Herbicide Resistant Weeds

GROUP B/2 RESISTANT PERENNIAL RYEGRASS (Lolium perenne)
USA: Texas

Saturday, July 31, 2010

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Perennial Ryegrass

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

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Introduction

Level of Infestation

Perennial Ryegrass (Lolium perenne) is a monocot weed in the Poaceae family. In Texas this weed first evolved resistance to Group B/2 herbicides in 1989 and infests roadsides. Group B/2 herbicides are known as ALS inhibitors (Inhibition of acetolactate synthase ALS (acetohydroxyacid synthase AHAS)). Research has shown that these particular biotypes are resistant to sulfometuron-methyl and they may be cross-resistant to other Group B/2 herbicides.

Local weed scientists estimate that Group B/2 resistant Perennial Ryegrass in Texas infests 2-5 sites. They also estimate that there are 51-100 acres infested with Group B/2 resistant Perennial Ryegrass.

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 Sep 15, 2000 )
Common Name	Perennial Ryegrass
Species	Lolium perenne
Group	ALS inhibitors (B/2)
Herbicides	sulfometuron-methyl
Location	USA, Texas
Year	1989
Situation(s)	roadsides
Sites	2-5
Acres Infested	51-100
Contributors	Leonard Saari
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NOTES ABOUT THIS BIOTYPE

GENERAL

Leonard Saari

Selection agent was sulfometuron/chlorsulfuron

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GENERAL

Leonard Saari

Saari, L. L.; Cotterman, J. C.; Smith, W. F., and Primiani, M. M. 1992. Sulfonylurea herbicide resistance in common chickweed, perennial ryegrass, and Russian thistle. Pesticide Biochemistry and Physiology. 42(2):110-118.

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ACADEMIC ASPECTS

Confirmation Tests

Laboratory trials comparing a known susceptible Perennial Ryegrass biotype with this Perennial Ryegrass 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 B/2 resistant Perennial Ryegrass from Texas please update the database.

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HERBICIDE RESISTANT PERENNIAL RYEGRASS GLOBALLY
#	Country	Year	Sites	Acres	Mode of Action
1.	Argentina	2008	2-5	11-50	Glycines (G/9)
2.	Chile	2001	2-5	101-500	ACCase inhibitors (A/1)
3.	Germany Multiple Resistance	2008	1	6-10	ACCase inhibitors (A/1) ALS inhibitors (B/2)
4.	USA (California)	1989	1	1-5	ALS inhibitors (B/2)
5.	USA (Texas)	1989	2-5	51-100	ALS inhibitors (B/2)

FACT SHEETS AND OTHER LITERATURE	Format
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Scientific Abstracts on Herbicide Resistant Lolium perenne
Relative intra-species competitive ability of nodding thistle biotypes with varying resistance to the herbicide 2,4-D.
Bonner, K. I., A. Rahman, T. James K., K. Nicholson S., and D. Wardle A. 1998. Relative intra-species competitive ability of nodding thistle biotypes with varying resistance to the herbicide 2,4-D. New Zealand Journal of Agricultural Research. 41: 291-297.
The inheritance of chlorsulfuron resistance in perennial ryegrass: strategic implications for management of resistance.
Mackenzie, R., A. M. Mortimer, P. D. Putwain, I. B. Bryan, and T. R. Hawkes. 1995. The inheritance of chlorsulfuron resistance in perennial ryegrass: strategic implications for management of resistance. Brighton crop protection conference: weeds. Proceedings of an international conference, Brighton, UK, 20-23 November 1995. 2: 769-774.
The evolution of herbicide resistance: deliberate selection for chlorsulfuron resistance in perennial ryegrass.
MacKenzie, R., A. M. Mortimer, P. D. Putwain, I. B. Bryan, and T. R. Hawkes. 1993. The evolution of herbicide resistance: deliberate selection for chlorsulfuron resistance in perennial ryegrass. Brighton crop protection conference, weeds. Proceedings of an international conference, Brighton, UK, 22-25 November 1993. 2: 645-646.
Sulfonylurea herbicide resistance in common chickweed, perennial ryegrass, and Russian thistle.
Saari, L. L., J. C. Cotterman, W. F. Smith, and M. M. Primiani. 1992. Sulfonylurea herbicide resistance in common chickweed, perennial ryegrass, and Russian thistle. Pesticide Biochemistry and Physiology. 42: 110-118.
Cross tolerance to herbicidal and environmental oxidants of plant biotypes tolerant to paraquat, sulfur dioxide, and ozone.
Shaaltiel, Y., A. Glazer, P. F. Bocion, and J. Gressel. 1988. Cross tolerance to herbicidal and environmental oxidants of plant biotypes tolerant to paraquat, sulfur dioxide, and ozone. Pesticide Biochemistry and Physiology. 31: 13-23.
Mechanism of paraquat tolerance in Conyza bonariensis and in Lolium perenne.
Shaaltiel, Y. and J. Gressel. 1985. Mechanism of paraquat tolerance in Conyza bonariensis and in Lolium perenne. Phytoparasitica. 13: 232.
Herbicide resistance in plants - future research needs.
LeBaron, H. M. 1984. Herbicide resistance in plants - future research needs. Weeds Today. 15: 2-5.

CONTRIBUTING WEED SCIENTISTS

LEONARD SAARI	Edit
Manager, Technology Transfer & Licensing E.I. DuPont deNemours Company Central Research and Development P.O. Box 80328 Wilmington, 19880-0328, Delaware USA Email Leonard Saari

Acknowledgements

Where to now?

The Herbicide Resistance Action Committee, The North American Herbicide Resistance Action Committee, the Weed Science Society of America, and weed scientists in Texas have been instrumental in providing you this information. Particular thanks is given to Leonard Saari for providing detailed information.

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