A Putative Prodiamine-Resistant Annual Bluegrass (Poa annua) Population is Controlled by Indaziflam

Weed Science ◽  
2014 ◽  
Vol 62 (1) ◽  
pp. 138-144 ◽  
Author(s):  
James T. Brosnan ◽  
Eric H. Reasor ◽  
Jose J. Vargas ◽  
Gregory K. Breeden ◽  
Dean A. Kopsell ◽  
...  
Keyword(s):  
Root Growth ◽  
Acetolactate Synthase ◽  
Field Trials ◽  
Golf Course ◽  
Future Research ◽  
Cellulose Biosynthesis ◽  
Susceptible Population ◽  
Annual Bluegrass ◽  
The Past ◽  
Whole Plant

Prodiamine is a mitotic inhibiting herbicide regularly used to control annual bluegrass PRE. A population of annual bluegrass not controlled by prodiamine at 1,120 g a.i. ha−1was identified on a golf course in Alcoa, TN, in 2012. A whole-plant hydroponics bioassay was used to screen this biotype for prodiamine resistance (PR) compared with a known susceptible population (SS). Multitiller (i.e., > 4 tillers) PR and SS annual bluegrass plants were established in hydroponic culture and exposed to 0, 0.001, 0.01, 0.10, 1.0, and 10.0 mM prodiamine. Exposure to prodiamine at 0.001 mM reduced root growth of the SS biotype to 26% of the nontreated check (i.e., 0 mM prodiamine) but had no effect on the PR biotype. When exposed to 10 mM prodiamine, root growth of the PR biotype was reduced to 24% of the nontreated check compared with 9% for the SS biotype.I50values for the PR and SS biotypes were 0.04 and 2.8 × 10−6mM prodiamine, respectively. The PR biotype measured lower in plant height and leaf width than the SS population. In field trials, prodiamine at 560, 840, 1,120, and 1,400 g ha−1only controlled the PR biotype 0 to 22%. PRE applications of the cellulose biosynthesis inhibitor indaziflam at 35, 52.5, and 70 g a.i. ha−1controlled this PR biotype 70 to 97%. This marks the second instance of annual bluegrass developing resistance to prodiamine in Tennessee during the past 5 yr. Future research should evaluate indaziflam efficacy for control of other prodiamine-resistant biotypes of annual bluegrass as well as annual bluegrass biotypes resistant to herbicidal inhibitors of 5-enolpyruvylshikimic acid-3-phosphate synthase, acetolactate synthase, and photosystem II.

A Trp574 to Leu Amino Acid Substitution in the ALS Gene of Annual Bluegrass (Poa annua) Is Associated with Resistance to ALS-Inhibiting Herbicides

Weed Science ◽  
2013 ◽  
Vol 61 (1) ◽  
pp. 21-25 ◽  
Author(s):  
J. Scott McElroy ◽  
Michael L. Flessner ◽  
Zhuoyu Wang ◽  
Fenny Dane ◽  
Robert H. Walker ◽  
...  
Keyword(s):  
Amino Acid ◽  
Point Mutation ◽  
Amino Acid Substitution ◽  
Acetolactate Synthase ◽  
Poa Annua ◽  
Golf Course ◽  
Missense Mutations ◽  
Gene Sequences ◽  
Susceptible Population ◽  
Annual Bluegrass

Annual bluegrass is commonly controlled by acetolactate synthase (ALS)-inhibiting herbicides in managed turfgrass. An annual bluegrass population with suspected resistance to ALS-inhibiting herbicides was collected from Grand National Golf Course in Opelika, AL (GN population). Subsequent testing confirmed resistance of the GN population to foramsulfuron, trifloxysulfuron, bispyribac-sodium (bispyribac), and imazaquin when compared to a susceptible population collected locally at Auburn University (AU population). Sequencing of the ALS gene revealed a point mutation resulting in an amino acid substitution at Trp574. Cloning of the ALS gene surrounding the Trp574 region yielded two distinct ALS gene sequences: one producing Trp574 and one producing Leu574. Trp574 to Leu has been previously correlated with resistance to ALS-inhibiting herbicides. Both AU and GN gene sequences contained other similar silent and missense mutations. This research confirms resistance of annual bluegrass to ALS-inhibiting herbicides with Trp574 to Leu amino acid substitution being the most likely mode of resistance based on past literature.

A Pro106to Ala Substitution is Associated with Resistance to Glyphosate in Annual Bluegrass (Poa annua)

Weed Science ◽  
2015 ◽  
Vol 63 (3) ◽  
pp. 613-622 ◽  
Author(s):  
Robert B. Cross ◽  
Lambert B. McCarty ◽  
Nishanth Tharayil ◽  
J. Scott McElroy ◽  
Shu Chen ◽  
...  
Keyword(s):  
South Carolina ◽  
Warm Season ◽  
Glyphosate Resistance ◽  
Golf Course ◽  
Epsp Synthase ◽  
Annual Bluegrass ◽  
Whole Plant ◽  
Treated Leaf ◽  
Plant Level ◽  
Root Tissues

Glyphosate is used in the transition zone to control annual bluegrass in fully dormant warm-season grasses. A suspected resistant (R) biotype of annual bluegrass was identified on a golf course in South Carolina after at least 10 consecutive years of glyphosate application. Greenhouse bioassays revealed the R biotype was 4.4-fold resistant to glyphosate compared with a standard susceptible (S) biotype. Further studies were conducted to investigate the mechanism conferring glyphosate resistance in the R biotype. Leaf discs of both biotypes accumulated shikimate in response to increasing glyphosate concentration, but the glyphosate concentration resulting in 50% EPSP synthase inhibition as a result of shikimate accumulation (I50) was 4.2-fold higher in the R biotype compared with the S biotype. At the whole plant level, similar levels of shikimate accumulation were observed between biotypes at 6 and 24 h after treatment (HAT) with glyphosate, but greater shikimate accumulation occurred in the S biotype at 72, 120, and 168 HAT. Shikimate levels decreased in the R biotype after 72 HAT. There were no differences in14C-glyphosate absorption between biotypes. However, more14C-glyphosate translocated out of the treated leaf in the R biotype and into root tissues over time compared with the S biotype. Partial sequencing of the EPSP synthase gene revealed a point mutation that resulted in an Ala substitution at Pro106. Although other mechanisms may contribute to glyphosate resistance, these results confirm a Pro106to Ala substitution is associated with resistance to glyphosate in the R annual bluegrass biotype.

A Glyphosate-Resistant Biotype of Annual Bluegrass in Tennessee

Weed Science ◽  
2012 ◽  
Vol 60 (1) ◽  
pp. 97-100 ◽  
Author(s):  
James T. Brosnan ◽  
Gregory K. Breeden ◽  
Thomas C. Mueller
Keyword(s):  
Untreated Control ◽  
Laboratory Experiments ◽  
Photochemical Efficiency ◽  
Resistance Factor ◽  
Golf Course ◽  
Future Research ◽  
Annual Bluegrass ◽  
Modes Of Action

Glyphosate is regularly used to control annual bluegrass populations in dormant bermudagrass turf. A population of annual bluegrass not controlled by glyphosate at 840 g ha−1(glyphosate resistant, GR) was identified on a golf course in Humboldt, TN in 2010. Mature tillers of GR plants were established in a greenhouse and treated with glyphosate at 0, 210, 420, 840, 1,680, 3,360, and 6,720 g ha−1. Mature tillers of a biotype known to be susceptible to glyphosate (SS) were also established in the greenhouse and subjected to the same treatments. At 14 d after treatment (DAT), glyphosate controlled the SS biotype > 95% at rates > 420 g ha−1. Comparatively, the GR biotype was only controlled 76% with glyphosate at 6,720 g ha−1. The rates required to provide 50% control (I50values) for SS and GR biotypes were 236 and 2,812 g ha−1respectively, resulting in a resistance factor of 12. Photochemical efficiency (Fv/Fm) values on SS plants treated with glyphosate at > 210 g ha−1measured 0.000 at 14 DAT, whereasFv/Fmvalues on GR plants were not significantly different from the untreated control with glyphosate rates ≤ 840 g ha−1on the same date. In laboratory experiments, the SS biotype accumulated greater shikimate concentrations than the GR biotype 3 to 6 DAT. Future research should evaluate strategies for managing GR and SS annual bluegrass with alternative modes of action.

Detecting Annual Bluegrass (Poa annua) Resistance to ALS-Inhibiting Herbicides Using a Rapid Diagnostic Assay

Weed Science ◽  
2013 ◽  
Vol 61 (3) ◽  
pp. 384-389 ◽  
Author(s):  
Robert B. Cross ◽  
Lambert B. McCarty ◽  
Nishanth Tharayil ◽  
Ted Whitwell ◽  
William C. Bridges
Keyword(s):  
South Carolina ◽  
Dose Response ◽  
Acetolactate Synthase ◽  
Shoot Biomass ◽  
Future Research ◽  
Clemson University ◽  
Herbicide Resistant ◽  
Annual Bluegrass ◽  
Als Inhibitors

Annual bluegrass is the most problematic winter annual weed in managed turfgrass. Acetolactate synthase (ALS)-inhibiting herbicides are effective for annual bluegrass control, but reliance on this mode of action can select for herbicide-resistant biotypes. Two annual bluegrass biotypes not controlled with ALS-inhibiting herbicides were reported at golf courses in South Carolina and Georgia. Research was initiated at Clemson University to verify the level of resistance of these biotypes to ALS inhibitors. Two ALS-susceptible (S) and suspected resistant (SCr, GAr) annual bluegrass biotypes were established in a greenhouse. Dose-response experiments were conducted on mature annual bluegrass plants using trifloxysulfuron, foramsulfuron, and bispyribac-sodium, all ALS-inhibiting herbicides. Additionally, a rapid diagnostic ALS activity assay was optimized and conducted using the same herbicides. For dose-response experiments, the rate of herbicide that reduced shoot biomass 50% (I50) values for the S biotypes were 13.6 g ai ha−1for trifloxysulfuron, 7.0 g ai ha−1for foramsulfuron, and 38.3 g ai ha−1for bispyribac-sodium. Fifty percent shoot biomass reduction was not observed in either the SCr or GAr biotypes at eight times the labeled field rate of all ALS-inhibiting herbicides tested. For in vivo tests of ALS activity, the SCr biotype yielded I50(concentration of herbicide that reduced ALS activity 50%) values 3,650, 3,290, and 13 times the S biotypes following treatment with trifloxysulfuron, foramsulfuron, and bispyribac-sodium, respectively. Similarly, I50values for the GAr biotype were 316, 140, and 64 times greater than the S biotypes following the same herbicide treatments. This research indicates high levels of annual bluegrass resistance to multiple ALS-inhibiting herbicides in South Carolina and Georgia. Future research should focus on the mechanisms of ALS resistance in these annual bluegrass biotypes as well as alternative options for control not targeting the ALS enzyme.

Molecular Basis of Resistance to Tribenuron in Water Starwort (Myosoton aquaticum) Populations from China

Weed Science ◽  
2013 ◽  
Vol 61 (3) ◽  
pp. 390-395 ◽  
Author(s):  
Weitang Liu ◽  
Yaling Bi ◽  
Lingxu Li ◽  
Guohui Yuan ◽  
Jinxin Wang
Keyword(s):  
Molecular Basis ◽  
Inhibitory Concentration ◽  
Acetolactate Synthase ◽  
Susceptible Population ◽  
Documented Case ◽  
Whole Plant ◽  
Winter Annual ◽  
High Level ◽  
Plant Bioassays

Populations of water starwort, a winter annual or biennial weed in the pink family (Caryophyllaceae), can no longer be controlled by tribenuron following successive use of this herbicide over several years. Whole-plant bioassays have established that the resistant water starwort populations JS17, JS08, JS16, and JS07 showed high-level (from 203-fold to 565-fold) resistance to tribenuron. In vitro acetolactate synthase (ALS) assays revealed that resistance was due to reduced sensitivity of the ALS enzyme to tribenuron. The half-maximal inhibitory concentration (I50) values for JS17, JS08, JS16, and JS07 were 72, 71, 70, and 76 times greater, respectively, than were those of the susceptible population JS24. This altered ALS sensitivity in the resistant populations was due to a mutation in the ALS gene resulting in a Pro197to Ser substitution (JS17, JS08, and JS16) and a Pro197to Leu substitution (JS07). This study established the first documented case, to our knowledge, of evolved tribenuron resistance in water starwort and concluded that the molecular basis of resistance is due, at least in part, to a target-site modification at Pro197in the ALS gene.

A Biotype of Annual Bluegrass (Poa annua) in Tennessee Is Resistant to Inhibitors of ALS and Photosystem II

Weed Science ◽  
2015 ◽  
Vol 63 (1) ◽  
pp. 321-328 ◽  
Author(s):  
James T. Brosnan ◽  
Gregory K. Breeden ◽  
Jose J. Vargas ◽  
Logan Grier
Keyword(s):  
United States ◽  
Photosystem Ii ◽  
Herbicide Resistance ◽  
Dose Response ◽  
Southeastern United States ◽  
Acetolactate Synthase ◽  
Poa Annua ◽  
Annual Bluegrass ◽  
Leaf Stage ◽  
Whole Plant

Annual bluegrass resistance to inhibitors of acetolactate synthase (ALS) and photosystem II (PSII) in managed turf has been confirmed in the southeastern United States. A biotype of annual bluegrass that had developed resistance (R) to the PSII inhibitor simazine was not controlled by POST applications of foramsulfuron or trifloxysulfuron in 2011 or 2012. In whole plant dose-response experiments, trifloxysulfuron, simazine, and indaziflam controlled a susceptible (S) population of annual bluegrass > 91% when applied POST to nontillering plants. However, trifloxysulfuron applications at 3.5 to 223 g ai ha−1only controlled R annual bluegrass ≤ 40%. Similarly, simazine at 140 to 9,000 g ai ha−1only controlled R annual bluegrass ≤ 20%. R annual bluegrass plants were more tolerant to indaziflam applied POST to leaf stage plants prior to tillering, as rates > 100 g ai ha−1were needed to control R annual bluegrass ≥ 96%. No differences in the activity of ALS in R and S plants exposed to increasing foramsulfuron concentrations from 0 to 100 µM were detected suggesting that nontarget mechanisms could explain reduced efficacy of POST herbicide applications in whole plant dose-response experiments. Applications of indaziflam (35 to 70 g ha−1) and oxadiazon (2,240 to 4,500 g ai ha−1) effectively controlled R annual bluegrass when applied PRE. This biotype of R annual bluegrass is the first reported instance of a weed developing resistance to multiple modes of action in managed turf. Education is needed among turf managers regarding the consequences of exclusive use of the same herbicides for annual bluegrass control leading to the onset of herbicide resistance.

Creeping Bentgrass (Agrostis stolonifera) Golf Green Tolerance to Bispyribac-Sodium Tank-Mixed with Paclobutrazol

2012 ◽  
Vol 26 (1) ◽  
pp. 145-150 ◽  
Author(s):  
Justin Q. Moss ◽  
Xi Xiong ◽  
Kemin Su ◽  
Bishow P. Poudel ◽  
John B. Haguewood
Keyword(s):  
Creeping Bentgrass ◽  
Field Trials ◽  
Agrostis Stolonifera ◽  
Golf Course ◽  
Putting Greens ◽  
Annual Bluegrass ◽  
Turf Quality ◽  
Putting Green ◽  
Zone Field ◽  
Weekly Application

Annual bluegrass is a troublesome weed in golf course putting greens. The objective of this research was to evaluate creeping bentgrass putting green tolerance to bispyribac-sodium tank-mixed with paclobutrazol in the transition zone. Field trials with four replications were conducted in Oklahoma during 2009 and 2010 and in Missouri during 2010. The results of this study suggest that tank-mixing bispyribac-sodium with paclobutrazol may discolor creeping bentgrass putting greens but will not reduce turf quality below acceptable levels. Normalized vegetative difference index readings indicated no treatment differences in turf greenness at 4 and 8 wk after initial treatment. Weekly application of bispyribac-sodium at 12.4 g ha−1 or biweekly application at 24.8 g ha−1 alone or with monthly applications of paclobutrazol at 224 g ha−1 did not cause unacceptable injury to creeping bentgrass putting greens during the spring.

scholarly journals Controlling Annual Bluegrass (Poa annua L.) Summer Patch Disease with Faeriefungin

HortScience ◽  
1993 ◽  
Vol 28 (3) ◽  
pp. 195-196
Author(s):  
Brad P. Melvin ◽  
Muraleedharan G. Nair ◽  
Joe M. Vargas ◽  
A. Ronald Detweiler
Keyword(s):  
Streptomyces Griseus ◽  
Field Trials ◽  
Poa Annua ◽  
Golf Course ◽  
Annual Bluegrass ◽  
Magnaporthe Poae ◽  
History Of ◽  
Patch Disease

Faeriefungin, an antibiotic produced by the actinomycete Streptomyces griseus var. autotrophicus MSU-32058/ATCC 53668, was tested in field trials on golf course fairways to determine if it could control annual bluegrass (Poa annua L.) summer patch effectively. Test sites with a history of severe summer patch outbreaks caused by Magnaporthe poae Landschoot and Jackson were chosen for study. Faeriefungin, when applied as a drench at 0.74 kg·ha-1, effectively controlled summer patch and was not significantly different than the fungicide fenarimol in three of four field trials. Faeriefungin may be an alternative to chemically controlling summer patch disease.

scholarly journals Postemergence Weed Control in Warm-season Turfgrass with a Mixture of Pyrimisulfan and Penoxsulam

HortScience ◽  
2019 ◽  
Vol 54 (5) ◽  
pp. 960-963 ◽  
Author(s):  
James T. Brosnan ◽  
Gregory K. Breeden
Keyword(s):  
Weed Control ◽  
White Clover ◽  
Festuca Arundinacea ◽  
Cynodon Dactylon ◽  
Warm Season ◽  
Acetolactate Synthase ◽  
Field Trials ◽  
Future Research ◽  
Yellow Nutsedge ◽  
Virginia Buttonweed

Pyrimisulfan is a sulfonanilide herbicidal inhibitor of acetolactate synthase (ALS) used to control grass and sedge weeds of rice (Oryza stricta L.) production. Penoxsulam is an ALS-inhibiting herbicide that provides early postemergence control of broadleaf weeds in managed turfgrass. Separate field trials were conducted in Knoxville, TN, during Summer 2017 and 2018 to evaluate the efficacy of pyrimisulfan + penoxsulam for control of white clover (Trifolium repens L.), yellow nutsedge (Cyperus esculentus L.), wild violet (Viola spp.), ground ivy (Glechoma hederacea L.), and virginia buttonweed (Diodia virginiana L.) in common bermudagrass (Cynodon dactylon L.) and tall fescue (Festuca arundinacea Schreb.) turf. All treatments were applied on a granular fertilizer carrier (mean particle size, 1.5 mm) that contained 21% N : 0% P2O5 : 3% K2O. Treatments were applied at an early postemergence growth stage during April of each year and were irrigated into the soil within 24 hours of application. Weed control was assessed from 4 to 10 weeks after initial treatment (WAIT) relative to untreated control plots in each replication. White clover and wild violet were controlled effectively with pyrimisulfan + penoxsulam at 70 + 70 g·ha−1 whereas sequential applications at either 70 + 70 g·ha−1 followed by 35 + 35 g·ha−1 or 52.5 + 52.5 g·ha−1 followed by 52.5 + 52.5 g·ha−1 were needed to control yellow nutsedge, ground ivy, and virginia buttonweed effectively. Future research should explore long-term control of these species, particularly wild violet, ground ivy, and virginia buttonweed with pyrimisulfan + penoxsulam applied over multiple seasons. Chemical names: 2′-[(4,6-dimethoxypyrimidin-2-yl)(hydroxy) methyl]-1,1-difluoro-6′-(methoxymethyl)methanesulfonanilide (pyrimisulfan); 2-(2,2-difluoroethoxy)-N-(5,8-dimethoxy1,2,4triazolo 1.5-c-pyrimidin-2-yl)-6-(trifluoromethyl)benzenesulfonamide (penoxsulam).

scholarly journals Confirmation of Glyphosate- and Acetolactate Synthase (ALS)-Inhibitor-Resistant Kochia (Kochia scoparia) in Nebraska

2016 ◽  
Vol 8 (10) ◽  
pp. 54
Author(s):  
Neha Rana ◽  
Amit J. Jhala
Keyword(s):  
Great Plains ◽  
Acetolactate Synthase ◽  
The United States ◽  
Future Research ◽  
Kochia Scoparia ◽  
Whole Plant ◽  
Fold Level ◽  
Evolution Of Resistance ◽  
Resistance To Herbicides ◽  
Als Inhibitor

<p>Kochia is an early emerging weed of increasing concern across the Great Plains region of the United States due to the evolution of resistance to herbicides. Greenhouse studies were conducted to confirm and characterize the level of glyphosate and acetolactate synthase (ALS)-inhibiting herbicide resistance in kochia biotype collected from a field in Sheridan County in Nebraska. The response of kochia biotype to 9 rates (0 to 16×) of tribenuron and glyphosate was evaluated in a whole plant dose-response bioassay. On the basis of the values at the 90% effective dose (ED<sub>90</sub>), the putative-resistant kochia biotype had a 6- and 15-fold level of resistance to glyphosate and tribenuron, respectively. Future research will evaluate strategies for the management of glyphosate- and ALS-resistant kochia under field conditions.</p>

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