Implications of fungicide application timing and post-spray irrigation on disease control and peanut yield

2011 ◽  
Vol 38 (1) ◽  
pp. 48-56 ◽  
Author(s):  
J. Augusto ◽  
T. B. Brenneman
Keyword(s):  
Disease Control ◽  
Leaf Spot ◽  
Stem Rot ◽  
Systemic Fungicide ◽  
Cercospora Arachidicola ◽  
Application Timing ◽  
Fungicide Application ◽  
Positive Effects ◽  
Spray Irrigation ◽  
Night And Day

Abstract Applying fungicides at night when the leaves are folded and using irrigation water after application have both been shown to increase deposition of fungicides in the lower plant canopy, improve control of stem rot (caused by Sclerotium rolfsii), and increase peanut (Arachis hypogaea) yield. To evaluate the interactive effects of these two practices, four applications of a protectant fungicide, chlorothalonil (1.26 kg a.i./ha), or a systemic, prothioconazole + tebuconazole (0.23 kg a.i./ha), tebuconazole (0.21 kg a.i./ha), flutolanil + propiconazole (0.45 kg a.i./ha), pyraclostrobin (0.21 kg a.i./ha), or two applications of a systemic, fluoxastrobin (0.17 kg a.i./ha) or azoxystrobin (0.31 kg a.i./ha) were sprayed either at night (3 a.m. to 5 a.m., when peanut leaves were folded) or during daylight (10 a.m. to 12 p.m., when peanut leaves were unfolded). Fungicides were applied as sub-subplots and night and day fungicide application timings as subplots in a split-split plot design with post-spray irrigation and nonpost-spray irrigation as whole plots to evaluate disease control and peanut yield in 2008 and 2009. In 2008, leaf spot intensity (early leaf spot caused by Cercospora arachidicola) was low and disease control was similar regardless of application timing or fungicide across post-spray irrigation treatments. In 2009, leaf spot was severe and disease control for night and day applications of a systemic fungicide was similar across post-spray irrigation, but pyraclostrobin and prothioconazole + tebuconazole had the lowest ratings. Interaction of fungicide, application timing and post-spray irrigation was significant for stem rot and yield. Night application of prothioconazole + tebuconazole, flutolanil + propiconazole or pyraclostrobin showed the most increase in stem rot control and yield compared with day application among the evaluated fungicides, but the positive effects on stem rot control and yield were minimal with post-spray irrigation. The effects of application timing and post-spray irrigation on fungicide efficacy were not the same for all fungicides.

Use of Azoxystrobin for Disease Control in Texas Peanut

2000 ◽  
Vol 27 (2) ◽  
pp. 83-87 ◽  
Author(s):  
W. J. Grichar ◽  
B. A. Besler ◽  
A. J. Jaks
Keyword(s):  
Disease Control ◽  
Rhizoctonia Solani ◽  
Leaf Spot ◽  
Sclerotium Rolfsii ◽  
Field Studies ◽  
South Texas ◽  
Stem Rot ◽  
Cercospora Arachidicola ◽  
Late Leaf Spot ◽  
Untreated Check

Abstract Field studies were conducted at 11 locations across south Texas from 1994 to 1997 to determine the activity of azoxystrobin against southern stem rot (Sclerotium rolfsii Sacc.), Rhizoctonia pod rot (Rhizoctonia solani Kuhn), early leaf spot (Cercospora arachidicola Hori) and late leaf spot [Cercosporidium personatum (Berk. & Curt.) Deighton]. Azoxystrobin at 0.22 to 0.45 kg/ha applied twice provided control of stem rot, Rhizoctonia pod rot, and leaf spot comparable to tebuconazole at 0.2 kg/ha applied four times. Peanut yield increases were evident with all fungicide treatments over the untreated check.

2012–2016 On-Farm Evaluation of Fungicide Programs for Peanut Disease Control in Hamilton County, Florida

EDIS ◽  
2017 ◽  
Vol 2017 (4) ◽  
Author(s):  
Keith W. Wynn ◽  
Nicholas S. Dufault ◽  
Rebecca L. Barocco
Keyword(s):  
Plant Pathology ◽  
Disease Control ◽  
Leaf Spot ◽  
Fungal Disease ◽  
White Mold ◽  
Stem Rot ◽  
Late Leaf Spot ◽  
Fact Sheet ◽  
On Farm ◽  
Hamilton County

This ten-page fact sheet includes a summary of various fungicide spray programs for fungal disease control of early leaf spot, late leaf spot, and white mold/stem rot of peanut in 2012-2016 on-farm trials in Hamilton County. Written by K.W. Wynn, N.S. Dufault, and R.L. Barocco and published by the Plant Pathology Department.http://edis.ifas.ufl.edu/pp334

Interactive Effects of Fungicide, Application Timing, and Spray Volume on Peanut Diseases and Yield

2012 ◽  
Vol 13 (1) ◽  
pp. 16
Author(s):  
Joao Augusto ◽  
Timothy B. Brenneman
Keyword(s):  
Arachis Hypogaea ◽  
Leaf Spot ◽  
Interactive Effects ◽  
Stem Rot ◽  
Soilborne Pathogens ◽  
Application Timing ◽  
Yield Increase ◽  
Late Season ◽  
Pod Yield ◽  
Spray Volume

Fungicide penetration of the peanut (Arachis hypogaea) canopy to target soilborne pathogens is difficult due to the dense foliage present when mid- to late-season applications are made. To assess the effect of application timing and volume on leaf spot and stem rot control as well as peanut yield, pyraclostrobin (0.21 kg a.i./ha) or chlorothalonil (1.26 kg a.i./ha), a systemic and a contact fungicide, respectively, were applied four times on cv. Georgia Green during the day (on unfolded leaves) or at night (on folded leaves) at 187, 243, or 355 liters/ha. Night application of pyraclostrobin, across spray volumes, gave the best stem rot control and pod yield increase. Pyraclostrobin applied during the day at higher spray volumes also slightly increased control of stem rot, apparently by improving canopy penetration. Neither application timing nor spray volume affected leaf spot control with pyraclostrobin. Higher spray volumes for the chlorothalonil applications tended to improve control of early and late leaf spot, possibly by increasing coverage of foliage and stems. Accepted for publication 10 January 2012. Published 20 April 2012.

On-Farm Evaluations of Reduced Input Fungicide Programs in Peanut Fields with Low, Moderate, or High Levels of Disease Risk

2014 ◽  
Vol 41 (1) ◽  
pp. 50-57 ◽  
Author(s):  
J. E. Woodward ◽  
T. B. Brenneman ◽  
R. C. Kemerait ◽  
A. K. Culbreath ◽  
N. B. Smith
Keyword(s):  
Leaf Spot ◽  
Cultural Practices ◽  
Disease Risk ◽  
Sclerotium Rolfsii ◽  
Stem Rot ◽  
Cercospora Arachidicola ◽  
Production Region ◽  
Net Returns ◽  
Peanut Production ◽  
On Farm

ABSTRACT In 2003, 2004, and 2005 standard and reduced input fungicide programs were evaluated throughout the peanut production region of Georgia for control of early leaf spot (Cercospora arachidicola), late leaf spot (Cercosporidium personatum), and southern stem rot (Sclerotium rolfsii). Disease risk was determined for each field based on the cultural practices implemented and ranged from low to high. Six to eight fungicide applications were made in the standard programs, versus three to six applications in reduced programs. Leaf spot ratings were higher for the reduced programs in five of the fourteen trials with substantial defoliation occurring in one trial. Overall, southern stem rot control for the reduced programs was equal to or better than that for the standard program, which could be attributed to the differences in fungicide selection or timing. Pod yields for the reduced programs were equal to or greater than the standard programs in all but one trial. Net returns were higher for the reduced programs in half of the trials; however, the reduced program resulted in lower net returns in one trial in 2004. Our results indicate that reduced input fungicide programs can be used to adequately manage fungal diseases of peanut without compromising yield or profitability, and that the use of cultivars with moderate levels of disease resistance may enhance disease control.

scholarly journals Irrigation Timing Impacts the Efficacy of Foliar-Applied Fungicides Toward Foliar and Soilborne Pathogens of Peanut

Plant Disease ◽  
2012 ◽  
Vol 96 (12) ◽  
pp. 1785-1790 ◽  
Author(s):  
J. E. Woodward ◽  
T. B. Brenneman ◽  
B. G. Mullinix
Keyword(s):  
Disease Control ◽  
Leaf Spot ◽  
Southeastern United States ◽  
Sclerotium Rolfsii ◽  
Quadratic Function ◽  
Soilborne Pathogens ◽  
Cercospora Arachidicola ◽  
Lesion Development ◽  
Fungicide Residues ◽  
Fungicide Residue

Fungicides not reaching target organisms result in decreased disease control. In the southeastern United States, foliar-applied fungicides are routinely used to manage peanut (Arachis hypogaea) diseases. Irrigation is often applied to wash fungicides from treated foliage to obtain maximum control of diseases caused by soilborne pathogens. Administering irrigation before fungicide residues have dried may adversely impact foliar disease control. A microplot study was conducted in 2003, 2004, and 2005 to evaluate the redistribution of azoxystrobin, tebuconazole, and flutolanil plus chlorothalonil following different irrigation timings. Standard fungicide regimes were subjected to 1.3-cm of irrigation 0, 6, 12, 24, 48, or 96 h after application, and a nonirrigated control was included. Microplots not receiving irrigation were covered while irrigation treatments were administered. Irrigation timing was significant for the number of early leaf spot (Cercospora arachidicola) lesions per leaf. Leaf spot was more severe when irrigation was administered immediately following fungicide applications, and was significantly reduced with a 6- and 12-h delay prior to an irrigation event, whereas maximum control was obtained when irrigation was delayed for 24 h or later. To further quantify fungicide residue distribution, Sclerotium rolfsii was used to bioassay foliage and pods. Lesion development on leaflets, which was greater for earlier irrigation timings, did not differ for the 12-h and later timings and was generally similar to the nonirrigated controls. Pod colonization for all fungicides increased according to a quadratic function of irrigation timing, with the least colonization occurring at the 0-h timing. Colonization of pods treated with azoxystrobin was similar for all irrigation timings; whereas, suppression was greatest for tebuconazole at earlier irrigation timings. This study demonstrates that irrigation can be used to redistribute fungicides applied to peanut foliage to improve control of soilborne pathogens but administering irrigation within 24 h may decrease leaf spot control.

scholarly journals Management of Late Leaf Spot of Peanut with Benomyl and Chlorothalonil: A Study in Preserving Fungicide Utility

Plant Disease ◽  
2002 ◽  
Vol 86 (4) ◽  
pp. 349-355 ◽  
Author(s):  
A. K. Culbreath ◽  
K. L. Stevenson ◽  
T. B. Brenneman
Keyword(s):  
Leaf Spot ◽  
Fungicide Resistance ◽  
Field Experiments ◽  
Resistance Management ◽  
Model System ◽  
Systemic Fungicide ◽  
Cercospora Arachidicola ◽  
Pathogen Population ◽  
Late Leaf Spot ◽  
Sterol Biosynthesis Inhibitor

Recent registration of sterol biosynthesis inhibitor and strobilurin fungicides for control of early (Cercospora arachidicola) and late (Cercosporidium personatum) leaf spot diseases of peanut (Arachis hypogaea) has renewed interest in the potential for loss of disease control due to fungicide resistance. The objectives of this study were to use the systemic fungicide benomyl, the protectant fungicide chlorothalonil, and late leaf spot of peanut as a model system to compare fungicide application strategies for fungicide resistance management. Field experiments were conducted at Tifton and Plains, GA, in 1995 and 1996 to determine the effects of alternate applications, mixtures, and alternating block applications of chlorothalonil and benomyl compared with full-season applications of two rates of chlorothalonil and two rates of benomyl alone on late leaf spot of peanut and on the proportion of the pathogen population resistant to benomyl following the various regimes. Tank mix combinations of half rates of the two fungicides and alternations of the full rates of the two fungicides provided better (P ≤ 0.05) control of late leaf spot than full-season applications of either rate of benomyl alone, and were comparable to full rates of chlorothalonil alone. Neither tank mixes nor alternating sprays prevented an increase in the relative frequency of benomyl-resistant isolates compared with other treatments in which benomyl was used. Both mixtures and alternate applications of chlorothalonil and benomyl were effective for management of leaf spot in fields where benomyl alone did not provide season-long leaf spot control.

Effect of In-Furrow and Early-Season Banded Applications of Fungicides on Incidence of Early Leaf Spot of Peanut

2015 ◽  
Vol 16 (4) ◽  
pp. 225-229
Author(s):  
Albert K. Culbreath ◽  
Robert C. Kemerait ◽  
Yun-Ching Tsai ◽  
Timothy B. Brenneman ◽  
Katherine L. Stevenson ◽  
...  
Keyword(s):  
Arachis Hypogaea ◽  
Leaf Spot ◽  
Field Experiments ◽  
Disease Incidence ◽  
Cercospora Arachidicola ◽  
Early Season ◽  
Fungicide Application

Field experiments were conducted in Tifton, GA, in 2012-2014 to determine the effect of in-furrow applications of prothioconazole and early-season banded applications of prothioconazole or pyraclostrobin on incidence of early leaf spot (Cercospora arachidicola) of peanut (Arachis hypogaea). In each year, border rows were planted in May as a source of inoculum for plants in the treatment plots. Plots were planted in August or September after epidemics of early leaf spot were severe in the border plots. Fungicide application regimes included two rates (100 and 200 g a.i./ha) of prothioconazole applied in-furrow at planting, and 200 g a.i./ha of prothioconazole or 164 g a.i./ha of pyraclostrobin applied concentrated in a 30-cm band 21 days after planting (DAP). Incidence (percent of leaflets with one or more leaf spot) of early leaf spot was monitored until 54 to 57 days after planting in each year. In all years, disease incidence was below 10% at 28 DAP in plots treated with 200 g a.i./ha of prothioconazole in-furrow compared to over 40% in nontreated plots at the same time. In-furrow applications of 100 g a.i./ha of prothioconazole were less effective, but suppressed leaf spot incidence compared to the control. Banded applications of either fungicide at 21 DAP resulted in a decrease in leaf spot incidence, and prevented increase in leaf spot incidence for 19 days or longer. Accepted for publication 30 November 2015. Published 3 December 2015.

Calendar and AU-Pnuts Advisory Programs Compared for Leaf Spot Diseases and Rust Control on Peanut in Southwest Alabama

2006 ◽  
Vol 7 (1) ◽  
pp. 3
Author(s):  
A. K. Hagan ◽  
H. L. Campbell ◽  
K. L. Bowen ◽  
M. Pegues
Keyword(s):  
Disease Control ◽  
Leaf Spot ◽  
Weather Conditions ◽  
Treatment Schedule ◽  
Advisory Programs ◽  
Fungicide Application ◽  
Leaf Spots ◽  
Production Area ◽  
Peanut Production ◽  
Rain Events

Peanut production acreage has increased substantially in southwest Alabama in the past several years. Since prevailing weather conditions in this newer production area are conducive to peanut diseases, primarily due to frequent rainfall during summer months, a 2-week calendar fungicide treatment schedule is considered essential to controlling leaf spot diseases and rust in order to optimize yields. In 2003, 2004, and 2005, extended calendar application intervals and the AU-Pnuts leaf spot advisory were compared with the recommended 2-week calendar schedule for peanut disease control on partially disease-resistant peanut cultivars (DP-1 in 2003 and Florida C99R in 2004 and 2005). Fungicide programs included recommended rates of azoxystrobin, chlorothalonil, and tebuconazole. Numbers of fungicide applications for the 2-, 3-, and 4-week calendar schedule treatments were 7, 5, and 4, respectively in each year. Fungicide applications made according to AU-Pnuts are based on rain events and resulted in 5 sprays in 2003 and 7 sprays in 2004 and 2005. Fungicide application schedule had a significant impact on leaf spots, rust, southern stem rot and yield in at least two of the three study years. Results indicate that recommendations for the 2-week fungicide application schedule should be maintained in this area. Fungicide program also had a consistent effect on measured variables, with the azoxystrobin program providing better disease control and higher yields. Accepted for publication 16 August 2006. Published 10 November 2006.

scholarly journals SEVERITY OF RAMULARIA LEAF SPOT AND SEED COTTON YIELD IN DIFFERENT SOWING TIMES

2016 ◽  
Vol 29 (3) ◽  
pp. 603-610 ◽  
Author(s):  
JOÃO PAULO ASCARI ◽  
DEJÂNIA VIEIRA DE ARAÚJO ◽  
LEONARDO DIOGO EHLE DIAS ◽  
GIOVANI JUNIOR BAGATINI ◽  
INÊS ROEDER NOGUEIRA MENDES
Keyword(s):  
Disease Control ◽  
Leaf Spot ◽  
Cotton Yield ◽  
Yield Losses ◽  
Seed Cotton ◽  
Sowing Time ◽  
Fungicide Application ◽  
Progress Curve ◽  
Ramularia Leaf Spot ◽  
Diagrammatic Scale

ABSTRACT The ramularia leaf spot (RLS) disease causes cotton yield losses. Choosing a less susceptible cultivar and a sowing time that are less favorable to the pathogen contribute to the management of this disease. The objective of this work was to evaluate the severity of ramularia leaf spot on cotton cultivars sowed in two different times. The experiment was conducted in a triple factorial design (4x3x2), consisted of four cultivars, the three thirds of the plant and two sowing times, with four replications. Each plot was divided in two twin plots, one with fungicide application (with disease control) and the other without fungicide application (without disease control). The severity assessments were performed every seven days, considering each third of the plant with a diagrammatic scale. Yield was evaluated in each plot. There was a significant interaction between sowing times and the thirds of the plant in the plots without disease control for RLS severity, with the highest values of area under the disease progress curve (AUDPC) in the first sowing time (ST1) and in the lower third of the plant. The FMT705 cultivar had the highest and FM951LL the lowest value of AUDPC. The AUDPC of these cultivars were no statistically different in the second sowing time (ST2), but they had higher AUDPC values in the lower third. Highest yields were found with ST1 in plots with disease control, with no differences between the cultivars, however, lower yields were found in plots without disease control.

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