Hilgardia
Hilgardia
Hilgardia
University of California
Hilgardia

Aerial application of clopyralid demonstrates little drift potential and low toxicity to toads

Authors

Joseph M. DiTomaso
Jessica R. Miller
Guy B. Kyser
Art W. Hazebrook
Joel Trumbo
David Valcore
Vanelle F. Carrithers

Authors Affiliations

J.M. DiTomaso is Non-Crop Extension Weed Ecologist, Department of Vegetable Crops, UC Davis; J.R. Miller is Graduate Student, Department of Vegetable Crops, UC Davis; G.B. Kyser is Staff Research Associate, Department of Vegetable Crops, UC Davis; A.W. Hazebrook is Land Rehabilitation and Maintenance Coordinator, Center for Environmental Management of Military Lands, Colorado State University, Fort Hunter Liggett; J. Trumbo is Environmental Scientist, California Department Fish and Game (DFG), Rancho Cordova; D. Valcore is Senior Research Scientists, Dow AgroSciences, Indianapolis; V.F. Carrithers is Senior Research Scientists, Dow AgroSciences, Indianapolis.

Publication Information

Hilgardia 58(3):154-158. DOI:10.3733/ca.v058n03p154. July 2004.

PDF of full article, Cite this article

Abstract

The herbicide clopyralid (Transline) is commonly applied by air to control yellow starthistle, a noxious weed, in California. In laboratory studies, clopyralid toxicity in Fowler's toad was low, indicating a wide safety margin when used under field conditions. In addition, monitoring of clopyralid drift following aerial application demonstrated that 98-foot (30-meter) buffers between treatment areas and water sources provided adequate drift protection for an adjacent stream and vernal pools. Nevertheless, to ensure that movement of the herbicide to water sources is minimized, it is important to prevent application error, particularly accidental encroachment into established buffer zones. This study demonstrated that drift potential for clopyralid was minimal even with an aerial application and a slight downwind breeze toward sensitive aquatic sites. It is also the first report demonstrating a high tolerance to clopyralid in larval toads.

References

Bird SL, Perry SG, Ray SL, Teske ME. Evaluation of the AgDISP aerial spray algorithm in the AgDRIFT model. J Environ Toxicol Chem. 2002. 21(3):672-81. https://doi.org/10.1897/1551-5028(2002)021/0672:EOTAAS/2.0.CO;2

[DFG] California Department of Fish and Game. Aquatic Toxicology Laboratory Report P-2173. 2000. September

DFG. Quality assurance manual for the aquatic toxicology laboratory. Standard operating procedure for Pimephales promelas 96-h definitive acute toxicity test. 2001. December

DiTomaso JM, Kyser GB, Orloff SB, et al. New growth regulator herbicide provides excellent control of yellow starthistle. Cal Ag. 1999. 53(2):12-6.

DiTomaso JM, Kyser GB, Orloff SB, Enloe SF. Integrated strategies offer site-specific control of yellow starthistle. Cal Ag. 2000. 54(6):30-6.

DiTomaso JM, Lanini WT, Thomsen CD, et al. Yellow starthistle. 1999. UC DANR Pest Notes Pub 7402. 4 p

Dow AgroSciences. Clopyralid: A North American Technical Profile. 1998. Indianapolis, IN. http://wric.ucdavis.edu/yst/manage/ClopTechProfile.pdf . 32 p.

Maddox DM. Introduction, phenology, and density of yellow starthistle in coastal, intercoastal, and central valley situations in California. 1981. USDA-ARS, ARR-W-20, p 1–33

Osborne M. Integrated Training Area Management (ITAM) program, Fort Hunter Liggett, Calif. 1998. Land Condition Trend Analysis (LCTA) Component. Annual Report, Center for Ecological Management of Military Lands, Col State Univ. Fort Collins, CO.

Pitcairn MJ, DiTomaso JM, Hoddle MS. Range-land and uncultivated areas: Integrating biological control agents and herbicides for starthistle control. California Conference on Biological Control II. 2000. p 65–72

Thomsen CD, Williams WA, Olkowski W, Pratt DW. Grazing, mowing and clover plantings control yellow starthistle. IPM Practitioner. 1996. 18:1-4.

[US EPA] US Environmental Protection Agency. Methods for measuring the acute toxicity of effluents and receiving water to freshwater and marine organisms. 4th ed. 1993. EPA/600/4-90/027F. Environmental Monitoring Systems Laboratory, Cincinnati, OH.

Zucker E. Hazard Evaluation Division, Standard Evaluation Procedure: Acute toxicity test for freshwater fish. 1985. EPA-540/9/85-006. U.S. Environmental Protection Agency, Office of Pesticide Programs, Washington, DC.

DiTomaso J, Miller J, Kyser G, Hazebrook A, Trumbo J, Valcore D, Carrithers V. 2004. Aerial application of clopyralid demonstrates little drift potential and low toxicity to toads. Hilgardia 58(3):154-158. DOI:10.3733/ca.v058n03p154
Webmaster Email: wsuckow@ucanr.edu