suspected in humans, immediately contact a poison control center. For animals, contact a veterinarian promptly. Do not attempt to induce vomiting unless advised by a medical professional.
Safe Handling and Prevention
Preventing exposure to toxic levels of tares involves careful management, especially in areas accessible to children, pets, and livestock. In gardens, remove vetch plants, particularly before they set seed, and dispose of them properly. This prevents accidental ingestion.
For livestock, managing grazing areas with vetches is important. While some vetch species are used as forage, consuming large quantities, especially mature plants with abundant seeds, can be problematic. Providing alternative feed sources and monitoring animals for illness reduces risks. Always ensure proper identification of plants before allowing consumption to avoid harm.