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.

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.

Evaluation of Oriental Mustard (Brassica juncea) Seed Meal for Weed Suppression in Turf

2010 ◽  
Vol 24 (4) ◽  
pp. 440-445 ◽  
Author(s):  
Daniel T. Earlywine ◽  
Reid J. Smeda ◽  
Travis C. Teuton ◽  
Carl E. Sams ◽  
Xi Xiong
Keyword(s):  
Perennial Ryegrass ◽  
White Clover ◽  
Tall Fescue ◽  
Methyl Bromide ◽  
Untreated Control ◽  
Seed Meal ◽  
Mustard Seed ◽  
Annual Bluegrass ◽  
Oriental Mustard ◽  
Large Crabgrass

Oriental mustard seed meal (MSM), a byproduct generated by pressing the seed for oil, exhibits herbicidal properties. In turfgrass, soil fumigants such as methyl bromide are used to control weeds prior to renovation of turf. Environmental concerns have resulted in deregistration of methyl bromide, prompting the need for alternatives. The objective of this research was to determine the effect of MSM on the establishment of selected turfgrass weeds as well as inhibitory effects on establishment of desirable turfgrasses. Greenhouse experiments were conducted in 2006 and 2007 at the University of Missouri. MSM was amended in soil at 0, 1,350 (low), 2,350 (medium), and 3,360 kg ha−1(high) concentrations. Weed species included annual bluegrass, large crabgrass, buckhorn plantain, white clover, and common chickweed. Turfgrass species included: Rembrandt tall fescue, Evening Shade perennial rye, and Riviera bermudagrass. All species were seeded into soil amended with MSM and either tarped or left untarped. All treatments were compared to dazomet (392 kg ha−1), a synthetic standard. Plant counts and biomass of all species were recorded 4 wk after seeding. Overall, tarped treatments suppressed weed emergence 27 to 50% more compared to untarped treatments, except for large crabgrass. High rates of MSM suppressed emergence of all weeds ≥ 63%. Compared to the untreated control, the density of buckhorn plantain, white clover, and common chickweed was reduced by ≥ 42% at low rates of MSM. Biomass of buckhorn plantain, annual bluegrass, common chickweed, white clover, and large crabgrass was reduced from 37 to 99% at high rates of MSM. MSM at high rates reduced stand counts of tall fescue and perennial ryegrass up to 81% and 77% respectively, compared to the untreated control. Regardless of MSM rates or tarping, suppression of common bermudagrass emergence did not exceed 30%; tarped treatments actually increased bermudagrass emergence by 22%. The biomass for tall fescue, perennial ryegrass, and bermudagrass was reduced by 85, 68, and 10%, respectively, at high rates of MSM. For tall fescue, MSM at all rates strongly suppressed seed germination by 7 d after planting (DAP) (up to 100%), with additional germination observed through 14 DAP, but not thereafter. In both trials, dazomet completely suppressed emergence of all weeds. MSM appears to suppress emergence and growth of a number of weeds common in turf, with potential selectivity for bermudagrass.

Judgment Based Marketing Decision Models: Problems and Possible Solutions

1981 ◽  
Vol 45 (4) ◽  
pp. 13-23 ◽  
Author(s):  
Dipankar Chakravarti ◽  
Andrew Mitchell ◽  
Richard Staelin
Keyword(s):  
Decision Making ◽  
Comparative Analysis ◽  
Laboratory Experiments ◽  
Field Studies ◽  
Decision Models ◽  
Future Research ◽  
Marketing Decision ◽  
Recent Laboratory

This paper presents a comparative analysis of the findings of two field studies and three recent laboratory experiments that assessed the efficacy of judgment based models in aiding marketing decision making. This analysis indicates factors that may affect the effectiveness of these models. The implications of the findings for users of judgment based marketing decision models as well as model builders are discussed, and suggestions are made for future research to improve the models’ effectiveness.

scholarly journals Control of the Black Turfgrass Ataenius Larvae on a Golf Course Fairway 1994

1995 ◽  
Vol 20 (1) ◽  
pp. 273-274
Author(s):  
K. T. Power ◽  
D. J. Shetlar ◽  
H. D. Niemczyk ◽  
M. G. Belcher
Keyword(s):  
Granular Materials ◽  
Environmental Conditions ◽  
Golf Course ◽  
Efficacy Data ◽  
Annual Bluegrass ◽  
Experimental Area ◽  
Water Ph

Abstract The study was located on golf course fairway at Seville. Insecticides were applied 23 Jul to plots 10 × 10 ft (3.1 × 3.1 m) arranged in a RCB, replicated 4 times. Granular materials were applied using a drop spreader and shaker jar. Liquid treatments were applied with a CO2 sprayer with Teejet XR8008VS nozzles at 35 psi (2.46 kg/cm2) pressure that delivered a volume of 1 gal/1000 ft2 (407 liter/ha) and pythrethriods with a CO2 sprayer with Teejet 8010 nozzles at 35 psi (2.46 kg/cm2) pressure that delivered a volume of 2 gal/1000 ft2 (814 liter/ha). The experimental area was irrigated approximately V* inch (6 mm) of water using the golf course system. Environmental conditions at time of treatment were as follows. BTA: eggs, 1st and 2nd instars present, 60 larvae/ ft2. Turf: level, dry, 5A inch (16 mm) height, 70% bentgrass and 30% annual bluegrass. Thatch: dense, moist, % inch (2 cm). Soil, moist, 74°F at 1 inch (2.5 cm) and 72°F at 3 inch (7.6 cm). Weather: sunny, 81°F, 0 mph. Water: pH 4.6. Efficacy data taken 7 Jul (14 DAT) were based on the number of live larvae in six samples 4% inch (10.8 cm) in diam from each plot.

Annual Bluegrass (Poa annua) Biotypes Exhibit Differential Levels of Susceptibility and Biochemical Responses to Protoporphyrinogen Oxidase Inhibitors

Weed Science ◽  
2018 ◽  
Vol 66 (5) ◽  
pp. 574-580 ◽  
Author(s):  
Jialin Yu ◽  
Patrick E. McCullough ◽  
Mark A. Czarnota
Keyword(s):  
Lipid Peroxidation ◽  
Electrolyte Leakage ◽  
Laboratory Experiments ◽  
Physiological Responses ◽  
Poa Annua ◽  
Shoot Biomass ◽  
Protoporphyrinogen Oxidase ◽  
Annual Bluegrass ◽  
Biochemical Responses ◽  
Inhibitor Resistance

AbstractAn annual bluegrass (Poa annuaL.) biotype with limited susceptibility to POST flumioxazin applications was identified in Georgia. The objectives of this research were to quantify tolerance levels of this biotype (R-biotype) to protoporphyrinogen oxidase (PPO) inhibitors and characterize physiological responses to flumioxazin. In dose–response experiments on 3- to 5-tiller plants, flumioxazin and sulfentrazone rates required to reduce dry-shoot biomass 50% from the nontreated were >14.5 and 10.4 times greater for the R-biotype, as compared with a susceptible (S)-biotype, respectively. Establishment of the R-biotype from seed was completely controlled by PRE applications of flumioxazin and oxadiazon, similar to the S-biotype. Tank mixtures of chlorpyrifos with flumioxazin did not enhance biomass reductions of the R-biotype, suggesting that tolerance levels may not be related to cytochrome P450–associated metabolism. In laboratory experiments, the R-biotype averaged 27% less electrolyte leakage, as compared with the S-biotype, after flumioxazin treatments. Lipid peroxidation in the R-biotype, as measured by malondialdehyde levels, averaged 25% less than the S-biotype at 72 h after broadcast flumioxazin treatments at 280 and 560 g ha−1. The tolerance to POST applications of PPO inhibitors in thisP. annuabiotype is associated with less lipid peroxidation and electrolyte leakage as compared with the S-biotype. These biochemical differences in biotypes may contribute to erratic levels of POST control from flumioxazin and could contribute to PPO-inhibitor resistance.

scholarly journals Control of Annual Bluegrass Weevil With Entomophagous Nematodes, 1994:

1996 ◽  
Vol 21 (1) ◽  
pp. 343-344
Author(s):  
Stanley R. Swier
Keyword(s):  
Organic Matter ◽  
Soil Moisture ◽  
Soil Organic Matter ◽  
Clay Soil ◽  
Golf Course ◽  
Efficacy Trial ◽  
Annual Bluegrass ◽  
Plot Size ◽  
Country Club ◽  
Large Plot

Abstract A large plot efficacy trial was conducted at Rutland Country Club, Rutland, VT on a golf course fairway. Plot size was 14 X 75 ft., arrayed in an RCB design, replicated 4 times. Treatments were applied 8 June at 0800 with an FMC hydraulic sprayer using 8004 nozzles delivering 3.6 gal. water/1000 ft2. Within 30 minutes of application, 0.2 inch irrigation water was applied to the plots. Plots were 60% annual bluegrass and 40% bentgrass. Larvae were predominantly third instar. Plots were rated at 7 and 14 DAT. Five cup cutter plugs were then taken per plot and analyzed in the lab. The number of live larvae were recorded. Conditions at the time of treatment were: air temperature 64.4°F; wind, 2 MPH; sky, clear; soil temperature, 1 inch –66°F; thatch depth, 0.25 inch soil pH, 5.2; slope, 3%; soil texture, loam: 48% sand, 42% silt, 10% clay; soil organic matter, 7.5%; soil moisture, 21.3%; post-treatment precipitation, 0.2 inch every other day.

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