Influence of Irrigation and Wetting Agent on Fungicide Residues in Creeping Bentgrass.

Fungicides (azoxystrobin, propiconazole, pyraclostrobin, and thiophanate-methyl) were applied to field plots of creeping bentgrass established on a sand-based root zone substrate and maintained at a cutting height of 0.34 cm. The wetting agent, a modified alkylated polyol, was applied 24 h prior to fungicide application. Irrigation (0.51 cm) was applied to plots immediately after the fungicide spray. Turf was sampled nine times over 42 days to examine fungicide residues in three components of the turf profile: verdure/thatch, roots, and soil. Residues were extracted from samples and then quantified using a liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) procedure. The experiment was run twice. Wetting agent had little or no effect on fungicide distribution in any of the turf components. Postapplication irrigation had little effect on residues observed in the verdure/thatch component. Significant irrigation treatment effects were observed in root and soil components, but results varied among fungicides and sampling dates. Where significant effects were observed for the irrigation plus wetting agent treatment, results generally mirrored outcomes for irrigation treatment.

Spatial and temporal distribution of fungicides applied to creeping bentgrass.

Turf managers often rely on fungicides to limit damage caused by root diseases. Because fungicides are applied to aboveground surfaces and do not move basipetally, they are effective against root pathogens only when fungitoxic concentrations migrate to the rhizosphere. This research focused on the distribution of modern fungicides in verdure, thatch, sand, and roots of creeping bentgrass [ L. var. (Huds.) Farw.] maintained as a putting green. The fungicides azoxystrobin (methyl (E)-2-[2-[6-(2-cyanophenoxy)pyrimidin-4-yloxy]phenyl]-3-methoxyacrylate), propiconazole (1,2,4-triazole, 1-((2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl)methyl), pyraclostrobin (carbamic acid, [2-[[[1-(4-chlorophenyl)-1H-pyrazol-3-yl]oxy]methyl]phenyl]methoxy-,methyl ester), and thiophanate-methyl (dimethyl 4,'4-o-phenylenebis[3-thioallophanate]) were applied to replicate field plots in a water volume of 815 L ha. Plots were sampled at 0, 3, 7, 10, 14, 17, and 21 d after application by extracting cores measuring 1.9 cm in diameter by 3.8 cm deep. Cores were separated into verdure/thatch, sand, and roots before quantitative determination (liquid chromatography, triple quadrupole mass spectrometry) of fungicide residues. Fungicide residues in verdure/thatch declined steadily with time and support previously reported results describing fungicide depletion. Fungicides were detected in roots and sand within 5 h of application at very low (1-15 mg kg) concentrations and remained at low levels throughout the sampling period. Fungicides differed with respect to amounts recovered per turfgrass component. Azoxystrobin and propiconazole were associated with roots for the duration of the experiment, but pyraclostrobin was nearly undetectable. Near-zero levels of all fungicides were detected in the sand component. Half-life values in the verdure/thatch component ranged from 2.3 to 18.9 d.

Residual Efficacy of Fungicides for Controlling Brown Patch on Creeping Bentgrass Fairways.

Residual efficacy of five fungicides (azoxystrobin, flutolanil, metconazole, polyoxin D, and pyraclostrobin) applied to creeping bentgrass (Agrostis stolonifera) maintained under golf course fairway conditions was determined using a bioassay method. During 2010 and 2011, six different field experiments were conducted. Each consisted of a single fungicide application followed by periodic (0, 3, 7, 10, 14, 17, and 21 days after application) turf sampling, inoculation of samples with an isolate of Rhizoctonia solani, and incubation in a controlled environment chamber for 48 h. For each sample date, fungicide efficacy was determined by measuring the extent of symptom expansion on fungicide treated and nontreated samples. Efficacy half-life values based on a two-parameter Weibull function were 3.1 to 14.0 days for the fungicides used in this study. Residual efficacy was further examined in 2011 by analyzing residues from creeping bentgrass verdure using liquid chromatography/time-of-flight mass spectrometry (LC/TOF-MS). Quantitative analysis from LC/TOF-MS revealed that fungicide residues were depleted rapidly following application to turfgrass and reinforced the precipitous decline in fungicide efficacy demonstrated by the bioassays. Regardless of fungicide, more than 90% of active ingredient applied was depleted from the verdure between 3 and 8 days after application, and more than 99% of fungicide was depleted at 17 days after application. This research provides a quantitative description of the temporal nature of loss of fungicide and fungicide protection from turf.

Reassessment of Fungicide Synergism for Control of Dollar Spot.

Experiments were designed to assess reports of synergism between propiconazole and other fungicides to control dollar spot in creeping bentgrass. In 2004 and 2006, two field experiments were conducted near Griffin, GA, and repeated near West Lafayette, IN. A third experiment was conducted at the Griffin site in 2007. In each experiment, replicated treatments of commercial formulations of propiconazole, triadimefon, iprodione, vinclozolin, and chlorothalonil were applied to plots of creeping bentgrass at the sublabel rates of 0.12, 0.38, 0.57, 0.38, and 2.29 kg a.i. ha-1, respectively. In addition, each of the latter four fungicides was tank mixed with propiconazole at the rates given, and applied as treatments. Plots were treated once in experiments 1 and 3, and three times at a 21-day interval in experiment 2. Nontreated plots served as controls. Disease intensity was assessed visually by estimating the area of each plot that exhibited dollar spot symptoms. Synergism between tank-mixed fungicides was determined by comparing actual and expected values of the duration of disease control (experiment 1) or the percentage of disease control (experiments 2 and 3) in treated plots. No synergistic interactions were detected at Griffin or West Lafayette in experiments 1 or 2. In the first trial of experiment 3, synergism was observed between propiconazole and iprodione on one of five ratings dates and between propiconazole and vinclozolin on two of five rating dates. However, no synergistic interactions were detected in the second trial. Results suggest that there is a low probability for turfgrass managers to take advantage of fungicide synergism to control dollar spot with the products and rates tested.

Residual Efficacy of Fungicides for Control of Dollar Spot on Creeping Bentgrass.

The duration of effective concentrations of fungicides for control of dollar spot on creeping bentgrass fairways was investigated using a bioassay technique. In each of three runs of the experiment, fungicide treatments were applied once to turf in replicated field plots; then, the plots were sampled periodically over 3 weeks by removing turf plugs from the field. The sampled plugs were placed in incubation containers and inoculated with sections from a 4-day-old colony of Sclerotinia homoeocarpa growing on potato dextrose agar. After a 96-h incubation period, the extent of pathogen growth on the turf plugs was measured. Results described a precipitous decline in effective concentration for all fungicide treatments beginning 7 to 10 days after application. The fungicides were only marginally effective at 14 days after application, and none provided any disease suppression at 21 days after application. The efficacy half-life (EHL) associated with four of the fungicides (chlorothalonil, iprodione, propiconazole, and thiophanate methyl) was estimated with two models. EHL estimates ranged from 6.1 to 15.2 days depending on the fungicide and the model. This research contributes to our knowledge of the duration of effective fungicide concentrations on creeping bentgrass and can provide insight for scheduling fungicide sprays for golf course fairways.

Winter Survival of the Perennial Ryegrass Pathogen Magnaporthe oryzae in North Central Indiana.

Winter survival of Magnaporthe oryzae in north central Indiana was investigated in response to reports and observations of sporadic disease incidence. Survival of the fungus in perennial ryegrass residue was assessed. Time course studies were designed to assess the conidia production potential of infested perennial ryegrass residue exposed to ambient and predetermined treatments. Approximately 50,000 conidia per gram dry weight were produced initially on infested residue. In all years of the study, ambient winter conditions in Lafayette, IN, reduced conidia production on residue to fewer than 60 conidia per gram by spring. Unless residue was dried prior to treatment, storage of residue at all temperatures tested reduced conidia production potential. Airborne M. oryzae conidia, over the plot of perennial ryegrass where the winter survival studies were conducted, were estimated from particles collected with a volumetric air sampler. The stand of perennial ryegrass was inoculated with residue infested with M. oryzae in the summer of 2000 and late fall of 2000 and 2001. The stand of ryegrass was not inoculated in the summers of 200l or 2002. Conidia were captured with the air sampler each year in early July, before outbreaks had been observed in north central Indiana, but capture peaked in September when outbreaks most often occur. Cumulative conidia capture followed disease severity in 2000; however, no disease was observed in 2001 or 2002. Results of this study suggest poor survival of M. oryzae, and inadequate populations of viable pathogen limit disease development in north central Indiana. Disease risk assessment in north central Indiana should include an estimate of viable inoculum.

Comparison of physical and performance characteristics of NCAA Division I football players: 1987 and 2000.

The purpose of this study was to compare normative data from present Division I National Collegiate Athletic Association football teams to those from 1987. Players were divided into 8 positions for comparisons: quarterbacks (QB), running backs (RB), receivers (WR), tight ends (TE), offensive linemen (OL), defensive linemen (DL), linebackers (LB), and defensive backs (DB). Comparisons included height, body mass, bench press and squat strength, vertical jump, vertical jump power, 40-yd-dash speed, and body composition. Independent t-tests were used to analyze the data with level of significance set at p < 0.01. Significant differences (p < 0.01) were found in 50 of 88 comparisons. From 1987 until 2000, Division I college football players in general have become bigger, stronger, faster, and more powerful. Further research is warranted to investigate if these trends will continue.

Comparison of selected physical fitness and performance variables between NCAA Division I and II football players.

The purpose of this study was to compare selected physical fitness and performance variables between National Collegiate Athletic Association (NCAA) Division I and II football players. The subjects included offensive and defensive starters, excluding kickers and punters from 26 NCAA Division I and 23 Division II teams. Offensive players were grouped and compared by the following positions: quarterback, running back, wide receiver, tight end, and line. Defensive players were grouped and compared by the following positions: line, linebackers, and backs. Division I players were better in 58 of 117 comparisons (p < or = 0.01). Division II players were not found to be better in any of the variables studied.

A Rapid PCR-Based Method for the Detection of Magnaporthe oryzae from Infected Perennial Ryegrass.

Gray leaf spot caused by Magnaporthe oryzae is a serious disease of perennial ryegrass in the midwestern United States. Symptoms of gray leaf spot can be confused with those caused by other fungal diseases that also are common during periods of high temperatures and ample moisture. Because turf managers must select appropriate fungicides for remedial treatment, accurate and timely identification of the pathogen is essential for efficient and effective disease management. We developed and evaluated a polymerase chain reaction (PCR)-based method to detect M. oryzae in infected perennial ryegrass tissue. The method utilizes a commercially available kit that is used for isolation and amplification of plant DNA from leaf tissue. The kit protocol was modified and found to be reliable for the extraction of M. oryzae DNA from infected perennial ryegrass. Primers were designed to amplify a 687-bp fragment of the Pot2 transposon that is found in multiple copies in the genome of the pathogen. The protocol amplified amounts of purified DNA as low as 5 pg and consistently and specifically detected M. oryzae in single diseased leaf blades as well as in field samples of infected perennial ryegrass. The total time required for detection was approximately 4 to 8 h.

A Survey of Physical Activity Levels of Certified Athletic Trainers.

OBJECTIVE: To determine the self-reported physical activities of certified athletic trainers (ATCs), both at work and at leisure. DESIGN AND SETTING: We used the Baecke Questionnaire of Habitual Physical Activity and also asked for demographic information, including employment setting, years of experience, education level, and position. SUBJECTS: The questionnaire was sent to 1200 randomly selected ATCs in the Mid-America Athletic Trainers' Association; the return rate was 53%. MEASUREMENTS: We used means, standard deviations, and ranges to describe the age, total fitness index, work, and leisure and sport indexes of men and women subjects. Independent t tests were used to compare the mean total activity index between men and women within this study and with previous studies. We examined differences in activity indexes by employment setting, position, and age with one-way analysis of variance and Fisher pairwise comparison tests. Two-way chi(2) analysis was used to determine the relationship between activity level and employment setting and position. Statistical significance was set at P =.05 for all analyses. RESULTS: Certified athletic trainers who work in a clinical setting had the highest mean total activity score at 9.1 points. Clinic ATCs scored significantly higher than high school ATCs and college ATCs. When compared by position, there were no significant differences among the mean total activity indexes; however, the mean work index of program directors was significantly lower than all other positions and the mean work index of high school and clinic ATCs was significantly higher than all other employment settings. CONCLUSIONS: Female ATCs scored significantly higher in total activity levels on the Baecke Questionnaire than their male counterparts. This is in contrast to the general population, investigated by other authors, in which men scored significantly higher than women on the same scale. Additionally, we compared the total activity levels by age, position, and employment setting. There was a significant difference by position only in the work index. The mean total index activity of the over-36-years-old group was significantly lower than all other age categories. There was no significant difference in mean total activity levels by employment setting.

Validation of a Commercial System for Remote Estimation of Wetness Duration.

To assess the accuracy of remote, real-time mathematical simulations of wetness duration and air temperature, hourly measurements of wetness duration and air temperature at 18 sites in the United States and Canada from May to September 1995 were compared with simulations for these sites provided by SkyBit, Inc. SkyBit simulations of mean, maximum, and minimum daily air temperatures varied from on-site measurements by less than 0.7°C but underestimated the duration of wet periods by an average of 3.4 h/day. At five of six stations tested, SkyBit underestimates of wetness duration were significantly (P < 0.01) larger on days when no rain was measured than on rainy days, indicating that simulations of dew-period duration were much less accurate than simulations of rain-period duration. The vast majority of hours SkyBit misclassified as dry occurred either when entire wet periods were missed (59.3%) or when the onset of a wet period was detected late (28.4%). The results suggest that revision of SkyBit wetness-simulation models should focus on reducing error rates during dew events. In simulations using two disease-warning models, TOM-CAST and Melcast, with mean values of measured and SkyBit-simulated wetness duration, SkyBit-simulated values resulted in fewer and later fungicide spray advisories than did measured values. The magnitude of these impacts varied with the magnitude of the simulation errors and with differences in the models' decision rules.