International Survey of Herbicide-Resistant Weeds

Countries Weeds Herbicides Mutations Graphs References Researchers
GROUP G/9 RESISTANT HAIRY FLEABANE
(Conyza bonariensis)


EPSP synthase inhibitors (G/9)

South Africa, Western Cape
INTRODUCTION HAIRY FLEABANE
Hairy Fleabane (Conyza bonariensis) is a dicot weed in the Asteraceae family.  In South Africa this weed first evolved resistance to Group G/9 herbicides in 2003 and infests Grapes, and Orchards.   Group G/9 herbicides are known as EPSP synthase inhibitors (Inhibition of EPSP synthase).  Research has shown that these particular biotypes are resistant to glyphosate and they may be cross-resistant to other Group G/9 herbicides.

The 'Group' letters/numbers that you see throughout this web site refer to the classification of herbicides by their site of action. To see a full list of herbicides and HRAC herbicide classifications click here.

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QUIK STATS (last updated Aug 04, 2003 )

Common NameHairy Fleabane
SpeciesConyza bonariensis
GroupEPSP synthase inhibitors (G/9)
Herbicidesglyphosate
LocationSouth Africa, Western Cape
Year2003
Situation(s)Grapes, and Orchards
Contributors - (Alphabetically)Andrew Cairns 
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NOTES ABOUT THIS BIOTYPE

GENERAL

Andrew Cairns
Conyza bonariensis in the Western Cape.

In January 2003 reports were received from the Breede Valley (about 100km north east of Cape Town) of glyphosate failing to control Conyza bonariensis at registered dosage rates. Seed from plants growing in a deciduous fruit orchard in the area were collected and germinated in pots. The seedlings were subsequently transplanted into pots and a month later the plants were subjected to a dose response trial with glyphosate. A control population of the C. bonariensis derived from seed collected from a population of the weed growing at Stellenbosh University’s experimental farm, Welgevallen, was similarly treated. At the time of spraying, the plants had 10-12 leaves and were still in the rosette stage. The weeds were subjected to a range of glyphosate dosage rates viz. 0.36, 0.72, 1.08, 1.44, 2.16, 2.88, and 3.60 kg a.e. glyphosate ha-1. Four replicates per treatment were used.

From the results of this dose response trial (Table 1), it is clear that the Breede Valley population was not controlled at all at the registered dosage rate (1.08kg a.e. glyphosate ha-1) and only 17% of the weeds were controlled at twice the registered dose of glyphosate. The control (Welgevallen) population was fully controlled at all dosage rates above 0.36 kg a.e glyphosate ha-1. The trial was rated 56 days after treatment.

Table 1. Dose response of two Western Cape populations of Conyza bonariensis to glyphosate.

 

Control (%)

Treatment

Population

(kg a.e. glyphosate ha-1) Breede ValleyWelgevallen
000
0.36050
0.720100
1.080100
1.440100
2.1617100
2.8883100
3.6094100

Subsequent screening has identified 3 more glyphosate-resistant populations of C. bonariensis (all from the Breede Valley). Work is in progress to map the extent of glyphosate resistant populations of C. bonariensis in the Western Cape and to identify cost effective control strategies.

A.L.P. Cairns
Department of Agronomy
University of Stellenbosch

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ACADEMIC ASPECTS

Confirmation Tests

Field, and Greenhouse trials comparing a known susceptible Hairy Fleabane biotype with this Hairy Fleabane biotype have been used to confirm resistance. For further information on the tests conducted please contact the local weed scientists that provided this information.
 
Genetics

Genetic studies on Group G/9 resistant Hairy Fleabane have not been reported to the site.  There may be a note below or an article discussing the genetics of this biotype in the Fact Sheets and Other Literature
 
Mechanism of Resistance

The mechanism of resistance for this biotype is either unknown or has not been entered in the database.  If you know anything about the mechanism of resistance for this biotype then please update the database.
 
Relative Fitness

There is no record of differences in fitness or competitiveness of these resistant biotypes when compared to that of normal susceptible biotypes.  If you have any information pertaining to the fitness of Group G/9 resistant Hairy Fleabane from South Africa please update the database.
 
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CONTRIBUTING WEED SCIENTISTS

ANDREW CAIRNS
University Of Stellenbosch
Department Of Agronomy
Land Resources& Environmental Sci Dept
334 Leon Johnson Hall,
Matieland, 7602
South Africa
Email Andrew Cairns

ACKNOWLEDGEMENTS

The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in South Africa have been instrumental in providing you this information. Particular thanks is given to Andrew Cairns for providing detailed information.
Herbicide Resistant Hairy Fleabane Globally
(Conyza bonariensis)
Herbicide Resistant Hairy Fleabane Globally
(Conyza bonariensis)
Drag a column header and drop it here to group by that column
Herbicide Resistant Hairy Fleabane Globally
(Conyza bonariensis)
#CountryFirstYearSituationActive IngredientsSite of Action
1 ArgentinaArgentina 2012 Soybean glyphosate 48 EPSP synthase inhibitors (G/9)
60Conyza bonariensisHairy Fleabane17100
2 Australia (New South Wales ) AustraliaNew South Wales 2010 Industrial sites, and Roadsides glyphosate 1 EPSP synthase inhibitors (G/9)
60Conyza bonariensisHairy Fleabane5512
3 Australia (Queensland) AustraliaQueensland2011 Roadsides glyphosate 1 EPSP synthase inhibitors (G/9)
60Conyza bonariensisHairy Fleabane5604
4 Australia (South Australia) AustraliaSouth Australia2011 Roadsides glyphosate 1 EPSP synthase inhibitors (G/9)
60Conyza bonariensisHairy Fleabane5605
5 Australia (New South Wales ) AustraliaNew South Wales 2016 Grapes paraquat 1 PSI Electron Diverter (D/22)
60Conyza bonariensisHairy Fleabane13045
6 BrazilBrazil 2005 Corn (maize), Fruit, Soybean, and Wheat glyphosate 5 EPSP synthase inhibitors (G/9)
60Conyza bonariensisHairy Fleabane5264
7 ColombiaColombia 2006 Coffee glyphosate 10 EPSP synthase inhibitors (G/9)
60Conyza bonariensisHairy Fleabane5295
8 EgyptEgypt 1989 Unspecified paraquat 15 PSI Electron Diverter (D/22)
60Conyza bonariensisHairy Fleabane383
9 GreeceGreece 2010 Grapes, Olive, and Orchards glyphosate 19 EPSP synthase inhibitors (G/9)
60Conyza bonariensisHairy Fleabane5590
10 IsraelIsrael 1993 Forests, and Industrial sites atrazine, and simazine 23 Photosystem II inhibitors (C1/5)
60Conyza bonariensisHairy Fleabane102
11 IsraelIsrael 1993 Forests, and Industrial sites chlorsulfuron 23 ALS inhibitors (B/2)
60Conyza bonariensisHairy Fleabane103
12 IsraelIsrael 2005 Roadsides glyphosate 23 EPSP synthase inhibitors (G/9)
60Conyza bonariensisHairy Fleabane5464
13 JapanJapan 1989 Roadsides diquat, and paraquat 25 PSI Electron Diverter (D/22)
60Conyza bonariensisHairy Fleabane128
14 PortugalPortugal 2010 Orchards glyphosate 34 EPSP synthase inhibitors (G/9)
60Conyza bonariensisHairy Fleabane5539
15 South AfricaSouth Africa 2003 Grapes, and Orchards paraquat 37 PSI Electron Diverter (D/22)
60Conyza bonariensisHairy Fleabane5191
16 South AfricaSouth Africa 2003 Grapes, and Orchards glyphosate 37 EPSP synthase inhibitors (G/9)
60Conyza bonariensisHairy Fleabane5192
17 SpainSpain 1987 Orchards simazine 38 Photosystem II inhibitors (C1/5)
60Conyza bonariensisHairy Fleabane181
18 SpainSpain 2004 Orchards glyphosate 38 EPSP synthase inhibitors (G/9)
60Conyza bonariensisHairy Fleabane5223
19 United States (California) United StatesCalifornia2007 Roadsides glyphosate 45 EPSP synthase inhibitors (G/9)
60Conyza bonariensisHairy Fleabane5310
20 United States (California) United StatesCalifornia2009 Corn (maize), Grapes, Orchards, and Roadsides glyphosate, and paraquat 45 Multiple Resistance: 2 Sites of Action
PSI Electron Diverter (D/22)
EPSP synthase inhibitors (G/9)
60Conyza bonariensisHairy Fleabane5390
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