scholarly journals Smooth Crabgrass and Goosegrass Control with Metamifop in Creeping Bentgrass

2015 ◽  
Vol 25 (6) ◽  
pp. 757-761 ◽  
Author(s):  
Ethan T. Parker ◽  
J. Scott McElroy ◽  
Michael L. Flessner
Keyword(s):  
United States ◽  
Initial Treatment ◽  
Creeping Bentgrass ◽  
The United States ◽  
Field Trials ◽  
Agrostis Stolonifera ◽  
Single Application ◽  
Visible Injury ◽  
Eleusine Indica ◽  
Injury Potential

Smooth crabgrass (Digitaria ischaemum) and goosegrass (Eleusine indica) are problematic weeds in creeping bentgrass (Agrostis stolonifera) because of limited herbicide options for postemergence (POST) control and turfgrass injury potential. Metamifop is a herbicide currently being considered for release to markets in the United States but information is lacking on the most effective rates and application timings for smooth crabgrass and goosegrass control in creeping bentgrass. Field trials were conducted in Auburn, AL in 2009 and 2013 to evaluate metamifop rates (200 to 800 g·ha−1) and single or sequential application timings compared with fenoxaprop (51 to 200 g·ha−1) at two different mowing heights. Metamifop applied twice and three times sequentially at 200 g·ha−1 provided the greatest smooth crabgrass (>97%) and goosegrass (>90%) control at rough (1½ inch) and green (1/8 inch) mowing heights without unacceptable creeping bentgrass injury at 56 days after initial treatment. All treatments caused <20% visible injury on creeping bentgrass at both mowing heights except the highest rate of metamifop. Smooth crabgrass control at the green mowing height was greater than at the rough mowing height, especially at lower metamifop rates with a single application.

scholarly journals First Report of a Bacterial Disease on Creeping Bentgrass (Agrostis stolonifera) Caused by Acidovorax spp. in the United States

Plant Disease ◽  
2010 ◽  
Vol 94 (7) ◽  
pp. 922-922 ◽  
Author(s):  
P. R. Giordano ◽  
J. M. Vargas ◽  
A. R. Detweiler ◽  
N. M. Dykema ◽  
L. Yan
Keyword(s):  
United States ◽  
16S Rdna ◽  
Creeping Bentgrass ◽  
The United States ◽  
Agrostis Stolonifera ◽  
Bacterial Disease ◽  
16S Rdna Sequencing ◽  
First Report ◽  
Rdna Sequencing ◽  
Pure Cultures

In June of 2009, a golf course putting green sample of creeping bentgrass (Agrostis stolonifera L.) cv. Penn G-2 from a golf club in North Carolina was submitted to the Michigan State University Turfgrass Disease Diagnostic Laboratory for diagnosis. The sample exhibited symptoms of general wilt, decline, and characteristic necrosis from the leaf tips down. Fungal pathogens were ruled out when no phytopathogenic fungal structures were observed with microscopic examination of infected tissue. Symptoms appeared similar to those of annual bluegrass affected by bacterial wilt caused by Xanthomonas translucens pv. poae. Bacterial streaming was present in all of the cut infected tissue of the Penn G-2 bentgrass sample when observed with a microscope. To isolate the causal agent, cut leaf tissue (1- to 3-mm tips) exhibiting bacterial streaming was surface disinfected for 1 min in 10% sodium hypochlorite solution and rinsed for 1 min with sterile distilled water. Leaf blades were placed into Eppendorf microtubes with 20 μl of sterile phosphate-buffered saline (PBS) solution (pH 7) and macerated with a sterile scalpel. Serial dilutions up to 1 × 10–4 were performed in sterile PBS; 10 μl of each suspension was plated onto nutrient agar (NA) (Becton Dickinson, Sparks, MD) and incubated at room temperature for 5 days. Pure cultures of three commonly observed single bacterial colonies growing on plates from serial dilutions were made on NA medium. These pure cultures were grown for 5 days and used to inoculate three replicates of 5-week-old Penn G-2 plants that had uniformly filled in 8.5-cm-diameter pots grown under greenhouse conditions. Uninfected Penn G-2 creeping bentgrass plants were inoculated with 1 ml of 1.3 × 109 CFU/ml of bacterial suspension by adding drops of the suspension to blades of sterile scissors used to cut the healthy plants. Of the three different bacterial cultures selected to inoculate healthy plants, only one resulted in slight browning of leaf tips just 2 days after inoculation. The symptoms progressed, and by 5 days after inoculation, browning, twisting and leaf dieback to the sheath were observed. When leaf tips of the inoculated plants were cut, bacterial streaming was observed. Isolation of the bacterium from inoculated Penn G-2 plants was performed to fulfill Koch's postulates. Once isolated, a single bacterial colony was identified by 16S rDNA sequencing (Microcheck Inc. Northfield, VT). 16S rDNA sequencing results indicated that the causal agent of bacterial infection was a member of the Acidovorax genus, with a 100% sequence match to Acidovorax avenae subsp. avenae (2). The same nonflorescent, aerobic, gram-negative bacterium has been consistently isolated from inoculated plants exhibiting symptoms thus far. A member of the Acidovorax genus has also been identified as a pathogen of creeping bentgrass in Japan (1). To our knowledge, this is the first report of a bacterial disease affecting creeping bentgrass caused by Acidovorax spp. in the United States. References: (1) N. Furuya et al. J. Fac. Agric. Kyushu Univ. 54:13. 2009. (2) N. Schaad et al. Syst. Appl. Microbiol. 31:434. 2008.

scholarly journals Identification, Characterization, and Distribution of Acidovorax avenae subsp. avenae Associated with Creeping Bentgrass Etiolation and Decline

Plant Disease ◽  
2012 ◽  
Vol 96 (12) ◽  
pp. 1736-1742 ◽  
Author(s):  
Paul R. Giordano ◽  
Arielle M. Chaves ◽  
Nathaniel A. Mitkowski ◽  
Joseph M. Vargas
Keyword(s):  
United States ◽  
Creeping Bentgrass ◽  
The United States ◽  
Agrostis Stolonifera ◽  
Golf Courses ◽  
Putting Greens ◽  
16S Rdna Sequence ◽  
16S Rdna Sequence Analysis ◽  
First Occurrence ◽  
Significant Disease

Bacterial etiolation and decline caused by Acidovorax avenae subsp. avenae is an emerging disease of creeping bentgrass (Agrostis stolonifera) in and around the transition zone, a unique area of turfgrass culture between cool and warm regions of the United States. It is suspected that the disease has been present for many years, although diagnosis of the first occurrence was not reported until 2010. Solicitation of samples from golf courses in 2010 and 2011 was undertaken to investigate the prevalence and dissemination of Acidovorax avenae subsp. avenae on creeping bentgrass. At least 21 isolates from 13 states associated with these outbreaks on golf courses were confirmed as A. avenae subsp. avenae by pathogenicity assays and 16S rDNA sequence analysis at two independent locations. Pathogenicity testing of bacterial isolates from creeping bentgrass samples exhibiting heavy bacterial streaming confirmed A. avenae subsp. avenae as the only bacterium to cause significant disease symptoms and turfgrass decline. Host range inoculations revealed isolates of A. avenae subsp. avenae to be pathogenic on all Agrostis stolonifera cultivars tested, with slight but significant differences in disease severity on particular cultivars. Other turfgrass hosts tested were only mildly susceptible to Acidovorax avenae subsp. avenae infection. This study initiated research on A. avenae subsp. avenae pathogenicity causing a previously uncharacterized disease of creeping bentgrass putting greens in the United States.

Fungicide efficacy on tar spot and yield of corn in the Midwestern United States

2022 ◽  
Author(s):  
Darcy E. P. Telenko ◽  
Martin I. Chilvers ◽  
Adam Byrne ◽  
Jill Check ◽  
Camila Rocco Da Silva ◽  
...  
Keyword(s):  
United States ◽  
Growth Stage ◽  
Field Trials ◽  
Corn Belt ◽  
Yield Losses ◽  
Single Application ◽  
Midwestern United States ◽  
Tar Spot ◽  
Significant Yield ◽  
Foliar Fungicide

Tar spot of corn caused by Phyllachora maydis has recently led to significant yield losses in the eastern corn belt of the Midwestern United States. Foliar fungicides containing quinone outside inhibitors(QoI), demethylation inhibitors(DMI), and succinate dehydrogenase inhibitors(SDHI) are commonly used to manage foliar diseases in corn. To mitigate the losses from tar spot thirteen foliar fungicides containing single or multiple modes of action (MOA/FRAC groups) were applied at their recommended rates in a single application at the standard tassel/silk growth stage timing to evaluate their efficacy against tar spot in a total of eight field trials in Illinois, Indiana, Michigan, and Wisconsin during 2019 and 2020. The single MOA fungicides included either a QoI or DMI. The dual MOA fungicides included a DMI with either a QoI or SDHI, and fungicides containing three MOAs included a QoI, DMI, and SDHI. Tar spot severity estimated as the percentage of leaf area covered by P. maydis stroma of the non-treated control at dent growth stage ranged from 1.6 to 23.3% on the ear leaf. Averaged across eight field trials all foliar fungicide treatments reduced tar spot severity, but only prothioconazole+trifloxystrobin, mefentrifluconazole+pyraclostrobin+fluxapyroxad, and mefentrifluconazole+pyraclostrobin significantly increased yield over the non-treated control. When comparing fungicide treatments by the number of MOAs foliar fungicide products that had two or three MOAs decreased tar spot severity over not treating and products with one MOA. The fungicide group that contained all three MOAs significantly increased yield over not treating with a fungicide or using a single MOA.

WELCOMING REMARKS

PEDIATRICS ◽  
1969 ◽  
Vol 44 (5) ◽  
pp. 791-792
Author(s):  
Merritt Low
Keyword(s):  
United States ◽  
American Academy ◽  
One Health ◽  
The United States ◽  
Field Trials ◽  
Accident Prevention ◽  
American Academy Of Pediatrics ◽  
Job Safety ◽  
Developing Area ◽  
Made In

The American Academy of Pediatrics has long been interested in the control of Childhood Injuries; its first formal committee was the Committee on Accident Prevention. The pediatrician is a primary accident preventer and should indeed have a big stake and commitment here. He is basically a "consumer," yet he must be convinced of the product he uses and in turn passes on. Though he has the humility of an amateur, he is allied with the expert and begs for his help. He sees the great strides made by industry, even in the newly developing area of "off-the-job" safety, and the advances made in the therapeutic but not the prophylactic responsibilities of accident prevention as he surveys the situation. Yet, is he truly convinced? If so, he could do more. We exhort ourselves to immunize our children with a safety vaccine, but is this just borrowed jargon? What are the ingredients of the vaccine? Are they dead or alive? Where are the field trials? Where are the proving figures of effectiveness? A hard look shows us that this number one health problem is not being solved. (I scarcely need remind this group of the statistics and facts: 15,000 children under 15, including 5,000 pre-school children, die of accidents in the United States each year; 15 million children go to doctors for care of accidents in a year; all accidents cost the country over 15 billion dollars a year). In our primary reliance on the tool of "education," we fall victims to the fact-of-life fallacy-if we provide facts we automatically get results.

DSM-5 Field Trials in the United States and Canada, Part II: Test-Retest Reliability of Selected Categorical Diagnoses

2013 ◽  
Vol 170 (1) ◽  
pp. 59-70 ◽  
Author(s):  
Darrel A. Regier ◽  
William E. Narrow ◽  
Diana E. Clarke ◽  
Helena C. Kraemer ◽  
S. Janet Kuramoto ◽  
...  
Keyword(s):  
United States ◽  
The United States ◽  
Field Trials ◽  
Retest Reliability ◽  
Dsm 5 ◽  
Test Retest Reliability

scholarly journals Genetic Diversity of Sclerotinia homoeocarpa Isolates from Turfgrasses from Various Regions in North America

Plant Disease ◽  
2004 ◽  
Vol 88 (11) ◽  
pp. 1269-1276 ◽  
Author(s):  
G. Viji ◽  
W. Uddin ◽  
N. R. O'Neill ◽  
S. Mischke ◽  
J. A. Saunders
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Creeping Bentgrass ◽  
The United States ◽  
Vegetative Compatibility ◽  
Major Group ◽  
Golf Courses ◽  
Sclerotinia Homoeocarpa ◽  
Dollar Spot ◽  
Geographical Regions

Sixty-seven isolates of Sclerotinia homoeocarpa, causing dollar spot disease in creeping bentgrass, annual bluegrass, Bermudagrass, and perennial ryegrass turf, collected from 23 golf courses in various geographical regions of the United States and Canada between 1972 and 2001, were characterized by vegetative compatibility, genetic diversity, and pathogenicity. Eleven vegetative compatibility groups (VCGs A to K) were identified among the isolates tested in this study, and five of them (VCGs G to K) were new. VCG B was the most predominant group, typifying 33 isolates (51%) tested. S. homoeocarpa isolates collected from golf courses in Pennsylvania belonged to seven VCGs (A, B, E, F, G, I, and K), whereas three groups were observed in those collected from New York (B, E, and G) and New Jersey (E, H, and I). Two isolates, one each from Pennsylvania and Canada, were incompatible when paired with the tester isolates in all possible combinations, and did not fall into any known VCG. An isolate collected from Canada was compatible with tester isolates from two VCGs (C and D). Genetic analyses using amplified fragment length polymorphism (AFLP) showed the presence of two genetically distinct groups, designated as major group and the minor group. The major group included 36 isolates collected from various golf courses in the United States and Canada. Two isolates collected from bermudagrass in Florida formed a separate cluster, the minor group. Isolates that belonged to the major group were further divided into two subgroups (1 and 2). Subgroup 1 consisted of all the isolates that belonged to VCGs A, E, G, H, and I. Three of the four isolates that belonged to VCG K also were clustered with isolates of subgroup 1. Subgroup 2 consisted of all the isolates from VCG B, and one each from VCGs F and K. Pathogenicity assays on Penncross creeping bentgrass showed significant differences (P = 0.05) in virulence among the isolates. Overall, a relationship between virulence and VCGs was observed, in which certain virulence groups corresponded to specific VCGs; however, such a relationship was not observed between virulence and AFLPs. Close similarity among isolates of S. homoeocarpa collected from different locations in the United States and Canada suggests that isolates of the same genotype could be involved in outbreaks of dollar spot epidemics at multiple locations.

Corroboration That Highly Resistant Impatiens Cultivars Are Not Immune to Downy Mildew Disease: A Report of Crop Losses from Two California Producers

2020 ◽  
Vol 21 (3) ◽  
pp. 214-216
Author(s):  
Margery Daughtrey ◽  
Janna Beckerman ◽  
William J. Davis ◽  
Karen Rane ◽  
Jo Anne Crouch
Keyword(s):  
United States ◽  
Downy Mildew ◽  
Genetic Resistance ◽  
Disease Outbreaks ◽  
The United States ◽  
Field Trials ◽  
Commercial Production ◽  
Impatiens Walleriana ◽  
Action Groups ◽  
Downy Mildew Disease

Two new series of Impatiens walleriana (impatiens) cultivars, Beacon and Imara XDR, were released to commercial growers in the United States in 2019 to 2020. Field trials show these new cultivar series are highly resistant to impatiens downy mildew (IDM). However, neither of these two impatiens series are completely immune to the disease, and preventive fungicide programs are still recommended for use throughout production to maintain plant health. Here we report two destructive outbreaks of IDM from Imara XDR in two commercial production facilities in California, one in 2019 and one in 2020. The disease outbreaks were caused by a known rDNA genotype of Plasmopara destructor (synonym = P. obducens). Modified Koch’s postulates showed that the pathogen could infect and cause disease in both Beacon and Imara XDR plants. Mefenoxam applied by both growers may have been ineffective due to resistance in P. destructor populations, which has been demonstrated on several previous occasions. Given these findings, fungicide programs intended to supplement genetic resistance should not be overly reliant upon application of mefenoxam and should utilize effective materials from different mode of action groups, in rotation. Fungicides to supplement genetic resistance are particularly appropriate in frost-free areas or in any circumstances that provide a potential inoculum source.

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