Purposefully Introduced Plants that Have Become Noxious or Poisonous Weeds

Abstract

Purposefully introduced plants that have become weeds cost the United States millions of dollars annually by reducing yields of crops and livestock, clogging navigable and recreational waterways, reducing productivity and value of grazing lands, poisoning humans and livestock, and increasing weed control costs. Research is in progress to develop methods of intercepting foreign plants that might be toxic to livestock if introduced on western ranges and pastures. Methods of intercepting include identifying poisonous plants from seed inventories, chemical analysis, chemotaxonomic investigations of biochemical relationships between related taxa, and feeding suspected plants to laboratory and domestic animals.