Effectiveness of Fungicides and Their Application Timing for the Management of Sorghum Foliar Anthracnose in the Mid-Atlantic United States

Sorghum anthracnose (Colletotrichum sublineola) reduces grain yield up to 50% but suggested management tactics have not yet been developed for the mid-Atlantic United States, where warm, wet conditions favor disease. Under factorial arrangement, five fungicides plus a nontreated control and four application timings were compared for foliar anthracnose control, yield, and profitability of fungicide use in grain sorghum over eight site-years in Virginia and North Carolina. Anthracnose severity was rated at the hard dough stage, and grain yield was determined at harvest. Every percent increase in disease severity resulted in yield losses of 27 to 85 kg/ha. Pyraclostrobin and pyraclostrobin plus fluxapyroxad reduced anthracnose (P < 0.01), and three applications resulted in less disease and greater yield compared with single applications (P < 0.01). However, three applications exceed the labeled maximum application for the fungicides and are not economical. Among single applications, boot or flowering timings reduced disease, and flowering applications resulted in the overall greatest yield. Results suggest that when disease onset occurs at or prior to boot, a single application of pyraclostrobin-containing fungicide at or just prior to flowering reduces anthracnose, protects yield, and increases income. However, when disease is absent or severity is low prior to flowering, fungicide application may not be profitable.

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

Plant Health Progress ◽

10.1094/php-10-21-0125-rs ◽

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.

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Does nitrogen application timing and sources influence barley grain yield?

Scientia Agraria Paranaensis ◽

10.18188/sap.v19i3.24011 ◽

2020 ◽

Vol 19 (3) ◽

pp. 264-269

Author(s):

Marcos Renan Besen ◽

Ricardo Henrique Ribeiro ◽

Felipe Bratti ◽

Jorge Luiz Locatelli ◽

Jonatas Thiago Piva

Keyword(s):

Grain Yield ◽

Plant Height ◽

N Fertilization ◽

Barley Grain ◽

Urease Inhibitor ◽

Nitrogen Application ◽

Single Application ◽

Application Timing ◽

N Source ◽

Relevant Factors

The suitable management of nitrogen (N) fertilization can increase barley grain yield, since it is the nutrient required in greater quantity. In this sense, the source and timing of nitrogen application are relevant factors. The objective was to evaluate the effects of N sources and splitting on the performance of barley. The experiment was carried out under a clayey Cambisol (550 g kg-1), in Curitibanos, Santa Catarina. Factorial randomized blocks were used: three mineral sources of N: urea (45% N); urea with urease inhibitor-NBPT (45% of N) and nitrate (30% of N), associated with two nitrogen splitting fertilization: i) split of the rate of N in two seasons: beginning of tillering and full tillering and ii) single application at full tillering. 100 kg ha-1 of N were applied. There was no interaction between the factors and there was no effect of treatments for plant height, ear length, grains per ear, ears per m² and mass of a thousand grains. Yield was influenced by the N source, where nitrate exceeded the yield from amidic sources by 16%. The splitting of N in two times did not present advantages over the single application. Urea with NBPT was not viable in relation to readily soluble forms of N, with the highest yield obtained with a nitric source.

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Optimizing chloroacetamide application timing in dicamba-resistant cotton production systems for control of glyphosate-resistant Palmer amaranth

Weed Technology ◽

10.1017/wet.2021.75 ◽

2021 ◽

pp. 1-23

Author(s):

John T. Buol ◽

Lucas X. Franca ◽

Darrin M. Dodds ◽

J. Anthony Mills ◽

Janice L. DuBien ◽

...

Keyword(s):

Yield Loss ◽

Biomass Yield ◽

Production Systems ◽

Management Program ◽

Palmer Amaranth ◽

Yield Losses ◽

Cotton Production ◽

Single Application ◽

Application Timing ◽

Late Season

A chloroacetamide herbicide by application timing factorial experiment was conducted in 2017 and 2018 in Mississippi to investigate chloroacetamide use in a dicamba-based Palmer amaranth management program in cotton production. Herbicides used were S-metolachlor or acetochlor, and application timings were preemergence, preemergence followed by (fb) early postemergence, preemergence fb late postemergence, early postemergence alone, late postemergence alone, and early postemergence fb late postemergence. Dicamba was included in all preemergence applications, and dicamba plus glyphosate was included with all postemergence applications. Differences in cotton and weed response due to chloroacetamide type were minimal, and cotton injury 14 d after LP application was less than 10% for all application timings. Late-season weed control was reduced up to 30 and 53% if chloroacetamide application occurred PRE or LP only, respectively. Late-season weed densities were minimized if multiple applications were used instead of a single application. Cotton height was reduced by up to 23% if a single application was made LP relative to other application timings. Chloroacetamide application at any timing except PRE alone minimized late season weed biomass. Yield was maximized by any treatment involving multiple applications or EP alone whereas applications PRE or LP alone resulted in up to 56 and 27% yield losses, respectively. While no yield loss was reported by delaying the first of sequential applications until EP, foregoing a PRE application is not advisable given the multiple factors that may delay timely POST applications such as inclement weather.

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Epidemiological Significance of Crown Rot in the Fruiting Field in Relation to Colletotrichum gloeosporioides Infection of Strawberry Nursery Plants

Plant Disease ◽

10.1094/pdis-06-16-0802-re ◽

2017 ◽

Vol 101 (6) ◽

pp. 907-915

Author(s):

Mahfuzur Rahman ◽

Frank J. Louws

Keyword(s):

North Carolina ◽

Colletotrichum Gloeosporioides ◽

Disease Risk ◽

Crown Rot ◽

Research Station ◽

Yield Losses ◽

Marketable Yield ◽

Percent Increase ◽

Mother Plants ◽

Fruit Harvest

Anthracnose crown rot (ACR), caused by Colletotrichum gloeosporioides, is a serious disease of strawberry (Fragaria × ananassa) in the southeastern United States, and there is a need to determine the link between nursery and fruiting-field disease risk. A 2-year study in 2007, repeated in 2008, was conducted at the North Carolina State University Horticultural Crops Research Station, Clinton, using ‘Chandler’, the most popular cultivar in North Carolina and one that is highly susceptible to ACR. Mother plants in a summer nursery were inoculated midseason with three pathogenic strains of C. gloeosporioides at an incidence level of 0, 5, 10, or 25%. Asymptomatic runner plants were selected at maturity (85 to 88 days after inoculation) from the nursery in early to mid-October from within a 0.5-m (inner) or 0.5- to 1.0-m (outer) radius around inoculated mother plants and planted into a plasticulture fruiting field system, with fruit harvest in April to June the following spring. Plants collected from the 25%-inner treatment had the greatest area under the disease progress curve (AUDPC) values, with a terminal ACR-related plant mortality of 32 and 20% by the end of fruit harvest and marketable yield losses of 30.5 and 30.2% in 2007–08 (Yr1) and 2008–09 (Yr2) seasons, respectively. All treatments increased AUDPC values compared with noninoculated treatments except the 10%-outer (O) and 5%-O treatments in Yr1 and Yr2, respectively. Marketable yield decreased 291.6 kg/ha for every percent increase in inoculum level (i.e., 0 to 25%, R2 = 0.696, P = 0.001). Levels of quiescent infection (QI) incidence (percentage of sampled leaves) assessed 25 to 28 days before digging runner plants also directly affected yield. For example, yield decreased 131.0 kg/ha for every percent increase in QI incidence in mother plants (R2 = 0.744, P = 0.001). Immersion of plants in fungicide solutions prior to planting decreased AUDPC values and improved plant stand by 7 to 11% but did not affect marketable yield compared with controls. This study provides results that can enable nursery and fruit growers to assess risk and implement mitigation measures to limit nursery plant and fruit yield losses.

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