Effect of Maize Hybrid and Foliar Fungicides on Yield Under Low Foliar Disease Severity Conditions

Foliar fungicide use in the U.S. Corn Belt increased in the last decade; however, questions persist pertaining to its value and sustainability. Multistate field trials were established from 2010 to 2012 in Illinois, Iowa, Ohio, and Wisconsin to examine how hybrid and foliar fungicide influenced disease intensity and yield. The experimental design was in a split-split plot with main plots consisting of hybrids varying in resistance to gray leaf spot (caused by Cercospora zeae-maydis) and northern corn leaf blight (caused by Setosphaera turcica), subplots corresponding to four application timings of the fungicide pyraclostrobin, and sub-subplots represented by inoculations with either C. zeae-maydis, S. turcica, or both at two vegetative growth stages. Fungicide application (VT/R1) significantly reduced total disease severity relative to the control in five of eight site-years (P < 0.05). Disease was reduced by approximately 30% at Wisconsin in 2011, 20% at Illinois in 2010, 29% at Iowa in 2010, and 32 and 30% at Ohio in 2010 and 2012, respectively. These disease severities ranged from 0.2 to 0.3% in Wisconsin in 2011 to 16.7 to 22.1% in Illinois in 2010. The untreated control had significantly lower yield (P < 0.05) than the fungicide-treated in three site-years. Fungicide application increased the yield by approximately 6% at Ohio in 2010, 5% at Wisconsin in 2010 and 6% in 2011. Yield differences ranged from 8,403 to 8,890 kg/ha in Wisconsin 2011 to 11,362 to 11,919 kg/ha in Wisconsin 2010. Results suggest susceptibility to disease and prevailing environment are important drivers of observed differences. Yield increases as a result of the physiological benefits of plant health benefits under low disease were not consistent.

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Control of speckled leaf blotch of wheat with fungicides

New Zealand Plant Protection ◽

10.30843/nzpp.2000.53.3621 ◽

2000 ◽

Vol 53 ◽

pp. 103-108

Author(s):

M.G. Cromey ◽

M. Braithwaite ◽

B.J.R. Alexander ◽

S. Ganev ◽

T.R. Cookson

Keyword(s):

Disease Severity ◽

Total Yield ◽

Field Trials ◽

Growth Stages ◽

The South ◽

Leaf Blotch ◽

Fungicide Application ◽

Low Levels ◽

Disease Pressure

Two field trials were conducted in autumnsown wheat cv Domino which is highly susceptible to speckled leaf blotch in Central and South Canterbury Eighteen fungicide treatments were applied at two growth stages (tillering and ear emergence) at the manufacturers recommended rates Severity of speckled leaf blotch and other diseases was assessed on several occasions Speckled leaf blotch was severe in the South Canterbury trial but only low levels of the disease were recorded in the central Canterbury trial Most fungicides reduced disease severity and increased yield especially in the South Canterbury trial where disease pressure was highest and yield increases greater than 30 were recorded The second fungicide application appeared to provide most of the increase in yield The increases in thousand grain weights following fungicide applications contributed approximately onethird of the total yield increases in the South Canterbury trial and half in the Central Canterbury trial

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Assessing Late Vegetative and Tasseling Fungicide Application Timings on Foliar Disease and Yield in Indiana Corn

Plant Health Progress ◽

10.1094/php-03-20-0022-rs ◽

2020 ◽

Vol 21 (4) ◽

pp. 224-229

Author(s):

Darcy E. P. Telenko ◽

Jeffrey D. Ravellette ◽

Kiersten A. Wise

Keyword(s):

Leaf Spot ◽

The United States ◽

Field Trials ◽

Gray Leaf Spot ◽

Corn Production ◽

Foliar Disease ◽

Application Timing ◽

Cercospora Zeae Maydis ◽

Foliar Fungicide ◽

Disease Pressure

Gray leaf spot (Cercospora zeae-maydis) is a foliar disease of corn (Zea mays) that consistently reduces yields across the United States and is an annual concern in Indiana corn production. Field trials were conducted in West Lafayette, IN, over 3 years (2016 to 2018) to evaluate the effectiveness of 12-leaf collar stage (V12) foliar fungicide applications compared with tasseling (VT) applications for gray leaf spot management and yield. Results indicated that during years in which foliar disease severity was less than 4%, there was no effect of application timing on gray leaf spot severity. In 2018, when gray leaf spot levels exceeded 5%, significantly less disease was observed in treatments receiving VT applications compared with V12 applications. Application timing did not affect yield in any year of the experiment. In 2016, benzovindiflupyr + azoxystrobin + propiconazole resulted in greater yields compared with the nontreated control, and in 2018, pyraclostrobin + metconazole and benzovindiflupyr + azoxystrobin + propiconazole resulted in greater yields compared with the nontreated control. This research indicates that in high disease pressure environments and years, Indiana farmers may want to continue to apply fungicides at VT rather than apply prior to tassel.

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Validation of Consensus Quantitative Trait Loci Associated with Resistance to Multiple Foliar Pathogens of Maize

Phytopathology ◽

10.1094/phyto-99-5-0540 ◽

2009 ◽

Vol 99 (5) ◽

pp. 540-547 ◽

Cited By ~ 14

Author(s):

Godfrey Asea ◽

Bindiganavile S. Vivek ◽

George Bigirwa ◽

Patrick E. Lipps ◽

Richard C. Pratt

Keyword(s):

Quantitative Trait Loci ◽

Disease Severity ◽

Quantitative Trait ◽

Gray Leaf Spot ◽

Sub Saharan Africa ◽

Maize Production ◽

Resistant Parent ◽

Trait Loci ◽

Sub Saharan ◽

Corn Leaf Blight

Maize production in sub-Saharan Africa incurs serious losses to epiphytotics of foliar diseases. Quantitative trait loci conditioning partial resistance (rQTL) to infection by causal agents of gray leaf spot (GLS), northern corn leaf blight (NCLB), and maize streak have been reported. Our objectives were to identify simple-sequence repeat (SSR) molecular markers linked to consensus rQTL and one recently identified rQTL associated with GLS, and to determine their suitability as tools for selection of improved host resistance. We conducted evaluations of disease severity phenotypes in separate field nurseries, each containing 410 F2:3 families derived from a cross between maize inbred CML202 (NCLB and maize streak resistant) and VP31 (a GLS-resistant breeding line) that possess complimentary rQTL. F2:3 families were selected for resistance based on genotypic (SSR marker), phenotypic, or combined data and the selected F3:4 families were reevaluated. Phenotypic values associated with SSR markers for consensus rQTL in bins 4.08 for GLS, 5.04 for NCLB, and 1.04 for maize streak significantly reduced disease severity in both generations based on single-factor analysis of variance and marker-interval analysis. These results were consistent with the presence of homozygous resistant parent alleles, except in bin 8.06, where markers were contributed by the NCLB-susceptible parent. Only one marker associated with resistance could be confirmed in bins 2.09 (GLS) and 3.06 (NCLB), illustrating the need for more robust rQTL discovery, fine-mapping, and validation prior to undertaking marker-based selection.

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Effect of Foliar Fungicides Applied at Silking on Stalk Lodging in Corn

Plant Health Progress ◽

10.1094/php-08-19-0049-rs ◽

2020 ◽

Vol 21 (1) ◽

pp. 2-8

Author(s):

Alison E. Robertson ◽

Mauricio Serrano ◽

Jyotsna Acharya ◽

John Shriver ◽

John Beckman ◽

...

Keyword(s):

Zea Mays L ◽

Field Trials ◽

State University ◽

Iowa State University ◽

Resistance Development ◽

Stalk Rot ◽

Fungicide Application ◽

Foliar Fungicide ◽

Stalk Lodging ◽

Plot Design

Stalk lodging in corn (Zea mays L.) leads to harvest complications and yield losses. Farmers who apply a foliar fungicide to manage leaf diseases have also observed reduced lodging. The goal of this study was to evaluate the effect of a foliar fungicide applied at silking on percent lodging. Field trials were established on Iowa State University Research Farms in 2016 and 2017. Treatments evaluated were foliar fungicide application (with or without) and harvest date (corn harvested at weekly intervals for up to 5 weeks); a split plot design was used with four complete blocks. Across all locations and years, a fungicide application significantly reduced mean lodging (P < 0.0001) by 9.3% and increased yields (P = 0.0043) by an average of 258.3 kg/ha (4.1 bu/acre). Percent lodging increased as harvest was delayed (P < 0.0001). This study demonstrated that foliar fungicides applied at silking reduced lodging and thus confirmed observations of farmers. Applying a fungicide to reduce lodging and favor harvest, however, is not recommended due to risk of fungicide resistance development and the lack of efficacy on stalk rot pathogens.

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Cultivar response to fungicide application in relation to rice blast control, productivity and sustainability

Pesquisa Agropecuária Brasileira ◽

10.1590/s0100-204x2003000100002 ◽

2003 ◽

Vol 38 (1) ◽

pp. 11-17 ◽

Cited By ~ 8

Author(s):

Anne Sitarama Prabhu ◽

Marta Cristina Filippi ◽

Francisco José Pfeilsticker Zimmermann

Keyword(s):

Grain Yield ◽

Rice Blast ◽

Field Trials ◽

Yield Response ◽

Fungicide Treatment ◽

Fungicide Application ◽

Progress Curve ◽

Panicle Blast ◽

Sustainable Value ◽

Foliar Fungicide

Four field trials were conducted, from 1995 to 1997, with the objective of studying the response of four upland cultivars to foliar fungicide application in relation to panicle blast control, grain yield and sustainability. Differential disease control and yield response of cultivars to fungicide treatment were obtained. Losses in grain yield of cultivars IAC 202, Caiapó, Rio Paranaíba and Araguaia due to panicle blast were 44.8%, 27.4%, 24.4% and 18.2%, respectively. Two applications of tricyclazole or benomyl controlled panicle blast, as indicated by lower values of disease progress curve and relative panicle blast severity, and increased grain yield of the cultivar IAC 202. The losses in 100 panicle grain weight and grain yield were significantly reduced by 22.3% and 25.1% in IAC 202 and 23.6% and 20.5% in Caiapó, respectively, with two sprays of tricyclazole. Sustainable value index for yield was maximum with two applications of tricyclazole (0.59), followed by one application at booting (0.46) and at heading (0.40) in cultivar IAC 202. Results showed no yield response of the cultivars Rio Paranaíba and Araguaia to fungicide applications for panicle blast control.

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Effect of Foliar Fungicides on Hail-damaged Corn

Plant Health Progress ◽

10.1094/php-rs-15-0046 ◽

2016 ◽

Vol 17 (1) ◽

pp. 6-12 ◽

Cited By ~ 3

Author(s):

Adam J. Sisson ◽

Yuba R. Kandel ◽

Alison E. Robertson ◽

Chad E. Hart ◽

Amy Asmus ◽

...

Keyword(s):

Disease Severity ◽

Cost Benefit Analysis ◽

Cost Benefit ◽

Growth Stages ◽

Benefit Analysis ◽

Economic Returns ◽

Foliar Disease ◽

Fungicide Application ◽

Positive Economic ◽

Hail Damage

To test if fungicide applied to hail-injured corn improves yield and reduces disease, we simulated hail at VT and R2 growth stages for three years at three Iowa locations for a total of five site years. Hail damage was simulated using a string trimmer or an ice-propelling machine and non-hail controls were included. Estimated defoliation ranged from 5 to 51%, along with ear and stalk injury. After hail events, Headline AMP fungicide (pyraclostrobin + metconazole) was applied at an “immediate” or “deferred” timing (averaging 3 and 8 days afterwards, respectively). A non-fungicide treated control was included in hailed and non-hail control plots. Hail injury reduced fungal foliar disease compared to plants without hail injury, although overall disease severity was low during this study. Hail events at VT or R2 decreased yield compared to control plots (P = 0.1). Fungicide application did not provide yield-increasing plant health benefits after VT and R2 hail, at either “immediate” or “deferred” timing. While yield differences were not statistically significant, a cost/benefit analysis showed deferred fungicide application after VT hail, and immediate and deferred applications after VT for non-hail plots did provide positive economic returns. Results will help inform decisions about fungicide use in hail-damaged corn when foliar diseases are not present at high levels. Accepted for publication 7 January 2016. Published 13 January 2016.

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Effect of Foliar Fungicide and Insecticide on Hail-Damaged Soybean

Plant Health Progress ◽

10.1094/php-rs-16-0012 ◽

2016 ◽

Vol 17 (2) ◽

pp. 141-148

Author(s):

Adam J. Sisson ◽

Yuba R. Kandel ◽

Chad E. Hart ◽

Amy Asmus ◽

Stith N. Wiggs ◽

...

Keyword(s):

Disease Severity ◽

Growth Stage ◽

Yield Loss ◽

Brown Spot ◽

Growth Stages ◽

Economic Return ◽

Foliar Disease ◽

Hail Damage ◽

Seed Moisture ◽

Foliar Fungicide

A fungicide (pyraclostrobin) and an insecticide (alpha-cypermethrin) were applied alone or in combination to hail-injured soybean to determine if yield could be preserved or foliar disease prevented. Pesticides were applied at approximately R3 growth stage and hail injury was simulated with an ice-propelling machine at approximately R1 and R4 growth stages over three years at three Iowa locations. Disease severity was low throughout the study, and included Septoria brown spot, downy mildew, and Cercospora leaf blight. Differences in disease severity among treatments receiving hail and those that did not receive hail were not consistently detected. More importantly, foliar disease severity did not differ among pesticide treatments and untreated controls. Simulated hail caused significant (P = 0.1) yield loss. No difference in yield was observed between untreated and pesticide-treated plots within hail events, except for two site years when hail damage occurred at R1. Seed moisture was generally higher in plots with R1 hail damage. Fungicide and insecticide applied in combination to hail-damaged soybean was more likely to result in a positive economic return than either applied alone. Based on results, R3 fungicide application to soybean injured by hail at R1 or R4 will likely provide little yield-preserving or disease-limiting benefits when foliar disease severity is low. Accepted for publication 21 April 2016. Published 20 June 2016.

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Managing Foliar Diseases of Processing Sweet Corn in New York with Strobilurin Fungicides

Plant Disease ◽

10.1094/pdis-94-2-0213 ◽

2010 ◽

Vol 94 (2) ◽

pp. 213-220 ◽

Cited By ~ 10

Author(s):

D. A. Shah ◽

H. R. Dillard

Keyword(s):

New York ◽

Disease Severity ◽

Sweet Corn ◽

Cost Effective ◽

Field Trials ◽

Leaf Blight ◽

Foliar Disease ◽

Northern Corn Leaf Blight ◽

Strobilurin Fungicides ◽

Corn Leaf Blight

Processing sweet corn (Zea mays) growers in New York are more concerned about the cost effectiveness of fungicide use against foliar fungal diseases (common rust and Northern corn leaf blight) and less about whether such sprays will reduce disease intensity. To address this concern, field trials were done in 2006 and 2007 with three processing sweet corn hybrids (Jubilee, Bold, and GH 9597) that differed in susceptibility to common rust and Northern corn leaf blight, and two strobilurin fungicides (azoxystrobin and pyraclostrobin). Single strobilurin applications were applied in response to foliar disease severity thresholds of 1, 10, and 20%. Single fungicide applications did reduce foliar disease severities. Applications were most cost effective when made in response to the 1 and 10% foliar severity thresholds, and generally only in the susceptible hybrid Bold. Spraying at the 20% severity threshold did reduce final foliar disease severity but was not cost effective. Azoxystrobin and pyraclostrobin were equally effective in disease management. The results suggest that a single application of a strobilurin fungicide against common rust and Northern corn leaf blight can be cost effective for New York processing sweet corn growers when such an application is made before foliar disease severity exceeds 20%.

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Effect of Foliar Fungicides on Corn with Simulated Hail Damage

Plant Disease ◽

10.1094/pdis-94-1-0083 ◽

2010 ◽

Vol 94 (1) ◽

pp. 83-86 ◽

Cited By ~ 26

Author(s):

C. A. Bradley ◽

K. A. Ames

Keyword(s):

Environmental Protection Agency ◽

Field Research ◽

The United States ◽

Gray Leaf Spot ◽

Protection Agency ◽

Quinone Outside Inhibitor ◽

Hail Damage ◽

Cercospora Zeae Maydis ◽

Corn Plants ◽

Physiological Benefits

Quinone outside inhibitor (QoI) foliar fungicides can be effective at reducing foliar diseases in corn (Zea mays), and they have been shown to provide physiological benefits experimentally in other crops in the absence of disease. A new supplemental label for pyraclostrobin that was approved in January 2009 by the United States Environmental Protection Agency (EPA) states that corn plants applied with pyraclostrobin may have better tolerance to damage caused by hail. To determine the effects of QoI foliar fungicides on hail-damaged corn, field research trials were conducted near Champaign, IL in 2007 and 2008. Hail damage was simulated with a gasoline-powered string-mower at the V12 growth stage, which caused injury to leaves and defoliation. At VT, the foliar fungicides azoxystrobin and pyraclostrobin were applied to corn. Control treatments included a nontreated control and a nondamaged control. The simulated hail damage significantly (P ≤ 0.05) increased gray leaf spot severity (caused by Cercospora zeae-maydis) in 2007 but not in 2008. Simulated hail damage also significantly reduced yield compared with the nondamaged control in both 2007 and 2008. Foliar fungicides significantly reduced disease severity compared with the nontreated control in 2007 but not in 2008; however, foliar fungicides did not significantly improve yield in either the damaged or nondamaged plots compared with the nontreated controls. Results from our research trials indicated that foliar fungicides provided very little benefit to corn injured by simulated hail; thus, growers should consider factors other than hail damage when making fungicide application decisions for corn.

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Epidemiology and management of bacterial leaf spot on watermelon caused byPseudomonas syringae

Plant Disease ◽

10.1094/pdis-11-16-1628-re ◽

2017 ◽

Vol 101 (7) ◽

pp. 1222-1229 ◽

Cited By ~ 4

Author(s):

E. A. Newberry ◽

L. Ritchie ◽

B. Babu ◽

T. Sanchez ◽

K. A. Beckham ◽

...

Keyword(s):

Disease Severity ◽

Pseudomonas Syringae ◽

Leaf Spot ◽

Negative Relationship ◽

Disease Outbreaks ◽

Field Trials ◽

Multiple Regression Model ◽

Bacterial Leaf Spot ◽

Progress Curve ◽

Cool Conditions

Bacterial leaf spot of watermelon caused by Pseudomonas syringae has been an emerging disease in the southeastern United States in recent years. Disease outbreaks in Florida were widespread from 2013 to 2014 and resulted in foliar blighting at the early stages of the crop and transplant losses. We conducted a series of field trials at two locations over the course of two years to examine the chemical control options that may be effective in management of this disease, and to investigate the environmental conditions conducive for bacterial leaf spot development. Weekly applications of acibenzolar-S-methyl (ASM) foliar, ASM drip, or copper hydroxide mixed with ethylene bis-dithiocarbamate were effective in reducing the standardized area under the disease progress curve (P < 0.05). Pearson’s correlation test demonstrated a negative relationship between the average weekly temperature and disease severity (–0.77, P = 0.0002). When incorporated into a multiple regression model with the square root transformed average weekly rainfall, these two variables accounted for 71% of the variability observed in the weekly disease severity (P < 0.0001). This information should be considered when choosing the planting date for watermelon seedlings as the cool conditions often encountered early in the spring season are conducive for bacterial leaf spot development.

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