| OCR Text |
Show Take-over of U.S. exposed They came to the United States in a variety of guises, and began to take over large areas, wiping out competitors, poisoning and killing. Sounds like a Mafia story, and the opposition is an arm of the governmentnot govern-mentnot the FBI in this case, but the USD A and collaborators. The invaders are plants, admitted to the USA because they seemed to fill a need. There were ornamentals, like water-hyacinths water-hyacinths that now clog canals and waterways in the South; like Macartney rose, that now infests one-half million acres of Texas grasslands; or musk thistle, that now infests one out of every 10 counties in the USA. There was Johnson grass, introduced for pastures, but which spread like wildfire and invaded cultivated culti-vated crops. Other introduced intro-duced forage species, such as kleingrass and sicklepod milkvetch, may be poisonous to livestock. "Some were like cancer; can-cer; they just didn't show up for years," said Co-burn Co-burn Williams, plant physiologist at the USDA's Poisonous Plant Research Laboratory at Utah State University, n co who is concerned with identifying the poisonous species. Williams has seen a marked rise in interest in toxic plants as a result of increased mining and revegetation activities in the West. Public agencies are seeking plants to rehabilitate public lands and which can adapt to spoils or mine dumps. The agencies want to be sure the plants that provide forage, ground cover and soil retention won't wind up killing animals. "We want to catch the undesirable plants before they come into the country and before they are introduced to various areas," Williams said. "We've intercepted a minimum of 50 plants that would be toxic to livestock." live-stock." Examples of poisonous introduced species include galenia, a succulent being considered for roadside plantings and firebreaks. If galenia is fertilized with nitrate fertilizers, the nitrate level in the plant can climb to more than four times the level considered toxic to livestock. live-stock. Many species of milk-vetch milk-vetch contain nitro compounds com-pounds that, are highly toxic to cattle and sheep. Seeds of the various plants are sent to Williams at USU and the USDA's Poisonous Plant Research Laboratory, and the plants are grown in the greenhouse, then tested test-ed in the labs. The results are sent out by Williams to plant introduction people Soil Conservation Service, county agents, university researchers and anyone in weeds and range work. How important is it all? Purely from the standpoint stand-point of range management manage-ment it is highly important. impor-tant. Williams pointed out three ways of measuring the economic wallop. "In the West, at least five percent of all grazing animals fall victim to poisonous plants each year," he stated. "Most of the losses are from native species, but some are from halogeton (an accidently introduced toxic tox-ic species). Add together the cost of livestock losses, the value of the land unusable because of poisonous plants, and the cost of control and there is a major economic impact." few CV --Hmr |
