scholarly journals Fungicides and Application Timing for Control of Early Leafspot, Southern Blight, andSclerotiniaBlight of Peanut

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
W. James Grichar ◽  
Jason E. Woodward
Keyword(s):  
Disease Control ◽  
Systems Approach ◽  
Sclerotium Rolfsii ◽  
Field Studies ◽  
Yield Response ◽  
High Dose ◽  
Cercospora Arachidicola ◽  
Application Timing ◽  
Southern Blight ◽  
Soilborne Disease

Field studies were conducted in 2013 and 2014 in south Texas near Yoakum and from 2008 to 2011 in central Texas near Stephenville to evaluate various fungicides for foliar and soilborne disease control as well as peanut yield response under irrigation. Control ofSclerotiniablight caused bySclerotinia minorJagger with penthiopyrad at 1.78 L/ha was comparable to fluazinam or boscalid; however, the 1.2 L/ha dose of penthiopyrad did not provide consistent control. Peanut yield was reduced with the lower penthiopyrad dose when compared with boscalid, fluazinam, or the high dose of penthiopyrad. Control of early leaf spot, caused byCercospora arachidicolaS. Hori or southern blight, caused bySclerotium rolfsiiSacc., with penthiopyrad in a systems approach was comparable with propiconazole, prothioconazole, or pyraclostrobin systems and resulted in disease control that was higher than the nontreated control. Peanut yield was also comparable with the penthiopyrad, propiconazole, prothioconazole, or pyraclostrobin systems and reflects the ability of the newer fungicides to control multiple diseases found in Texas peanut production.

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.

Effects of Application Timing and Method on Control of Southern Stem Rot of Peanut With Foliar-Applied Fungicides1

1991 ◽  
Vol 18 (1) ◽  
pp. 47-50 ◽  
Author(s):  
A. K. Hagan ◽  
J. R. Weeks ◽  
K. Bowen
Keyword(s):  
Disease Control ◽  
Sclerotium Rolfsii ◽  
The Other ◽  
Stem Rot ◽  
Yield Response ◽  
Application Timing ◽  
Similar Disease

Abstract Foliar-applied flutolanil, diniconazole, tebuconazole, and propiconazole were compared to granular PCNB for the control of southern stem rot (Sclerotium rolfsii) and their effects on yield of peanut in 1988 and 1989 in southeastern Alabama. Numbers of stem rot loci were significantly decreased and yields were increased in plots treated with banded and broadcast applications of flutolanil, diniconazole, and tebucnzole. While yields of flutolanil-, diniconazole-, and tebuconazole-treated plots were significantly higher than the PCNB-treated plots, efficacy of these fungicides in controlling southern stem rot differed only in one of two years. Banded applications of flutolanil gave similar disease control but yielded less than broadcast applications of the same fungicide. Disease control and yield response with propiconazole was comparable to that obtained with PCNB in one of two years and proved far less efficacious against stem rot than the other fungicides evaluated.

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 Pre- and Postinfection Activity of Fungicides in Control of Hop Downy Mildew

Plant Disease ◽  
2015 ◽  
Vol 99 (6) ◽  
pp. 858-865 ◽  
Author(s):  
David H. Gent ◽  
Megan C. Twomey ◽  
Sierra N. Wolfenbarger ◽  
Joanna L. Woods
Keyword(s):  
Disease Control ◽  
Downy Mildew ◽  
Field Experiments ◽  
Resistance Management ◽  
Field Studies ◽  
Similar Efficacy ◽  
Application Timing ◽  
Pseudoperonospora Humuli ◽  
Hazard Warnings ◽  
Post Hoc

Optimum timing and use of fungicides for disease control are improved by an understanding of the characteristics of fungicide physical mode of action. Greenhouse and field experiments were conducted to quantify and model the duration of pre- and postinfection activity of fungicides most commonly used for control of hop downy mildew (caused by Pseudoperonospora humuli). In greenhouse experiments, control of downy mildew on leaves was similar among fungicides tested when applied preventatively but varied depending on both the fungicide and the timing of application postinfection. Disease control decreased as applications of copper were made later after inoculation. In contrast, cymoxanil, trifloxystrobin, and dimethomorph reduced disease with similar efficacy when applied 48 h after inoculation compared with preventative applications of these fungicides. When fungicides were applied 72 h after inoculation, only dimethomorph reduced the sporulating leaf area similarly to preinoculation application timing. Adaxial chlorosis, necrosis, and water soaking of inoculated leaves, indicative of infection by P. humuli, were more severe when plants were treated with cymoxanil, trifloxystrobin, and dimethomorph 48 to 72 h after inoculation, even though sporulation was suppressed. Trifloxystrobin and dimethomorph applied 72 h after inoculation suppressed formation of sporangia on sporangiophores as compared with all other treatments. In field studies, dimethomorph, fosetyl-Al, and trifloxystrobin suppressed development of shoots with systemic downy mildew to the greatest extent when applied near the timing of inoculation, although the duration of preventative and postinfection activity varied among the fungicides. There was a small reduction in efficacy of disease control when fosetyl-Al was applied 6 to 7 days after inoculation as compared with protective applications. Trifloxystrobin had 4 to 5 days of preinfection activity and limited postinfection activity. Dimethomorph had the longest duration of protective activity. Percent disease control was reduced progressively with increasing time between inoculation and application of dimethomorph. These findings provide guidance to the use of fungicides when applications are timed with forecasted or post hoc disease hazard warnings, as well as guidance on tank-mixes of fungicides that may be suitable both for resistance management considerations and extending intervals between applications.

scholarly journals Southern Blight (Sclerotium rolfsiiSacc.) of Cowpea: Genetic Characterization of Two Sources of Resistance

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Richard L. Fery ◽  
Philip D. Dukes
Keyword(s):  
Resistance Genes ◽  
Sclerotium Rolfsii ◽  
Field Studies ◽  
Sources Of Resistance ◽  
Frequency Distributions ◽  
Southern Blight ◽  
Segregation Data ◽  
Cowpea Cultivars ◽  
Dominant Genes

Field studies were conducted to characterize the genetic nature of resistance to southern blight (caused bySclerotium rolfsiiSacc.) exhibited by the cowpea [Vigna unguiculata(L.) Walp.] cultivars Carolina Cream and Brown Crowder and to determine if a genetic relationship exists for this resistance between the two cultivars. Examination of the comparative frequency distributions of the parental and progeny populations of the “Carolina Cream” x “Magnolia Blackeye” and “Brown Crowder” x “Magnolia Blackeye” crosses and the corresponding segregation data indicates that the southern blight resistances exhibited by “Carolina Cream” and “Brown Crowder” are conditioned by single dominant genes. Examination of the segregation data from the parental and progeny populations of the “Carolina Cream” x “Brown Crowder” cross suggests that the two resistance genes are not allelic. The availability of each of the resistance genes in cultivar-type genetic backgrounds should allow for rapid incorporation of southern blight resistance genes into other cowpea cultivars by the application of conventional plant breeding methodologies.

scholarly journals Number of Tebuconazole Applications for Maximizing Disease Control and Yield of Peanut in Growers' Fields in Alabama

Plant Disease ◽  
1997 ◽  
Vol 81 (8) ◽  
pp. 927-931 ◽  
Author(s):  
K. L. Bowen ◽  
A. K. Hagan ◽  
J. R. Weeks
Keyword(s):  
Disease Control ◽  
Sclerotium Rolfsii ◽  
Stem Rot ◽  
Cercospora Arachidicola ◽  
Quadratic Equations ◽  
Leaf Spots ◽  
Minimal Disease ◽  
Yield Maximization

Disease and yields of peanut were monitored in growers' fields treated with zero, one, two, three, and four applications of tebuconazole. Yields ranged from 1,918 to 6,891 kg/ha and averaged 4,319 kg/ha over eight locations in 3 study years. Defoliation caused by peanut leaf spots (Cercospora arachidicola and Cercosporidium acutatum) and incidence of southern stem rot (Sclerotium rolfsii) were inversely related to number of tebuconazole applications, while yield was directly related to number of tebuconazole applications. Average yields with zero, one, two, and four tebuconazole applications (each application at 0.25 kg a.i./ha) were 3,609, 4,088, 4,526, and 4,868 kg/ha, respectively. Data from each location were best modeled by quadratic equations allowing determination of numbers of tebuconazole applications for minimal disease and maximal yields. Calculated spray numbers indicate that between three and four applications of tebuconazole is best for disease control and yield maximization.

Influence of Diclosulam Postemergence Application Timing on Weed Control and Peanut Tolerance

2006 ◽  
Vol 20 (3) ◽  
pp. 651-657 ◽  
Author(s):  
Wesley J. Everman ◽  
Scott B. Clewis ◽  
Zachary G. Taylor ◽  
John W. Wilcut
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Field Studies ◽  
Yield Potential ◽  
Yield Response ◽  
Early Season ◽  
Common Ragweed ◽  
Application Timing ◽  
Common Lambsquarters ◽  
Free Environment

Field studies were conducted at Lewiston–Woodville and Rocky Mount, NC in 2001 and 2002 to evaluate weed control and peanut response to POST treatments of diclosulam at various rates and application timings. Diclosulam controlled common ragweed and entireleaf morningglory when applied within 35 d after planting (DAP). Common ragweed 61 cm tall was controlled ≥92% with 4 to 13 g ai/ha diclosulam and larger common ragweed (107 to 137 cm tall) were controlled ≥97% with 27 g/ha diclosulam. Common lambsquarters was controlled 62% or less with all diclosulam POST treatments following metolachlor applied PRE, which provided 48% control. Peanut injury was less than 15% with all diclosulam POST treatments and was transitory. In separate studies, POST diclosulam treatments did not affect peanut yield in a weed-free environment. Peanut yield in weedy environments was reduced as the diclosulam application timing was delayed because of early season weed interference. A linear relationship was observed between yield and application timing with yield decreasing as application timing was delayed. This yield response documents the importance of early season weed management for maximizing peanut yield potential. Virginia peanut varieties were not affected by different POST rates of diclosulam; however, early season peanut injury showed a linear and quadratic relationship with diclosulam rate and was less than 14% at rates as high as 71 g/ha, and was not apparent by late season.

Effect of Benzovindiflupyr + Azoxystrobin + Propiconazole Fungicide Applied at Different Growth Stages on Foliar Disease Severity, Grain Yield, and Economic Benefit of Hybrid Corn Grown in Kentucky

2020 ◽  
Vol 21 (3) ◽  
pp. 162-165
Author(s):  
Carl A. Bradley ◽  
Richard C. Kenimer ◽  
Jordan M. Shockley ◽  
Kiersten A. Wise
Keyword(s):  
Disease Control ◽  
Cost Effective ◽  
Field Trials ◽  
Yield Response ◽  
Growth Stages ◽  
Single Application ◽  
Hybrid Corn ◽  
Foliar Disease ◽  
Application Timing ◽  
Different Growth Stages

Field trials were conducted across nine different environments in Kentucky in 2017 and 2018 that evaluated a fungicide containing benzovindiflupyr + azoxystrobin + propiconazole applied to hybrid corn (Zea mays) at the six-leaf collar stage (V6) or at silking (R1) and a sequential application timing (V6 + R1). Results indicated that treatments that included an R1 application provided the best foliar disease control and were the only treatments that preserved yields compared with the nontreated control. A single application at R1 did not differ from the sequential V6 + R1 application for disease control or yield response, suggesting that Kentucky corn growers likely can rely on a more cost-effective single fungicide application at R1 for foliar disease management and improve return on fungicide investment rather than making multiple applications at different timings.

scholarly journals Effect of Placement and Rate of PCNB and PCNB + Ethoprop On The Control Of Southern Stem Rot Of Peanut1

1991 ◽  
Vol 18 (2) ◽  
pp. 94-97 ◽  
Author(s):  
A. K. Hagan ◽  
J. R. Weeks ◽  
K. Bowen
Keyword(s):  
Disease Control ◽  
Narrow Band ◽  
Sclerotium Rolfsii ◽  
Wide Band ◽  
Band Width ◽  
Stem Rot ◽  
Yield Response ◽  
Control Disease ◽  
On Farm

Abstract Pentachloronitrobenzene (PCNB) 10G and PCNB + ethoprop 10–3G applied on 10-cm (narrow) and 25-cm (wide) band widths, respectively, were evaluated for the control of southern stem rot (Sclerotium rolfsii) and impact on yield of peanut. On-farm evaluations with PCNB were done in 1988 to 1990, while PCNB + ethoprop and diniconazole 25W were tested in 1989 and 1990. Narrow band width (10-cm) applications of the 5.6 kg a.i./ha rate of PCNB significantly reduced disease and increased yield all three years compared to the control; the 11.2 kg a.i./ha rate applied on the wide band width (25-cm) reduced stem rot incidence two of three years. The narrow and wide band width applications of PCNB + ethoprop at 5.6 + 1.7 kg a.i./ha and 11.2 + 3.3 kg a.i./ha resulted in reduced southern stem rot incidence and higher yields than the control. Disease control and yield response with PCNB + ethoprop were similar to those in plots treated with PCNB on the narrow and wide band widths. Diniconazole 25W, which was broadcast twice at 0.28 kg a.i./ha in 1989 and 1990, gave better disease control and higher yields than PCNB and PCNB + ethoprop only one of two years.

scholarly journals Assessment of New Fungicides for the Control of Southern Blight on Aucuba

1999 ◽  
Vol 17 (2) ◽  
pp. 73-75
Author(s):  
A. K. Hagan ◽  
J. W. Olive
Keyword(s):  
Disease Control ◽  
Sclerotium Rolfsii ◽  
Test Period ◽  
Effective Control ◽  
Southern Blight ◽  
Aucuba Japonica ◽  
Industry Standard ◽  
Causal Fungus

Abstract Drenches of Lynx 3.6F, ProStar 50W, Fluazinam 500F, Terraguard 50W, and Curalan DF were compared with Terraclor 75W for the control of southern blight on container-grown aucuba (Aucuba japonica) ‘Variegata’. Over the three-year test period, ProStar 50W and Fluazinam 500F across a range of rates completely protected aucuba from attack by the causal fungus, Sclerotium rolfsii. Also, both fungicides gave better disease control in two of three years than the current industry standard Terraclor 75W. Lynx 3.6F at the 0.54 g a.i./liter rate proved as effective in controlling southern blight as ProStar 50W and Fluazinam 500F. Terraclor 75W, which was applied at over twice the labeled drench rate, gave inconsistent disease control. Terraguard 50W and Curalan DF failed to provide effective control of southern blight on aucuba. No symptoms of phytotoxicity were observed.

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