Herbicide Resistant Weeds

GROUP C1/5 RESISTANT BRISTLY FOXTAIL (Setaria verticillata)
Spain

Saturday, July 31, 2010

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Bristly Foxtail

1.	Introduction
2.	Level of Infestation
3.	Quick Statistics
4.	Notes about this biotype
5.	Academic Aspects
6.	R Bristly Foxtail Globally
7.	Fact Sheets and Literature
8.	Contributing Weed Scientists
9.	Acknowledgements
10.	Where to now?

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Introduction

Level of Infestation

Bristly Foxtail (Setaria verticillata) is a monocot weed in the Poaceae family. In Spain this weed first evolved resistance to Group C1/5 herbicides in 1992 and infests corn. Group C1/5 herbicides are known as Photosystem II inhibitors (Inhibition of photosynthesis at photosystem II). Research has shown that these particular biotypes are resistant to atrazine and they may be cross-resistant to other Group C1/5 herbicides.

There is no information recorded in the database on the distribution or level of infestation of Group C1/5 resistant Bristly Foxtail from Spain. If you have some information on this please add it to the database.

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

QUIK STATS ( last updated Nov 20, 2000 )
Common Name	Bristly Foxtail
Species	Setaria verticillata
Group	Photosystem II inhibitors (C1/5)
Herbicides	atrazine
Location	Spain
Year	1992
Situation(s)	corn
Sites	unknown
Acres Infested	unknown
Contributors	Rafael De Prado
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NOTES ABOUT THIS BIOTYPE

GENERAL

Rafael De Prado

Prado-R-de; Romero-E; Menendez-J; Tena-M; De-Prado-R. 1992. Mechanism of resistance to atrazine in Setaria verticillata and Setaria faberi. In IXe Colloque international sur la biologie des mauvaises herbes, 16-18 September 1992, Dijon, France. 1992, 457-463

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MECHANISM

Rafael De Prado

Growth chamber experiments revealed that atrazine-resistant S.verticillata plants developed from seed collected from both atrazine-treated and non-treated maize fields in the province of Cordoba, whereas atrazine-resistant S. faberi biotypes only developed in the treated fields. The resistance to atrazine of S. verticillata from both situations was apparently due to detoxification by conjugation of the herbicide with glutathione. The atrazine-resistant S. faberi biotype could be explained by a dual mechanism: (i) a lower affinity of the herbicide for the target site in the D1 protein, and (ii) by conjugation. Although the non-treated biotype of S. faberi conjugated glutathione to atrazine, it did so less efficiently than the corresponding resistant biotype.

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ACADEMIC ASPECTS

Confirmation Tests

Greenhouse trials comparing a known susceptible Bristly Foxtail biotype with this Bristly Foxtail 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

The genetic basis of resistance for this biotype is either unknown or has not been entered in the database. If you know anything about the genetic inheritance of this biotype please update the database.

Mechanism of Resistance

Studies on the mechanism of resistance of Group C1/5 resistant Bristly Foxtail from Spain indicate that resistance is due to conjugation. There may be a note below or an article discussing the mechanism of resistance in the "Fact Sheets and Other Literature"

Relative Fitness

Triazine resistant weeds often exhibit a lower relative fitness when compared to susceptible biotypes. The most common mutation conferring triazine resistance (Ser 264 to Gly mutation of the psbA gene) also causes a reduction in CO₂ fixation, quantum yield, and seed and biomass production. There is no record in this database referring specifically to fitness studies on Group C1/5 resistant Bristly Foxtail from Spain.

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HERBICIDE RESISTANT BRISTLY FOXTAIL GLOBALLY
#	Country	Year	Sites	Acres	Mode of Action
1.	Spain	1992	unknown	unknown	Photosystem II inhibitors (C1/5)

FACT SHEETS AND OTHER LITERATURE	Format
At Present there are no articles on this case of resistance. Please help by adding an article.
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Scientific Abstracts on Herbicide Resistant Setaria verticillata
In vitro studies on detection of trifluralin resistance in Setaria verticillata (L.) P.B.: In vitro testlerle trifluraline karsi Setaria verticillata (L.) P.B.'nin dayanikliliginin saptanmasina yonelik bazi Calismalar.
Demirci, M. and Y. Nemli. 1998. In vitro studies on detection of trifluralin resistance in Setaria verticillata (L.) P.B.: In vitro testlerle trifluraline karsi Setaria verticillata (L.) P.B.'nin dayanikliliginin saptanmasina yonelik bazi Calismalar. Proceedings Second Turkish Weed Science Congress, Bornova, Izmir, Turkey, 1-4 September 1997. : 73-80.
Fate of atrazine in treated and pristine accessions of three Setaria species.
Gimenez Espinosa, R., E. Romera, M. Tena, R. Prado de, and R. De Prado. 1996. Fate of atrazine in treated and pristine accessions of three Setaria species. Pesticide Biochemistry and Physiology. 56: 196-207.
Study of a survey of weed biotypes resistant to atrazine.
Monteiro, I. and F. Rocha. 1992. Study of a survey of weed biotypes resistant to atrazine. Proceedings of the 1992 Congress of the Spanish Weed Science Society. : 315-319.
Mechanism of resistance to atrazine in Setaria verticillata and Setaria faberi.
Prado, R. de, E. Romero, J. Menendez, M. Tena, and R. De Prado. 1992. Mechanism of resistance to atrazine in Setaria verticillata and Setaria faberi. IXe Colloque international sur la biologie des mauvaises herbes, 16-18 September 1992, Dijon, France. : 457-463.
Differential tolerance to atrazine in four Setaria species.
Prado, R. de, M. A. Diaz, and M. Tena. 1990. Differential tolerance to atrazine in four Setaria species. Symposium on integrated weed management in cereals. Proceedings of an EWRS symposium, Helsinki, Finland, 4-6 June 1990. : 61-68.

CONTRIBUTING WEED SCIENTISTS

RAFAEL DE PRADO	Edit
Universidad de Cordoba Qvimica Agricola y Edafologa E T S Ingenieros Agronomos Apartado de Correos 3048 Cordoba, E-14080 Spain Email Rafael De Prado Web : Web Site Link

Acknowledgements

Where to now?

The Herbicide Resistance Action Committee, the Weed Science Society of America, and weed scientists in Spain have been instrumental in providing you this information. Particular thanks is given to Rafael De Prado for providing detailed information.

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