Skip to main content
ARS Home » Research » Publications at this Location » Publication #160292


item Helling, Charles

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/20/2004
Publication Date: 6/24/2004
Citation: Helling, C.S. 2004. Narcotic plant control by herbicides: Environmental issues [abstract]. 4th International Weed Science Congress. S22MT05P04. p. 69.

Interpretive Summary:

Technical Abstract: The world-wide problem of narcotic drugs stems largely from the illicit cultivation of Cannabis sativa (marijuana), Erythroxylum spp. (coca), and Papaver somniferum (opium poppy). The solution can be approached as a specialized weed control problem, albeit where the target is a crop. Drug crops often are grown in dangerous, inaccessible locations, and in large-scale. Their control, in such cases, is best done by using herbicides. Environmental stewardship and government policy mandate understanding the impacts of herbicides used, or considered, for narcotic plant control. The overarching objective of a long series of USDA experiments was to determine how such herbicides behave in (especially) tropical sites associated with coca and poppy cultivation in Latin America. This was done by (a) determining herbicide persistence and leaching in test plots or coca fields in Peru, Panama, and the U.S.; (b) isolating soil bacteria capable of utilizing test herbicides; (c) conducting algal toxicity studies; and (d) observing environmental impacts from large-scale application of glyphosate on Colombian coca. The behavior of two potential coca control herbicides was notably consistent over three tropical locations, with distinctly shorter half-lives than typically reported for temperate areas. Due to unique risks (hostile ground-fire, physical hazards) associated with aerial application, especially for coca and poppy eradication, herbicides are applied at higher altitude and speed than done for conventional weed or brush control. Despite this, off-target collateral damage has been remarkably low, and environmental risks seem minimal.