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July 15, 2009
Integrated strategies, such as
controlling seed sets, may reduce the frequency of glyphosate
resistance in ryegrass, according to a new report in the most
recent issue of Weed Science.
Glyphosate is the most widely used herbicide in the world and is
often applied to plants that readily develop resistance to other
treatments. However, certain ryegrass species, once effectively
controlled by glyphosate, have evolved to resist even its
application. This report focuses on a review of the evolution of
glyphosate resistance in ryegrass, the mechanisms of this
resistance, and suggestions for the management of ryegrass.
The over-reliance on glyphosate to control certain ryegrass
species, even to the exclusion of other practices, has enabled
the plant to develop a resistance to the herbicide. Two
resistance mechanisms have been determined: reduction of the
translocation of glyphosate to the shoot meristem and roots, and
modifications in the target site on the EPSPS gene. It also
appears as though a cross between individuals carrying each of
these mechanisms results in a multiple resistance to glyphosate.
Research into management of ryegrass has shown that
glyphosate-resistant plants do suffer a fitness cost, however,
which can be exploited by using integrated strategies such as
herbicide rotation and crop competition to control the plant.
To read the entire article, “A Decade of Glyphosate-Resistant
Lolium around the World: Mechanisms, Genes, Fitness, and
Agronomic Management” (Vol. 57(4):435-441, 2009), visit
http://www.allenpress.com/pdf/wees/WEES_57.4_435_441.pdf
Weed Science is published by the
Weed Science Society of America,
a nonprofit professional society that was founded in 1956 to
encourage and promote the development of knowledge concerning
weeds and their impact on the environment. The Weed Science
Society of America promotes research, education, and extension
outreach activities related to weeds, provides science-based
information to the public and policy makers, and fosters
awareness of weeds and their impacts on managed and natural
ecosystems. |
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