Hilgardia
Hilgardia
Hilgardia
University of California
Hilgardia

Glyphosate-resistant hairy fleabane documented in the Central Valley

Authors

Anil Shrestha
Bradley D. Hanson
Kurt J. Hembree

Authors Affiliations

A. Shrestha is Integrated Pest Management Weed Ecologist, UC Statewide IPM Program, UC Kearney Agricultural Center, Parlier; B.D. Hanson is Research Agronomist, U.S. Department of Agriculture/Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Parlier; K.J. Hembree is Farm Advisor, UC Cooperative Extension, Fresno County.

Publication Information

Hilgardia 62(3):116-119. DOI:10.3733/ca.v062n03p116. June 2008.

PDF of full article, Cite this article

Abstract

In recent years, growers and pest consultants have reported poor control of the weed hairy fleabane in some areas of the Central Valley. Hairy fleabane seeds were collected from Esparto, Fresno and Reedley, Calif., and greenhouse-grown seedlings were treated at several different glyphosate rates and compared with an untreated control. None of the Esparto or Fresno plants survived glyphosate rates greater than 0.78 pounds acid equivalent per acre (lb ae/ac), while some of the plants from Reedley survived even the highest rate of glyphosate tested (12.4 lb ae/ac). The dose required to reduce plant dry weights by 50% (GR50) of the Esparto plants ranged from 0.28 to 0.30 lb ae/ac, whereas the GR50 of the Fresno and Reedley plants ranged from 0.26 to 0.61 and 0.92 to 2.88 lb ae/ac, respectively. This study showed that the hairy fleabane plants from Reedley were much more tolerant of glyphosate than either of the other two biotypes and, based on the GR50, the level of resistance ranged from 3-to 10-fold greater.

References

Baylis AD. Why glyphosate is a global herbicide: Strengths, weaknesses and prospects. Pest Manag Sci. 2000. 56:299-308. https://doi.org/10.1002/(SICI)1526-4998(200004)56:4

Christoffers MJ. Genetic aspects of herbicide-resistant weed management. Weed Technol. 1999. 13:647-52.

Heap I. International survey of herbicide resistant weeds. 2008. www.weedscience.org

Holt JS. History of identification of herbicide-resistant weeds. Weed Technol. 1992. 6:615-20.

Noyes RD. Biogeographical and evolutionary insights on Erigeron and allies (Asteraceae) from ITS sequence data. Plant System Evolu. 2000. 220:93-114. doi:10.1007/BF00985373 https://doi.org/doi:10.1007/BF00985373

Shrestha A, van Hembree KJ. Growth stage influences level of resistance in glyphosate-resistant horseweed. Cal Ag. 2007. 61(2):67-70.

Simarmata M, Bughrara S, Penner D. Inheritance of glyphosate resistance in rigid ryegrass (Lolium rigidum) from California. Weed Sci. 2005. 53:615-9. doi:10.1614/WS-04-187R.1 https://doi.org/doi:10.1614/WS-04-187R.1

Urbano JM, Borrego A, Torres V, et al. Glyphosate-resistant hairy fleabane (Conyza bonariensis) in Spain. Weed Technol. 2007. 21:396-401. doi:10.1614/WT-06-096.1 https://doi.org/doi:10.1614/WT-06-096.1

Woodburn A. Glyphosate production, pricing and use worldwide. Pest Manag Sci. 2000. 56:309-12. https://doi.org/10.1002/(SICI)1526-4998(200004)56:4

Shrestha A, Hanson B, Hembree K. 2008. Glyphosate-resistant hairy fleabane documented in the Central Valley. Hilgardia 62(3):116-119. DOI:10.3733/ca.v062n03p116
Webmaster Email: wsuckow@ucanr.edu