Colombia to Spray Coca Cops with Stronger Herbicide

Back to Map Page June, 1998 Environmental Consequences Could Be Severe After more than a decade of pressure, the Colombian government agreed in June to US demands to test a new herbicide for use in the war on cocaine producers. The new herbicide is tebuthiuron, a pelletized herbicide that is more effective, persistent, and environmentally dangerous than herbicides used in Colombia in the past. Critics, including a US General Accounting Office report of February 1998, argue that this new offensive is taking place at the expense of other, possibly more effective, interdiction efforts. For four years Colombian police have used airplanes to spray fields with liquid herbicides. But several problems have made these treatments relatively ineffective. Applications by air frequently miss target plants, or reach only parts of targeted fields, so that only about 30% of treated plants are killed. Rainfall quickly disperses and dilutes liquid herbicides, further reducing effectiveness. Most important, applications must be done low to the ground, at times of day when there is no rain and little wind to cause drift from the target fields. These low-level applications in fine weather make airplanes especially vulnerable to attack from the ground.   Colombia's south-central provinces are likely to recieve the greatest focus in the tebuthiuron application program. In contrast, tebuthiuron comes in pea-sized solid pellets, which can be dropped from higher altitudes even in rainy or windy weather. This makes tebuthiuron applications much safer for pilots. The solid pellets are expected to hit target fields with better accuracy, increasing the effectiveness of applications. Pellets break down and disperse more slowly than liquid herbicides, making the application more likely to kill plants. At the same time, tebuthiuron, which is sold in the United States under the brand name Spike, is a highly toxic, extremely persistent, broad-spectrum herbicide. Labels warn that even slight exposure to roots can kill trees. Persistence means that the chemical compound breaks down slowly, so that the herbicide can remain potent for 15 months. In a moist environment, such as in the rain forests of southern Colombia, water can quickly carry persistent herbicides through the environment. Broad-spectrum herbicides are lethal to a wide variety of vegetation. Tebuthiuron is effective not just against coca plants but also against any broadleaf or woody vegetation--including mature trees, shrubs, and vines. Environmentalists and members of the Colombian government worry that the persistence of the herbicide will make fields useless for subsistence agriculture after the coca plants have been killed. The region's peasants rely on subsistence farming in the forest for survival. Damage to forests surrounding coca fields could be extreme. And further deforestation is inevitable as coca growers--and subsistence farmers--are forced to clear more land for farming after tebuthiuron applications. Fears of Herbicide Persistence, Water Contamination One of the most urgent worries, though, is water contamination. The persistent herbicide moves and disperses quickly once it enters streams or groundwater. Although the herbicide is designed to kill plants, it is also poisonous to animals, and dispersal by water poses serious health threats to local farmers and to wildlife. The maker of tebuthiuron, a subsidiary of Dow Chemical Company, insists that the chemical be used only under carefully controlled conditions and where there are no nearby water bodies, streams, or shallow groundwater. But uncontrolled conditions and heavy rainfall are precisely the reasons the US government has insisted on tebuthiuron's use on Colombia's cocaine fields. The company strongly opposes this use of the herbicide. If approved for use, tebuthiuron could be used on more than 80,000 hectares (nearly 200,000 acres), mainly in the southern provinces of Caqueta, Putumayo, Guaviare, and Meta. Some Illegal Use Already Underway? Reports have surfaced that covert tebuthiuron applications have been under way at least since last spring, long before the Colombian government agreed to its testing. Until July the chemical was strictly banned in the country, but early last spring farmers were reporting on finding pea-sized pellets in their fields--pellets that experts contend could only be tebuthiuron. Pellets were found in nearby subsistence food plots, as well as in illegal coca fields. To read more, see Environmental Science, A Global Concern, Cunningham and Saigo, 5th ed. Persistence and mobility of pesticides and herbicides: page 256 Tropical deforestaton: page 297 Environmental Science, Enger and Smith, 6th ed. Herbicides: page 268 Back to Map Page feedback form | permissions | international | locate your campus rep | request a review copy digital solutions | publish with us | customer service | mhhe home Copyright ©2001 The McGraw-Hill Companies. Any use is subject to the Terms of Use and Privacy Policy. McGraw-Hill Higher Education is one of the many fine businesses of the The McGraw-Hill Companies.