Skip to main content

Documentation of landoltia (Landoltia punctata) resistance to diquat

  • Tyler J. Koschnick, William T. Haller (a1) and Les Glasgow (a2)

Landoltia was collected and cultured from a canal in Lake County, Florida, where diquat was used repeatedly during the past 20–30 yr for duckweed control. Recent applications of diquat failed to provide adequate control of duckweed, and a new commercial formulation of diquat was suspected. The new formulation was not the cause of reduced efficacy. Static exposures (48 h) to various concentrations of diquat were used to compare the susceptibility of the Lake County landoltia accession to one never exposed to diquat. These static tests indicated that landoltia, from a population with no prior history of herbicide treatment, was extremely susceptible to diquat. The accession from Lake County, FL had developed resistance to diquat, and was also cross resistant to paraquat. The resistance factor was 50 for diquat and 29 for paraquat. The Lake County accession also exhibited reduced ion leakage after diquat exposure under light and dark conditions. This suggests the resistance mechanism to the bipyridylium herbicides in landoltia is independent of photosynthetic electron transport. This research documents the first aquatic plant species that has developed resistance to the bipyridylium herbicides.

Corresponding author
Corresponding author. Department of Agronomy, Center for Aquatic and Invasive Plants, Institute of Food and Agricultural Sciences, University of Florida, 7922 NW 71st St., Gainesville, FL 32653;
Hide All
Arnon, D. I. 1949. Copper enzymes in isolated chloroplasts. Polyphenoloxidase in Beta vulgaris . Plant Physiol 24:115.
Blackburn, R. D. and Weldon, L. W. 1965. The sensitivity of duckweeds (Lemnaceae) and azolla to diquat and paraquat. Weeds 13:147149.
Calderbank, A. and Slade, P. 1976. Diquat and paraquat. Pages 501540 in Kearney, P. C. and Kaufman, D. D. eds. Herbicides Chemistry, Degradation, and Mode of Action. 2nd ed. New York: Marcel Dekker.
Connard, A. J. and Criddle, W. J. 1975. A rapid method for the simultaneous determination of paraquat and diquat on pond and river waters by pyrolysis and gas chromatography. The Analysts 100:848853.
Heap, I. 2004. The International Survey of Herbicide Resistant Weeds.
Hiscox, J. D. and Israelstam, G. F. 1979. A method for the extraction of chlorophyll from leaf tissue without maceration. Can. J. Bot 57:13321334.
Langeland, K. A., Hill, O. N., Koschnick, T. J., and Haller, W. T. 2002. Evaluation of a new formulation of Reward landscape and aquatic herbicide for control of duckweed, waterhyacinth, waterlettuce, and hydrilla. J. Aquat. Plant Manage 40:5153.
MacDonald, G. E., Shilling, D. G., and Bewick, T. A. 1993. Effects of endothall and other aquatic herbicides on chlorophyll fluorescence, respiration, and cellular integrity. J. Aquat. Plant Manage 31:5055.
O'Brien, M. C. and Prendeville, G. N. 1978. A rapid bioassay for determination of paraquat and diquat in water. Weed Res 18:301303.
Peterson, H. G., Boutin, C., and Freemark, K. E. 1997. Toxicity of hexazinone and diquat to green algae, diatoms, cyanobacteria and duckweed. Aquat. Toxicol 39:111134.
Saeger, A. 1934. Spirodela oligorrhiza collected in Missouri. Bull. Torrey Bot. Club 61:233236.
[SAS] Statistical Analysis Systems. 1999. SAS. Version 8.1. Cary, NC: Statistical Analysis Systems Institute.
Suleiman, S. A. and Stevens, J. B. 1987. Bipyridylium herbicide toxicity: effects of paraquat and diquat on isolated rat hepatocytes. J. Environ. Pathol. Toxicol. Oncol 7:7384.
Wang, W. 1990. Literature review on duckweed toxicity testing. Environ. Res 52:722.
Wong, R. C. and Stevens, J. B. 1986. Bipyridylium herbicide toxicity in vitro: comparative study of the cytotoxicity of paraquat and diquat toward the pulmonary alveolar macrophage. J. Toxicol. Environ. Health 18:393407.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Weed Science
  • ISSN: 0043-1745
  • EISSN: 1550-2759
  • URL: /core/journals/weed-science
Please enter your name
Please enter a valid email address
Who would you like to send this to? *



Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed