International Survey of Herbicide-Resistant Weeds

Countries Weeds Herbicides Mutations Graphs References Researchers
(Gamochaeta pensylvanica)

PSI Electron Diverter (D/22)

Australia, Queensland
Pennsylvania Everlasting (Gamochaeta pensylvanica) is a dicot weed in the Asteraceae family.  In Queensland this weed first evolved resistance to Group D/22 herbicides in 2015 and infests Sugarcane for sugar, and Vegetables.   Group D/22 herbicides are known as PSI Electron Diverter (Photosystem-I-electron diversion).  Research has shown that these particular biotypes are resistant to paraquat and they may be cross-resistant to other Group D/22 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.

If we do not have a picture for this weed, or you can provide a better picture (scan, digital camera etc) please please e-mail it to us.

QUIK STATS (last updated Feb 08, 2016 )

Common NamePennsylvania Everlasting
SpeciesGamochaeta pensylvanica
GroupPSI Electron Diverter (D/22)
LocationAustralia, Queensland
Situation(s)Sugarcane for sugar, and Vegetables
Contributors - (Alphabetically)Christopher Preston 
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Confirmation Tests

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

Genetic studies on Group D/22 resistant Pennsylvania Everlasting 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 D/22 resistant Pennsylvania Everlasting from Queensland please update the database.
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University Of Adelaide - Waite Campus
Crc For Australian Weed Management And School Of Agriculture
Box 2146
Adelaide, 5064, South Australia
Email Christopher Preston


The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Queensland have been instrumental in providing you this information. Particular thanks is given to Christopher Preston for providing detailed information.
Herbicide Resistant Pennsylvania Everlasting Globally
(Gamochaeta pensylvanica)
Herbicide Resistant Pennsylvania Everlasting Globally
(Gamochaeta pensylvanica)
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Herbicide Resistant Pennsylvania Everlasting Globally
(Gamochaeta pensylvanica)
#CountryFirstYearSituationActive IngredientsSite of Action
1 Australia (Queensland) AustraliaQueensland2015 Sugarcane for sugar, and Vegetables paraquat 1 PSI Electron Diverter (D/22)
298Gamochaeta pensylvanicaPennsylvania Everlasting11029
2 JapanJapan 1991 Mulberry paraquat 25 PSI Electron Diverter (D/22)
298Gamochaeta pensylvanicaPennsylvania Everlasting7789
Literature about Similar Cases

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