Picloram
Encyclopedia
Picloram is a systemic herbicide used for general woody plant control, sold under the trade names Tordon and Grazon. It also controls a wide range of broad-leaved weeds, but most grasses are resistant. A chlorinated
derivative of picolinic acid
, picloram is in the pyridine
family of herbicides.
Picloram can be sprayed on foliage, injected into plants, applied to cut surfaces, or placed at the base of the plant where it will leach to the roots. Once absorbed by the foliage, stem, or roots, picloram is transported throughout the plant.
During the Vietnam War, a mixture of picloram and 2,4-D, known as Agent White
, was sprayed on plants that survived treatment with Agent Orange
(2,4,5-T and 2,4-D).
Picloram is of moderate toxicity to the eyes and only mildly toxic on the skin. There is no documented history of human intoxication by picloram so symptoms of acute exposure are difficult to characterize. A possible symptom from massive amounts would be nausea.
Picloram is the most persistent of its family of herbicides. It does not adhere to soil and so may leach to groundwater, and has in fact been detected there. It is degraded in soil and water mainly by microbes. Picloram has very little tendency to accumulate in aquatic life.
Gardeners who use dung as fertilizer should check to make certain that the animal source has not grazed on picloram treated hay, as the dung still has broadleaf killing potency.
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...
derivative of picolinic acid
Picolinic acid
Picolinic acid is a pyridine compound with a carboxyl side chain at the 2-position. It is an isomer of nicotinic acid, which has the carboxyl side chain at the 3-position. It is a catabolite of the amino acid tryptophan.- Chelating properties :...
, picloram is in the pyridine
Pyridine
Pyridine is a basic heterocyclic organic compound with the chemical formula C5H5N. It is structurally related to benzene, with one C-H group replaced by a nitrogen atom...
family of herbicides.
Picloram can be sprayed on foliage, injected into plants, applied to cut surfaces, or placed at the base of the plant where it will leach to the roots. Once absorbed by the foliage, stem, or roots, picloram is transported throughout the plant.
During the Vietnam War, a mixture of picloram and 2,4-D, known as Agent White
Agent White
Agent White is the code name for a powerful herbicide and defoliant used by the U.S. military in its Herbicidal warfare program during the Vietnam War. The name comes from the white stripe painted on the barrels to identify the contents...
, was sprayed on plants that survived treatment with Agent Orange
Agent Orange
Agent Orange is the code name for one of the herbicides and defoliants used by the U.S. military as part of its herbicidal warfare program, Operation Ranch Hand, during the Vietnam War from 1961 to 1971. Vietnam estimates 400,000 people were killed or maimed, and 500,000 children born with birth...
(2,4,5-T and 2,4-D).
Picloram is of moderate toxicity to the eyes and only mildly toxic on the skin. There is no documented history of human intoxication by picloram so symptoms of acute exposure are difficult to characterize. A possible symptom from massive amounts would be nausea.
Picloram is the most persistent of its family of herbicides. It does not adhere to soil and so may leach to groundwater, and has in fact been detected there. It is degraded in soil and water mainly by microbes. Picloram has very little tendency to accumulate in aquatic life.
Gardeners who use dung as fertilizer should check to make certain that the animal source has not grazed on picloram treated hay, as the dung still has broadleaf killing potency.
External links
- Tordon webpage, Dow AgroSciencesDow AgroSciencesDow AgroSciences LLC is a wholly owned subsidiary of the Dow Chemical Company specializing in not only agricultural chemicals such as pesticides, but also seeds and biotechnology solutions. The company is based in Indianapolis, Indiana, in the United States...