Herbicide Resistant Weeds

GROUP G/9 RESISTANT JOHNSONGRASS (Sorghum halepense)
Argentina

Saturday, July 31, 2010

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Johnsongrass

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

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Introduction

Level of Infestation

Johnsongrass (Sorghum halepense) is a monocot weed in the Poaceae family. In Argentina this weed first evolved resistance to Group G/9 herbicides in 2005 and infests soybean. Group G/9 herbicides are known as Glycines (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.

Local weed scientists estimate that Group G/9 resistant Johnsongrass in Argentina infests 11-50 sites and the number of sites are increasing. They also estimate that there are 10001-100000 acres infested with Group G/9 resistant Johnsongrass and the area infested is increasing.

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 Jul 26, 2006 )
Common Name	Johnsongrass
Species	Sorghum halepense
Group	Glycines (G/9)
Herbicides	glyphosate
Location	Argentina, Province of Salta
Year	2005
Situation(s)	soybean
Sites	11-50
Acres Infested	10001-100000
Contributors	Julio Delucchi
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NOTES ABOUT THIS BIOTYPE

AREAS FOUND

Julio Delucchi

Spots spread in 18,000 to 25,000 acres.

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BIOASSAYS

Julio Delucchi

Resistance confirmed after several field trials & greenhouse tests carried out in 2005 and 2006.

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SPREAD

Julio Delucchi

Resistant Sorghum halepense was found in spots, along 18-20 fields.

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ACADEMIC ASPECTS

Confirmation Tests

Field, and Greenhouse trials comparing a known susceptible Johnsongrass biotype with this Johnsongrass 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

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 Johnsongrass from Argentina please update the database.

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HERBICIDE RESISTANT JOHNSONGRASS GLOBALLY
#	Country	Year	Sites	Acres	Mode of Action
1.	Argentina	2005	11-50	10001-100000	Glycines (G/9)
2.	Argentina	2006	2-5	51-100	Glycines (G/9)
3.	Greece	2005	1	6-10	ACCase inhibitors (A/1)
4.	Israel	2006	1	101-500	ACCase inhibitors (A/1)
5.	Italy	2006	2-5	101-500	ACCase inhibitors (A/1)
6.	Mexico	2009	501-1000	10001-100000	ALS inhibitors (B/2)
7.	USA (Mississippi)	1991	6-10	1001-10000	ACCase inhibitors (A/1)
8.	USA (Kentucky)	1991	1	11-50	ACCase inhibitors (A/1)
9.	USA (Mississippi)	1992	unknown	unknown	Dinitroanilines and others (K1/3)
10.	USA (Tennessee)	1995	2-5	101-500	ACCase inhibitors (A/1)
11.	USA (Virginia)	1995	1	101-500	ACCase inhibitors (A/1)
12.	USA (Louisiana)	1997	1	11-50	ACCase inhibitors (A/1)
13.	USA (Texas)	2000	2-5	11-50	ALS inhibitors (B/2)
14.	USA (Indiana)	2005	2-5	101-500	ALS inhibitors (B/2)
15.	USA (Arkansas)	2007	1	unknown	Glycines (G/9)

FACT SHEETS AND OTHER LITERATURE	Format
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Scientific Abstracts on Herbicide Resistant Sorghum halepense
Experiences in herbicide resistance at the end of this millennium.: Tapasztalatok a herbicid-rezisztenciarol az evezred vegen.
Solymosi, P. 1999. Experiences in herbicide resistance at the end of this millennium.: Tapasztalatok a herbicid-rezisztenciarol az evezred vegen. Novenyvedelem. 35: 485-496.
In vitro expression of variation of glyphosate tolerance in Sorghum halepense.
Kintzios, S., M. Mardikis, K. Passadeos, and G. Economou. 1999. In vitro expression of variation of glyphosate tolerance in Sorghum halepense. Weed Research. 39: 49-55.
Physiological basis for nicosulfuron and primisulfuron selectivity in five plant species.
Carey, J. B., D. Penner, and J. J. Kells. 1997. Physiological basis for nicosulfuron and primisulfuron selectivity in five plant species. Weed Science. 45: 22-30.
Identification of graminicide-resistant johnsongrass (Sorghum halepense).
Smeda, R. J., C. E. Snipes, and W. L. Barrentine. 1997. Identification of graminicide-resistant johnsongrass (Sorghum halepense). Weed Science. 45: 132-137.
Spot-treating johnsongrass in corn with Accent R and Beacon R.
Hurst, H. R. and J. E. Street. 1995. Spot-treating johnsongrass in corn with Accent R and Beacon R. Herbicide-resistant crops: a bitter or better harvest? Proceedings of the 48th annual meeting of the Southern Weed Science Society, Memphis, Tennessee, USA, 16-18 January 1995. : 18-30.
Target site-based resistance to herbicides inhibiting acetyl-CoA carboxylase.
Tardif, F. J. and S. B. Powles. 1993. Target site-based resistance to herbicides inhibiting acetyl-CoA carboxylase. Brighton crop protection conference, weeds. Proceedings of an international conference, Brighton, UK, 22-25 November 1993. 2: 533-540.
Documentation of graminicide [fluazifop-P, sethoxydim, quizalofop, quizalofop-P and clethodim]-resistant johnsongrass [Sorghum halepense] in cotton [grown in Mississippi, USA].
Snipes, C. E., W. L. Barrentine, and R. J. Smeda. 1993. Documentation of graminicide [fluazifop-P, sethoxydim, quizalofop, quizalofop-P and clethodim]-resistant johnsongrass [Sorghum halepense] in cotton [grown in Mississippi, USA]. Proceedings, Beltwide Cotton Conferences, 10-14 January 1993, New Orleans, Louisiana, USA. : 1508.
Herbicide resistance confirmed in johnsongrass biotypes.
Barrentine, W. L., C. E. Snipes, and R. J. Smeda. 1992. Herbicide resistance confirmed in johnsongrass biotypes. Research Report Mississippi Agricultural and Forestry Experiment Station. 17: 5.
Combination of new herbicides for weed control along roadsides.
Nir, A. and A. Raz. 1988. Combination of new herbicides for weed control along roadsides. Phytoparasitica. 16: 386-387.
Some effects of the herbicide fluazyfop-butyl on the physiology of johnsongrass (Sorghum halepense (L.) Pers.).
Magallanes, M. E., G. Ortiz, and M. Rojas Garciduenas. 1986. Some effects of the herbicide fluazyfop-butyl on the physiology of johnsongrass (Sorghum halepense (L.) Pers.). Turrialba. 36: 469-472.

CONTRIBUTING WEED SCIENTISTS

JULIO DELUCCHI	Edit
PD & Tech Services Manager Monsanto Argentina SAIC Maipú 1210 Buenos Aires, C 1006 ACT Argentina Email Julio Delucchi

Acknowledgements

Where to now?

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

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