Differential Competitiveness of Sulfonylurea Resistant and Susceptible Prickly Lettuce (Lactuca serriola)

Repeated use of sulfonylurea herbicides in continuous, no-till winter wheat selected for a herbicide resistant biotype of prickly lettuce in Idaho. Greenhouse experiments were conducted to compare the relative competitiveness and growth rate of sulfonylurea herbicide resistant (R) and susceptible (S) prickly lettuce. The S biotype of prickly lettuce produced 31% more aboveground biomass than the R biotype averaged over all densities. Both biotypes were equally competitive when analyzed for both inter- and intrabiotype competition. In relative growth rate studies, regression analysis showed that the S biotype accumulated biomass 52% faster than the R biotype. The results of this study showed that the S biotype was superior to the R biotype in biomass production and growth rate, but competitiveness appeared to be equal for both biotypes. Other fitness parameters must be measured before fitness differences between biotypes can be determined.

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Identification of Sulfonylurea Herbicide-Resistant Prickly Lettuce (Lactuca serriola)

Weed Technology ◽

10.1017/s0890037x00025173 ◽

1990 ◽

Vol 4 (1) ◽

pp. 163-168 ◽

Cited By ~ 170

Author(s):

Carol A. Mallory-Smith ◽

Donald C. Thill ◽

Michael J. Dial

Keyword(s):

Sulfonylurea Herbicides ◽

Sulfonylurea Herbicide ◽

Wheat Field ◽

Herbicide Resistant ◽

Lactuca Serriola ◽

Naturally Occurring ◽

No Till ◽

Prickly Lettuce ◽

Sites Of Action ◽

Imidazolinone Herbicides

A naturally occurring prickly lettuce biotype resistant to a 5:1 formulated mixture of chlorsulfuron:metsulfuron (DPX-G8311) was identified in a no-till winter wheat field near Lewiston, ID, in April, 1987. Field and greenhouse studies were established to evaluate its resistance to other sulfonylureas, imidazolinones, and herbicides with alternate sites of action. The resistant biotype resisted eight sulfonylurea herbicides; resisted the imidazolinone herbicides, imazapyr and imazethypyr, but not imazaquin; and resisted no other herbicides included in the studies. The resistant biotype was identified in seven of nine fields on the farm where it was discovered.

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Monitoring the Occurrence of Sulfonylurea-Resistant Prickly Lettuce (Lactuca serriola)

Weed Technology ◽

10.1017/s0890037x00035016 ◽

1992 ◽

Vol 6 (2) ◽

pp. 437-440 ◽

Cited By ~ 14

Author(s):

Mauricio Alcocer-Ruthling ◽

Donald C. Thill ◽

Carol Mallory-Smith

Keyword(s):

Sulfonylurea Herbicide ◽

Herbicide Resistant ◽

Lactuca Serriola ◽

Prickly Lettuce ◽

Herbicide Use

Sulfonylurea herbicide-resistant prickly lettuce was discovered in Idaho in 1987. The objectives of these surveys were to determine the change with time in the proportion of sulfonylurea resistant and susceptible prickly lettuce biotypes on the farm where it originally occurred, and to determine the spread of sulfonylurea resistant prickly lettuce beyond its point of origin. On average, the proportion of resistant plants had decreased from 1988 to 1990, a period when sulfonylurea herbicide use was discontinued on the farm. Resistant prickly lettuce plants were found at seven sites away from the original infested farm. Several sites were near the farm along roadsides that had been sprayed with sulfometuron. This study shows that the proportion of resistant prickly lettuce decreased where previously found, but its range increased.

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Germination, Growth, and Development of Herbicide Resistant and Susceptible Populations of Rigid Ryegrass (Lolium rigidum)

Weed Science ◽

10.1017/s0043174500093863 ◽

1996 ◽

Vol 44 (2) ◽

pp. 252-256 ◽

Cited By ~ 34

Author(s):

Gurjeet S. Gill ◽

Roger D. Cousens ◽

Margaret R. Allan

Keyword(s):

Growth Rate ◽

Growth And Development ◽

Seedling Emergence ◽

Lolium Rigidum ◽

Relative Growth ◽

Herbicide Resistant ◽

Biological Attributes ◽

The One ◽

Rigid Ryegrass ◽

Susceptible Populations

Rate of seedling emergence, relative growth rate (RGR), and phenological development were compared in several accessions of rigid ryegrass belonging to three distinct resistance classes. The aryloxyphenoxypropionate resistant (AOPP-R) class had a faster and less variable seedling emergence than the sulfonylurea resistant (SU-R) and susceptible (S) classes. However, even the fastest of the AOPP-R accessions was within the range of the S and SU-R classes. No significant differences were detected among the resistant classes in seed dormancy, RGR, and the rate of phenological development. The rate of spike emergence, irrespective of the resistance class, was related to the latitude of the origin of the accessions, suggesting adaptation to the local climates since introduction. Due to considerable variation among weed populations for most biological attributes, the need to include several R and S accessions, in studies similar to the one reported here, is of vital importance. Because of the means and variances of the three resistance classes, at least four accessions from each resistance class would have been required to detect the observed differences between emergence rates of the AOPP-R and S classes with a confidence of 95%.

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Seed Biology of Sulfonylurea-Resistant and -Susceptible Biotypes of Prickly Lettuce (Lactuca serriola)

Weed Technology ◽

10.1017/s0890037x00036381 ◽

1992 ◽

Vol 6 (4) ◽

pp. 858-864 ◽

Cited By ~ 29

Author(s):

Mauricio Alcocer-Ruthling ◽

Donald C. Thill ◽

Bahman Shafii

Keyword(s):

Seed Viability ◽

Soil Surface ◽

Seed Longevity ◽

Herbicide Resistant ◽

Weed Population ◽

Seed Biology ◽

Reproductive Ability ◽

Lactuca Serriola ◽

Prickly Lettuce ◽

Highly Correlated

The persistence of herbicide-resistant biotypes within a given weed population can be highly correlated with the longevity of its seed in the soil and its reproductive ability. This study compared seed longevity of sulfonylurea-susceptible (S) and -resistant (R) biotypes of prickly lettuce in soil at three depths and two locations. Seed longevity in soil was not different between R and S biotypes. Seed longevity was longer when seed were buried compared to seed placed on the soil surface. A field study on seed production showed that prickly lettuce plants produced an average of 14 flower heads and 181 seed per day. Average seed weight was 0.6 mg. No differences were observed in the fecundity or seed viability between the R and S biotypes. However, seed from R biotype plants germinated as fast or faster than seed from S biotype plants.

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