scholarly journals Yield Losses Due to Crown Rust in Winter Oats in Alabama

2016 ◽  
Vol 17 (2) ◽  
pp. 95-100 ◽  
Author(s):  
K. L. Bowen ◽  
A. K. Hagan ◽  
M. Pegues ◽  
J. Jones
Keyword(s):  
Flag Leaf ◽  
Relative Yield ◽  
Field Studies ◽  
Crown Rust ◽  
Common Disease ◽  
Yield Losses ◽  
Application Timing ◽  
Fungicide Application ◽  
Head Extension ◽  
Better Than

Crown rust is a common disease on winter oats in Alabama. While considered the most destructive disease of oats, little has been done in recent years, with current cultivars, to demonstrate yield losses due to crown rust. Field studies were conducted to determine the effect of fungicides and application timing on crown rust severity and yield. All fungicides reduced crown rust and improved yield. Two fungicide applications were better than a single fungicide application for reducing crown rust. Relative to yield, a single fungicide application during flag leaf development (FS 8-9) was better than a single application during head extension (FS 10.3). When compared with the non-treated control, significant yield gains were obtained with Tilt and Headline in all four years and Stratego YLD in three of four years. Fungicide programs resulted in a broad range of crown rust severities; disease levels were highly related to decreases in yield in each of four years. In two study years, ‘Coker 227’ was more damaged by crown rust, with about 10% yield loss for each unit disease, than was ‘Horizon 270,’ with 2.5 to 4.5% loss. However, in 2013, virulence patterns of the crown rust pathogen shifted and disease on Horizon 270 was greater than that on Coker 227; relative yield losses were also much lower in 2013. Accepted for publication 15 April 2016. Published 4 May 2016.

scholarly journals Effect of Foliar Fungicides on Late-season Anthracnose Stem Blight on Soybean

2014 ◽  
Vol 15 (3) ◽  
pp. 118-121 ◽  
Author(s):  
Nathan R. C. Bestor ◽  
Alison E. Robertson ◽  
Daren S. Mueller
Keyword(s):  
Yield Components ◽  
Field Studies ◽  
Specific Yield ◽  
Colletotrichum Truncatum ◽  
Symptom Development ◽  
Yield Losses ◽  
Application Timing ◽  
Late Season ◽  
Fungicide Application ◽  
Stem Blight

Anthracnose stem blight, caused by Colletotrichum truncatum, is responsible for soybean (Glycine max) yield losses in subtropical and tropical growing regions. There are inadequate data regarding the effect of anthracnose stem blight on yield in Iowa, and it is unknown if fungicide application can manage this disease. Field studies were conducted from 2008 to 2010 to determine the effect of fungicide application timing on late-season development of this disease. We also investigated the effect of anthracnose stem blight on yield and specific yield components. Fungicides reduced late-season symptom development when compared to the untreated control; however, there were no differences in yield and yield components. While foliar fungicides can reduce late-season disease development, anthracnose stem blight typically should not affect crop management decisions involving use of foliar fungicides on soybean in Iowa. Accepted 7 July 2014. Publication 14 August 2014.

Response of Rice (Oryza sativa) to Low Rates of Glyphosate and Glufosinate

2011 ◽  
Vol 25 (2) ◽  
pp. 198-203 ◽  
Author(s):  
Brad Davis ◽  
Robert C. Scott ◽  
Jason K. Norsworthy ◽  
Edward Gbur
Keyword(s):  
Yield Loss ◽  
Flag Leaf ◽  
Field Studies ◽  
Leaf Length ◽  
University Of Arkansas ◽  
Yield Losses ◽  
Time Of Application ◽  
Flag Leaf Length ◽  
The University ◽  
Significant Injury

Field studies were conducted in 2007 and 2008 at the University of Arkansas at Pine Bluff farm near Lonoke to evaluate and compare the effects of low rates of glufosinate and glyphosate on rice. Two rice cultivars were seeded, and glyphosate and glufosinate were applied at 1/2, 1/4, and 1/8 of the labeled use rate of 870 g ae ha−1and 616 g ai ha−1, respectively, at the three- to four-leaf, panicle initiation (PI), and boot stages. Rice canopy height reductions, reduction in flag leaf length, prolonged maturity, and yield losses were caused by both herbicides at all evaluated application timings. Although both herbicides caused significant injury, symptoms varied greatly between the two herbicides. Glufosinate injury to rice was more rapid and visually intense than with glyphosate. Glufosinate symptoms, which consisted of rapid necrosis, were visible in 1 to 2 d, whereas glyphosate symptoms, stunting and chlorosis, became visible after 7 to 10 d or not at all depending on time of application. Glyphosate applied at the 1/2× rate to rice in the boot growth stage caused less than 10% injury at 3 wk after treatment but resulted in 80% yield loss. Glufosinate at boot caused 80% injury and 80% yield loss. Glyphosate symptoms from PI and boot timings were typically only visible at heading and included malformed panicles and shortened flag leaves. Harvested grain seed weights were reduced as much as 14% by either herbicide applied at PI and boot. Germination of harvested grain was not affected by any treatment. At the rates evaluated in this research, glufosinate-induced injury to rice can be just as detrimental as glyphosate in reducing yield.

scholarly journals Timing of Strobilurin Fungicide for Control of Top Dieback in Corn

2017 ◽  
Vol 18 (2) ◽  
pp. 129-135 ◽  
Author(s):  
Eric Adee ◽  
Stewart Duncan
Keyword(s):  
Zea Mays L ◽  
Field Studies ◽  
The Other ◽  
Colletotrichum Graminicola ◽  
Yield Losses ◽  
Fungicide Application ◽  
Dent Corn ◽  
Untreated Check ◽  
Strobilurin Fungicide ◽  
Significant Yield

Significant yield losses can result from top dieback (TDB) in dent corn (Zea mays L.), which is caused by infection by the fungus Colletotrichum graminicola, which also causes anthracnose. Research on the effectiveness of fungicide application is limited because of the unpredictable nature of the disease. Three field studies were established to assess the timing of fungicide application for foliar diseases that developed TDB, one in Illinois (2010) and the other two in Kansas (2015 and 2016). Fungicide applications at tasseling and later were effective in reducing the incidence of TDB by over 20% and increasing yield over 900 kg/ha, or over 7%, while earlier applications (V5 to V8) did not reduce TDB nor increase yield compared with the untreated check.

Glufosinate Application Timing and Rate Affect Peanut Yield

2013 ◽  
Vol 40 (2) ◽  
pp. 115-119 ◽  
Author(s):  
Eric P. Prostko ◽  
Theodore M. Webster ◽  
Michael W. Marshall ◽  
Ramon G. Leon ◽  
Timothy L. Grey ◽  
...  
Keyword(s):  
Significant Interaction ◽  
Response Curve ◽  
Field Studies ◽  
Yield Losses ◽  
Application Time ◽  
Target Movement ◽  
Potential Yield ◽  
Yield Data ◽  
Application Timing ◽  
The Us

ABSTRACT Field studies were conducted at 13 locations across the US peanut belt during 2010–2012 to evaluate peanut response to postemergence applications of glufosinate. Glufosinate was applied at 0, 41, 82, 164, 328 and 656 g ai/ha 30, 60, and 90 days after planting (DAP). There was a significant interaction for peanut yield between application time and glufosinate rate; peanut yield data were regressed on rate of glufosinate and fit to a log-logistic dose response curve by application timing. At 30 DAP, peanut yield ranged from 16 to 92% of the non-treated control, with glufosinate at 266 g/ha causing an estimated 50% reduction in yield (Y50). At 60 DAP, peanut yield ranged from 16 to 82% of the nontreated control, with Y50  =  266 g/ha of glufosinate. Peanut yield when glufosinate was applied at 90 DAP ranged from 20 to 78% of the non-treated control; Y50  =  187 g/ha of glufosinate, which was lower than that at 30 DAP and indicated greater peanut sensitivity. Peanut plants treated at 30 DAP had more time to recover from glufosinate injury at the lower rates and/or were in a less susceptible stage of growth relative to 90 DAP. These data provide peanut growers across the US with an estimate of potential yield losses associated with mis-application, off-target movement, or sprayer contamination of glufosinate.

Characterization of carinata tolerance to select herbicides using field dose-response studies

2021 ◽  
pp. 1-26
Author(s):  
Sandra R. Ethridge ◽  
Angela Post ◽  
Pratap Devkota ◽  
Michael J. Mulvaney ◽  
Ramon G. Leon
Keyword(s):  
Population Density ◽  
Dose Response ◽  
Field Experiments ◽  
Relative Yield ◽  
Field Studies ◽  
Yield Losses ◽  
Control Volunteer ◽  
Postemergence Herbicides ◽  
Response Field

Abstract Field experiments were conducted from 2017 to 2019 to determine the tolerance of carinata to several preemergence and postemergence herbicides. Preliminary screenings identified herbicides which caused large variation on carinata injury, indicating the potential for selectivity. Dose-response field studies were conducted to quantify the tolerance of carinata to select herbicides. Diuron applied preemergence at rates of 280 g ai ha−1 or above reduced carinata population density 54% to 84% compared to the nontreated control. In certain locations, clomazone applied preemergence caused minor injury with an acceptable level of carinata tolerance and only doses above 105 g ai ha−1 caused yield reductions. Napropamide doses of 2,856 g ai ha−1 or higher applied preemergence caused at least 25% injury to carinata; however, the damage was not severe enough to reduce yields. Simazine applied postemergence at rates above 1,594 g ai ha−1 caused 50% or more injury, resulting in yield losses ranging from 0 to 95% depending on location. Clopyralid applied postemergence at 2,512 g ai ha−1 caused 25% injury with relative yield reductions which varied across locations. The present study identified clomazone and napropamide applied preemergence, and clopyralid applied postemergence as potential herbicides for weed control in carinata. In contrast, diuron, simazine, metribuzin, imazethapyr, and chlorimuron caused high levels of carinata mortality and can be used to control volunteer carinata plants in rotational crops.

scholarly journals Epidemics and Yield Losses due to Corynespora cassiicola on Cotton

Plant Disease ◽  
2018 ◽  
Vol 102 (12) ◽  
pp. 2494-2499 ◽  
Author(s):  
Kira L. Bowen ◽  
Austin K. Hagan ◽  
Malcolm Pegues ◽  
Jarrod Jones ◽  
H. Brad Miller
Keyword(s):  
Disease Onset ◽  
Yield Response ◽  
Corynespora Cassiicola ◽  
Yield Losses ◽  
Fungicide Application ◽  
Target Spot ◽  
Significant Yield ◽  
Epidemic Development ◽  
Gompertz Growth Model ◽  
Better Than

Target spot, caused by Corynespora cassiicola, has recently emerged as a problematic foliar disease of cotton. This pathogen causes premature defoliation during boll set and maturation that can subsequently impact yield, and on certain cotton cultivars loss can be substantial. This study sought to better understand target spot epidemics and disease-incited yield losses on cotton. In order to establish a range of disease, varying numbers of fungicide applications were made to each of two cotton cultivars in each of four site-years. Target spot intensity was rated over several dates beginning in late July or early August and continuing into September. Yield of seed plus lint (seed cotton) was recorded at harvest. When analyzed across cultivars, a second or third fungicide application increased yield compared with no treatment. Lack of significant yield response with a single fungicide application may have been due to timing of that application which preceded disease onset. The cultivar PhytoGen 499 WRF had consistently greater defoliation than any of the three Deltapine cultivars grown in each site-year. However, yields of both cultivars responded similarly to the fungicide regimes. Yield loss models based on late August defoliation were only predictive at site-years where conditions favored target spot development, i.e., abundant rain and moderate temperatures. Epidemic development fit the Gompertz growth model better than it did a logistic model. Knowledge of the underlying mathematical character of the epidemiology of target spot will prove useful for development of a predictive model for the disease.

Quackgrass control in established alfalfa with sethoxydim

1994 ◽  
Vol 74 (3) ◽  
pp. 647-651 ◽  
Author(s):  
E. K. Twidwell ◽  
K. D. Kephart ◽  
S. A. Clay
Keyword(s):  
Crude Protein ◽  
Dry Matter ◽  
Stand Density ◽  
Field Studies ◽  
Forage Yield ◽  
Application Timing ◽  
Elytrigia Repens ◽  
Repeated Applications ◽  
Medicago Sativa L ◽  
Better Than

Field studies were conducted during 1990 and 1991 in northeast South Dakota to determine the effect of sethoxydim application timing on quackgrass [Elytrigia repens (L.) Nevski] control in established alfalfa (Medicago sativa L.). Sethoxydim was applied as single applications in the fall, spring, after the second cut of alfalfa or as various repeated applications in the fall, spring, and after the first and second cuts of alfalfa. The alfalfa-quackgrass mixture was harvested three times per year, and dry matter yields of alfalfa, quackgrass, and total herbage were determined. Total herbage samples were analyzed for crude protein (CP) concentration. Usually, single application of sethoxydim in either the fall or spring did not control quackgrass as well as multiple applications. However, three and four applications of sethoxydim per year did not consistently control quackgrass any better than two applications per year. Sethoxydim reduced quackgrass yields in most instances, but yields and CP concentrations of total herbage were seldom affected. Use of sethoxydim for quackgrass control in established alfalfa may be warranted only in situations where relatively weed-free forage is desired. Key words: Application timing, forage yield, competition, stand density

Are fungicide applications to control crown rust of oat beneficial?

2014 ◽  
Vol 94 (5) ◽  
pp. 911-922 ◽  
Author(s):  
W. E. May ◽  
N. Ames ◽  
R. B. Irvine ◽  
H. R. Kutcher ◽  
G. P. Lafond ◽  
...  
Keyword(s):  
Seed Quality ◽  
Genetic Resistance ◽  
Crown Rust ◽  
Test Weight ◽  
Yield Losses ◽  
Fungicide Application ◽  
Yield And Quality ◽  
Seeding Date ◽  
Primary Means ◽  
Rust Severity

May, W. E., Ames, N., Irvine, R. B., Kutcher, H. R., Lafond, G. P. and Shirtliffe, S. J. 2014. Are fungicide applications to control crown rust of oat beneficial? Can. J. Plant Sci. 94: 911–922. Crown rust (Puccinia coronata Corda f. sp. avenae Eriks.) negatively impacts seed quality and yield in oat (Avena sativa L.) in rust-prone areas of eastern Saskatchewan, Manitoba, Ontario, and Quebec. Genetic resistance is the primary means for controlling this disease, but early seeding and fungicide applications have been suggested to reduce yield losses. Trials were conducted in six locations in Saskatchewan and Manitoba in 2009–2011 to determine the interactions between cultivar, fungicide application, crown rust and seeding date. The cultivars were chosen to represent a range of resistance to the current races of crown rust: AC Morgan, very susceptible; CDC Orrin, susceptible; CDC Boyer, partially resistant; and Leggett, resistant. Crown rust severity varied among locations and cultivars. The sprayed flag and penultimate leaves of AC Morgan tended to have similar amounts of crown rust as the unsprayed leaves of CDC Boyer and CDC Orrin regardless of the level of crown rust infection. Leggett's yield and quality did not respond to fungicide application. Only AC Morgan consistently benefited from a fungicide application. At high crown rust sites fungicide application improved AC Morgan's yield by 17 to 27% (690 kg ha−1 to 781 kg ha−1). Delayed seeding reduced grain yield from 8 to 26% with 8% occurring at low crown rust sites and the largest reductions occurring at high crown rust sites in susceptible cultivars. The test weight of AC Morgan increased from 242 g 0.5 L−1 to 255 g 0.5 L−1 when fungicide was applied at high crown rust sites seeded in mid-May. Fungicide application did not change the test weight of Leggett. The β-glucan level was affected more by seeding date (0.4%) and cultivar (0.4%) than fungicide application (0.1%). Seeding a cultivar with better crown rust resistance than AC Morgan in mid-May eliminated most of the benefits derived from fungicide application. These results indicate that prophylactic fungicide applications are unlikely to provide yield improvement when early planting is combined with even a moderately disease-resistant cultivar.

Influence of Growth Stage on Rice (Oryza sativa) Tolerance to Triclopyr

1992 ◽  
Vol 6 (4) ◽  
pp. 930-933 ◽  
Author(s):  
Joe E. Street ◽  
John L. Baldwin ◽  
Thomas C. Mueller
Keyword(s):  
Seed Weight ◽  
Growth Stage ◽  
Flag Leaf ◽  
Field Studies ◽  
Rice Cultivar ◽  
Yield Reduction ◽  
Application Timing ◽  
Booting Stage ◽  
Dwarf Cultivar ◽  
Milling Yield

Field studies were conducted from 1985 to 1989 on a Sharkey clay to examine injury to a semi-dwarf rice cultivar, ‘Lemont’, from triclopyr or triclopyr plus propanil. Triclopyr applied in the booting stage reduced yield two of three years, with the observed yield reduction possibly caused by epinasty of the rice flag leaf. Triclopyr application to three- to four-leaf rice caused hyponasty. Triclopyr did not reduce plant height, seed weight, germination, or total milling yield. Triclopyr plus propanil caused more leaf burn that triclopyr alone, but yields were not reduced compared with the untreated control. This research indicated that triclopyr and triclopyr plus propanil can be used in rice production with the semi-dwarf cultivar, Lemont, with the potential to minimize drift to non-target crops due to the greater flexibility in application timing compared with 2,4-D application.

scholarly journals Evaluation of Weather-Based Spray Advisories for Improved Control of Peanut Stem Rot

Plant Disease ◽  
2008 ◽  
Vol 92 (3) ◽  
pp. 392-400 ◽  
Author(s):  
S. L. Rideout ◽  
T. B. Brenneman ◽  
A. K. Culbreath ◽  
D. B. Langston
Keyword(s):  
Disease Management ◽  
Soil Temperature ◽  
Environmental Conditions ◽  
Sclerotium Rolfsii ◽  
Stem Rot ◽  
Application Timing ◽  
Foliar Diseases ◽  
Fungicide Application ◽  
Temperature And Precipitation ◽  
Better Than

Stem rot of peanut, caused by the soilborne fungus Sclerotium rolfsii, is greatly influenced by environmental conditions. Disease management programs rely heavily on fungicides, which are applied on a calendar-based program. To determine whether improved control of stem rot could result from weather-based spray advisories, models were constructed using what is currently known about the biology of S. rolfsii and etiology of stem rot epidemics in peanut. Spray advisories based on soil temperature, precipitation, and host parameters were tested, along with advisories focusing on soil temperature and precipitation or precipitation alone. The advisories were evaluated and compared with the currently used calendar-based program over four locations annually for 3 years. Fungicide application timing had a significant effect on both stem rot control and resulting pod yields. In general, stem rot control following the advisories considering soil temperature, precipitation, and canopy growth was similar or better than that offered by the calendar-based program, but yields generally were comparable. The AU-Pnut advisory for foliar diseases also was effective for scheduling azoxystrobin applications for stem rot.

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