Plant Pathology Commons^™

Detection And Characterization Of Xanthomonas Vasicola Pv. Vasculorum (Cobb 1894) Comb. Nov. Causing Bacterial Leaf Streak Of Corn In The United States, J. M. Lang, E. Ducharme, J. Ibarra Caballero, E. Luna, T. Hartman, M. Ortiz-Castro, K. A. Korus, J. Rascoe, T. A. Jackson-Ziems, K. Broders, J. E. Leach

Department of Plant Pathology: Faculty Publications

Bacterial leaf streak of corn (Zea mays) recently reached epidemic levels in three corn-growing states and has been detected in another six states in the central United States. Xanthomonas vasicola was identified as the causal agent of this disease. A multilocus sequence alignment of six housekeeping genes and comparison of average nucleotide identity from draft genome sequence were used to confirm phylogenetic relationships and classification of this bacteria relative to other X. vasicola strains. X. vasicola isolates from Nebraska and South Africa were highly virulent on corn and sugarcane and less virulent on sorghum but caused water-soaking symptoms …

Plant Disease Management, Tamra A. Jackson-Ziems, Anthony O. Adesemoye, Loren J. Giesler, Robert M. Harveson, Stephen N. Wegulo, Joshua J. Miller, James D. Harbour

Department of Plant Pathology: Faculty Publications

Fungicides are an important component of the pesticide program for some Nebraska fields. While not all fields of corn, dry bean, sorghum, soybean, sugarbeet, sunflower, and wheat will require a fungicide application, it’s critical that you know the correct product for the disease in your field when you do need it.

Identification. The first step with any disease management program is to make sure you have correctly identified the problem. Identification is critical as there are many bacterial diseases with symptoms similar to fungal diseases, and fungicides will have no activity on them. For help identifying crop diseases, visit the …

What's New In Plant Pathology, Joshua J. Miller, Anthony O. Adesemoye, Loren Giesler, Robert M. Harveson, Tamra A. Jackson-Ziems, Stephen N. Wegulo, James D. Harbour, Terra Hartman

Department of Plant Pathology: Faculty Publications

Changes to the Disease Management Section of the 2017 Guide for Weed, Disease, and Insect Management in Nebraska

Bacterial Leaf Streak of Corn—An Emerging Disease in Nebraska and First Report in the United States

Pest and Plant Diagnostic Clinic Position Change

New Products … Ethos XB … Majestene

Table 1. Foliar products for disease control that were updated in the 2017 Guide for Weed, Disease, and Insect Management in Nebraska

Table 2. Seed treatment products for disease control that were updated in the 2017 Guide for Weed, Disease, and Insect Management in Nebraska

Table 3. Biological products that were updated …

Response Of Sorghum Stalk Pathogens To Brown Midrib Plants And Soluble Phenolic Extracts From Near Isogenic Lines, Deanna L. Funnell-Harris, Patrick M. O'Neill, Scott E. Sattler, Tammy Gries, Mark A. Berhow, Jeffrey F. Pedersen

Department of Plant Pathology: Faculty Publications

Sorghum [Sorghum bicolor (L.) Moench] has drawn attention as potential feedstock for lignocellulosic biofuels production, and reducing lignin is one way to increase conversion efficiency. Little research has been previously conducted to assess the response of reduced lignin sorghum lines to the Fusarium stalk rot pathogens Fusarium verticillioides and Fusarium proliferatum and the charcoal rot pathogen, Macrophomina phaseolina. Loss of function mutations in either the Brown midrib (Bmr) 6 or 12 gene that both encode a monolignol biosynthetic enzyme in the pathway that produces subunits of the lignin polymer, results in reduced lignin content. Near-isogenic bmr6, …

Best Practices For Population Genetic Analyses, Niklaus J. Grünwald, Sydney E. Everhart, B. J. Knaus, Z. N. Kamvar

Department of Plant Pathology: Faculty Publications

Population genetic analysis is a powerful tool to understand how pathogens emerge and adapt. However, determining the genetic structure of populations requires complex knowledge on a range of subtle skills that are often not explicitly stated in book chapters or review articles on population genetics. What is a good sampling strategy? How many isolates should I sample? How do I include positive and negative controls in my molecular assays? What marker system should I use? This review will attempt to address many of these practical questions that are often not readily answered from reading books or reviews on the topic, …

Phenotypic And Genotypic Characterization Of Relevant Sclerotinia Sclerotiorum Isolates, Thomas J. Justo Miorini, Anthony G. Pannullo, T. Hornby, Robert Higgins, Sydney E. Everhart, James R. Steadman

Department of Plant Pathology: Faculty Publications

Knowledge of pathogen population structure is useful to identify isolates for screening cultivars and lines for resistance. For S. sclerotiorum, causal agent of white mold in more than 400 plant species, including common bean and soybean, breeding for resistance is particularly challenging. The objective of this study was to characterize phenotypic and genotypic variation of S. sclerotiorum isolates from soybean production areas of the U.S.A. (15), Brazil (75), and Argentina (5) to compare them with 366 isolates from dry bean characterized previously (Everhart et al., 2016).

Best Practices For Population Genetic Analyses, Niklaus J. Grünwald, Sydney E. Everhart, B. J. Knaus, Zhian N. Kamvar

Department of Plant Pathology: Faculty Publications

Population genetic analysis is a powerful tool to understand how pathogens emerge and adapt. However, determining the genetic structure of populations requires complex knowledge on a range of subtle skills that are often not explicitly stated in book chapters or review articles on population genetics. What is a good sampling strategy? How many isolates should I sample? How do I include positive and negative controls in my molecular assays? What marker system should I use? This review will attempt to address many of these practical questions that are often not readily answered from reading books or reviews on the topic, …

Control Of White Mold Of Dry Bean And Residual Activity Of Fungicides Applied By Chemigation, Thomas J.J. Miorini, Carlos G. Raetano, Sydney E. Everhart

Department of Plant Pathology: Faculty Publications

Sclerotinia sclerotiorum is a necrotrophic fungal pathogen that causes white mold of dry bean (Phaseolus vulgaris L.). Chemigation with fungicides is used for disease control, but effectiveness of this application method and impact of irrigation level on residual fungicide activity in the plant over time under field conditions has not been well characterized. To assess the best method of application and fungicide for disease control, we conducted field studies in three field sites in São Paulo State in Brazil. Contact fungicide, fluazinam, was applied via center pivot at three irrigation levels (2.5, 5.1, 10.1 mm) at the Itaí field …

Glucose-Abl1-Tor Signaling Modulates Cell Cycle Tuning To Control Terminal Appressorial Cell Differentiation, Margarita Marroquin-Guzman, Guangchao Sun, Richard Wilson

Department of Plant Pathology: Faculty Publications

The conserved target of rapamycin (TOR) pathway integrates growth and development with available nutrients, but how cellular glucose controls TOR function and signaling is poorly understood. Here, we provide functional evidence from the devastating rice blast fungus Magnaporthe oryzae that glucose can mediate TOR activity via the product of a novel carbon- responsive gene, ABL1, in order to tune cell cycle progression during infection-related development. Under nutrient-free conditions, wild type (WT) M. oryzae strains form terminal plant-infecting cells (appressoria) at the tips of germ tubes emerging from three-celled spores (conidia). WT appressorial development is accompanied by one round …

Genes Linked To Production Of Secondary Metabolites In Talaromyces Atroroseus Revealed Using Crispr-Cas9, Maria Lund Nielsen, Thomas Isbrandt, Kasper Bøwig Rasmussen, Ulf Thrane, Jakob Blæsbjerg Hoof, Thomas Ostenfeld Larsen, Uffe Hasbro Mortensen

Department of Plant Pathology: Faculty Publications

The full potential of fungal secondary metabolism has until recently been impeded by the lack of universal genetic tools for most species. However, the emergence of several CRISPR-Cas9-based genome editing systems adapted for several genera of filamentous fungi have now opened the doors for future efforts in discovery of novel natural products and elucidation and engineering of their biosynthetic pathways in fungi where no genetic tools are in place. So far, most studies have focused on demonstrating the performance of CRISPR-Cas9 in various fungal model species, and recently we presented a versatile CRISPR-Cas9 system that can be successfully applied in …

Muti Site Screening Identifies And Verifies Levels Of Resistance To White Mold In Common Bean In 2016, Robert Higgins, James R. Steadman

Department of Plant Pathology: Faculty Publications

The development of common bean cultivars with partial resistance and/ or avoidance to white mold (WM) caused by Sclerotinia sclerotiorum would benefit producers by reducing yield loss and reducing input costs for fungicides. Our main objective in this study is to identify bean germplasm supplied by bean breeders from across the USA and Belgium with levels of partial resistance to WM. Breeders sent seed of 9 bean lines for field testing and 25 bean lines for greenhouse testing with putative sources of resistance to our laboratory. The seeds were divided in equal amounts for field (400g/line) and/or greenhouse (25 seeds/ …

Wheat Streak Mosaic Virus Coat Protein Is A Host-Specific Long-Distance Transport Determinant In Oat, Satyanarayana Tatineni

Department of Plant Pathology: Faculty Publications

Viral determinants involved in systemic infection of hosts by monocot-infecting plant viruses are poorly understood. Wheat streak mosaic virus (WSMV, genus Tritimovirus, family Potyviridae) exclusively infects monocotyledonous crops such as wheat, oat, barley, maize, triticale, and rye. Previously, we reported that WSMV CP amino acids 36–84 are expendable for systemic infection of wheat, maize, barley and rye. In this study, the role of coat protein (CP) in systemic infection of oat by WSMV was examined by using a series of viable deletion mutants. WSMV bearing deletions within or encompassing all of amino acids 36–57 efficiently infected oat, indicating that …

Understanding Fungicide Resistance, Tamra A. Jackson-Ziems, Loren J. Giesler, Anthony O. Adesemoye, Robert M. Harveson, Stephen N. Wegulo

Department of Plant Pathology: Faculty Publications

Fungicide resistance has developed in some diseases of row crops as well as specialty crops. This implies that fungicide applications to control such diseases may no longer be effective. Scientific studies have shown that fungicide resistance develops through natural selection of a mutant strain of a pathogen in a population that is resistant to fungicides. Resistance is very difficult to eliminate but can be delayed through appropriate management practices. The availability of inexpensive options with single mode of action products being available makes this an important issue so we do not repeat what was done in weed management.

Introduction

Frogeye …

Population Structure And Phenotypic Variation Of Sclerotinia Sclerotiorum From Dry Bean (Phaseolus Vulgaris) In The United States, Zhian N. Kamvar, Bimal Sajeewa Amaradasa, Rachana Jhala, Serena Mccoy, James R. Steadman, Sydney Everhart

Department of Plant Pathology: Faculty Publications

The ascomycete pathogen Sclerotinia sclerotiorum is a necrotrophic pathogen on over 400 known host plants, and is the causal agent of white mold on dry bean. Currently, there are no known cultivars of dry bean with complete resistance to white mold. For more than 20 years, bean breeders have been using white mold screening nurseries (wmn) with natural populations of S. sclerotiorum to screen new cultivars for resistance. It is thus important to know if the genetic diversity in populations of S. sclerotiorum within these nurseries (a) reflect the genetic diversity of the populations in the surrounding region and (b) …

The Coat Protein And Nia Protease Of Two Potyviridae Family Members Independently Confer Superinfection Exclusion, Satyanarayana Tatineni, Roy French

Department of Plant Pathology: Faculty Publications

Superinfection exclusion (SIE) is an antagonistic virus-virus interaction whereby initial infection by one virus prevents subsequent infection by closely related viruses. Although SIE has been described in diverse viruses infecting plants, humans, and animals, its mechanisms, including involvement of specific viral determinants, are just beginning to be elucidated. In this study, SIE determinants encoded by two economically important wheat viruses, Wheat streak mosaic virus (WSMV; genus Tritimovirus, family Potyviridae) and Triticum mosaic virus (TriMV; genus Poacevirus, family Potyviridae), were identified in gain-of-function experiments that used heterologous viruses to express individual virus-encoded proteins in wheat. Wheat plants infected …

Corn Yield Loss Estimates Due To Diseases In The United States And Ontario, Canada From 2012 To 2015, Daren S. Mueller, Kiersten A. Wise, Adam J. Sisson, Tom W. Allen, Gary C. Bergstrom, D. Bruce Bosley, Carl A. Bradley, Kirk D. Broders, Emmanuel Byamukama, Martin I. Chilvers, Alyssa Collins, Travis R. Faske, Andrew J. Friskop, Ron W. Heiniger, Clayton A. Hollier, David C. Hooker, Tom Isakeit, Tamra A. Jackson-Ziems, Douglas J. Jardine, Heather M. Kelly, Kasia Kinzer, Steve R. Koenning, Dean K. Malvick, Marcia Mcmullen, Ron F. Meyer, Pierce A. Paul, Alison E. Robertson, Gregory W. Roth, Damon L. Smith, Connie A. Tande, Albert U. Tenuta, Paul Vincelli, Fred Warner

Department of Plant Pathology: Faculty Publications

Annual decreases in corn yield caused by diseases were estimated by surveying members of the Corn Disease Working Group in 22 corn-producing states in the United States and in Ontario, Canada, from 2012 through 2015. Estimated loss from each disease varied greatly by state and year. In general, foliar diseases such as northern corn leaf blight, gray leaf spot, and Goss’s wilt commonly caused the largest estimated yield loss in the northern United States and Ontario during nondrought years. Fusarium stalk rot and plant-parasitic nematodes caused the most estimated loss in the southern-most United States. The estimated mean economic loss …

Mapping Quantitative Trait Loci For Resistance To Goss’S Bacterial Wilt And Leaf Blight In North American Maize By Joint Linkage Analysis, Amritpal Singh, Aaron P. Andersen, Tamra A. Jackson-Ziems, Aaron J. Lorenz

Department of Plant Pathology: Faculty Publications

Goss’s wilt and leaf blight is a bacterial disease of maize (Zea mays L.) caused by the Gram-positive bacterium Clavibacter michiganensis subsp. nebraskensis. Goss’s wilt has reemerged as an important disease in the western United States and is spreading to other areas. Although the reasons for this reemergence are not completely known, it is important to understand the genetic basis of resistance to Goss’s wilt. The objective of this study was to map the quantitative trait loci (QTL) underlying resistance to Goss’s wilt. To achieve this objective, joint linkage and linkage mapping in 3 of the 25 nested …

Bacterial Leaf Streak Of Corn Confirmed In Nebraska, Other Corn Belt States August 26, 2016, Tamra Jackson-Ziems, Kevin A. Korus, Tony Adesemoye, Julie Van Meter

Department of Plant Pathology: Faculty Publications

Bacterial leaf streak disease of corn, caused by Xanthomonas vasicola pv. vasculorum, has now been confirmed in Nebraska, as well as in Colorado, Illinois, Iowa, and Kansas. The disease had not been previously identified in the U.S., but had been reported on corn in South Africa. Surveys are currently underway across the Corn Belt to identify the disease distribution. Initial observations and survey results suggest that it may be widely distributed throughout the Corn Belt. Unusual symptoms were first reported on corn samples received by the University of Nebraska Plant and Pest Diagnostic Clinic. Over the last two years, the …

Validation Of Reference Genes For Robust Qrt-Pcr Gene Expression Analysis In The Rice Blast Fungus Magnaporthe Oryzae, Sarena Che Omar, Michael A. Bentley, Giulia Morieri, Gail M. Preston, Sarah J. Gurr, Richard Wilson (Editor)

Department of Plant Pathology: Faculty Publications

The rice blast fungus causes significant annual harvest losses. It also serves as a genetically- tractable model to study fungal ingress. Whilst pathogenicity determinants have been unmasked and changes in global gene expression described, we know little about Magnaporthe oryzae cell wall remodelling. Our interests, in wall remodelling genes expressed during infection, vegetative growth and under exogenous wall stress, demand robust choice of reference genes for quantitative Real Time-PCR (qRT-PCR) data normalisation. We describe the expression stability of nine candidate reference genes profiled by qRT-PCR with cDNAs derived during asexual germling development, from sexual stage perithecia and from vegetative mycelium …

Antiviral Rna Silencing Suppression Activity Of Tomato Spotted Wilt Virus Nss Protein, Tania Ocampo Ocampo, Sergio M. Gabriel Peralta, Nicole Bacheller, Stella Uiterwaal, Aaron Knapp, Alanna Hennen, Daniel Leobardo Ochoa-Martínez, Hernan Garcia-Ruiz

Department of Plant Pathology: Faculty Publications

In addition to regulating gene expression, RNA silencing is an essential antiviral defense system in plants. Triggered by double-stranded RNA, silencing results in degradation or translational repression of target transcripts. Viruses are inducers and targets of RNA silencing. To condition susceptibility, most plant viruses encode silencing suppressors that interfere with this process, such as the Tomato spotted wilt virus (TSWV) NSs protein. The mechanism by which NSs suppresses RNA silencing and its role in viral infection and movement remain to be determined. We cloned NSs from the Hawaii isolate of TSWV and using two independent assays show for the first …

Description Of Mesocriconema Ericaceum N. Sp. (Nematoda: Criconematidae) And Notes On Other Nematode Species Discovered In An Ericaceous Heath Bald Community In Great Smoky Mountains National Park, Usa, Thomas O. Powers, Peter Mullin, Rebecca Higgins, Timothy Harris, Kirsten S. Powers

Department of Plant Pathology: Faculty Publications

A new species of Mesocriconema and a unique assemblage of plant-parasitic nematodes was discovered in a heath bald atop Brushy Mountain in Great Smoky Mountains National Park. Mesocriconema ericaceum n. sp., a species with males, superficially resembles M. xenoplax. DNA barcoding with the mitochondrial COI gene provided evidence of the new species as a distinct lineage. SEM revealed significant variability in arrangement of labial submedian lobes, plates, and anterior and posterior annuli. Three other nematodes in the family Criconematidae were characterized from the heath bald. Ogma seymouri, when analyzed by statistical parsimony, established connections with isolates from north-eastern Atlantic …

Microbe-Id: An Open Source Toolbox For Microbial Genotyping And Species Identification, Javier F. Tabima, Sydney E. Everhart, Meredith M. Larsen, Alexaandra J. Weisberg, Zhian N. Kamvar, Mathew A. Tancos, Christine D. Smart, Jeff H. Chang, Niklaus J. Grünwald

Department of Plant Pathology: Faculty Publications

Development of tools to identify species, genotypes, or novel strains of invasive organisms is critical for monitoring emergence and implementing rapid response measures. Molecular markers, although critical to identifying species or genotypes, require bioinformatic tools for analysis. However, user-friendly analytical tools for fast identification are not readily available. To address this need, we created a web-based set of applications called Microbe-ID that allow for customizing a toolbox for rapid species identification and strain genotyping using any genetic markers of choice. Two components of Microbe-ID, named Sequence-ID and Genotype-ID, implement species and genotype identification, respectively. Sequence-ID allows identification of species by …

First Report Of Pythium Ultimum, P. Irregulare, Rhizoctonia Solani Ag4, And Fusarium Proliferatum From Arrowleaf Clover (Trifolium Vesiculosum): A Disease Complex, I. J. Pemberton, G. R. Smith, G. L. Philley, F. M. Rouquette, G. Y. Yuen

Department of Plant Pathology: Faculty Publications

Poor stand establishment, failure to recover after grazing, and premature plant death have reduced the utilization of arrowleaf clover (Trifolium vesiculosum Savi) as a forage crop in the southeastern United States in recent years. Clover plants collected from poor stands in east Texas pastures during the 1995 to 1996 and 1996 to 1997 seasons first exhibited root disease symptoms as young seedlings in the fall. Symptoms consisted of one or more of the following: tan discoloration of lateral roots and taproot; root pruning; and small, tan, sunken lesions on the taproot and crown. Many Rhizobium nodules were brown and …

Dry Edible Bean Disease Diagnostic Series, Samuel G. Markell, Robert M. Harveson, Julie Pasche

Department of Plant Pathology: Faculty Publications

Root Diseases

Fusarium root rot...................................PP1820-1

Pythium diseases..................................PP1820-2

Rhizoctonia root rot...............................PP1820-3

Soybean cyst nematode (SCN).............PP1820-4

Soybean cyst nematode sampling.........PP1820-5

Stem and Wilt Diseases

Bacterial wilt..........................................PP1820-6

Fusarium yellows (wilt)..........................PP1820-7

Stem rot.................................................PP1820-8

White mold.............................................PP1820-9

Foliar Diseases

Anthracnose........................................PP1820-10

Bacterial brown spot............................PP1820-11

Bean common mosaic virus................PP1820-12

Common bean rust..............................PP1820-13

Common bacterial blight .....................PP1820-14

Halo blight............................................PP1820-15

Cryptic Species: A Leitmotif Of Contemporary Mycology Has Challenges And Benefits For Plant Pathologists, Frank M. Dugan, Sydney Everhart

Department of Plant Pathology: Faculty Publications

Multiple traditional species names for plant pathogenic fungi have been supplemented with new names that delimit formerly cryptic species. In separate instances, isolates within a species are clearly differentiated by both phylogeny and distinctive pathogenic traits and are assigned sub-specific designations. These new species names and the sub-specific designations are both cases of cryptic species that are, in some instances, relevant and/or critical for plant disease management. Here we provide examples of such instances in which newly described taxa differ from the original (“parent”) in phenotypic traits of importance to plant disease management: host range, fungicide sensitivity, environmental niche, metabolite …

Foliar Fungicide Comparison For Southern Rust Management, Stay Green, Push Lodging, And Yield In Nebraska, 2015, J. D. Harbour, T. A. Jackson-Ziems

Department of Plant Pathology: Faculty Publications

The objective of the trial was to compare foliar fungicides for southern rust (SR) efficacy. Irrigated corn was grown based on Nebraska Extension irrigation recommendations at the South Central Ag Lab near Clay Center, NE. Soils were a silt loam with 6.7 pH and 1.8 % OM and the previous crop was soybean. Reduced tillage was performed to the field prior to planting. Corn (DKC 65-79 RIB, tolerant to gray leaf spot (GLS)) was planted at approximately 34,000 seed/A on 26 May. Eight treatments were arranged in a randomized complete block design with six replications. . . . Stalk lodging …

Fungicide Application Timing With Effects On Grey Leaf Spot And Southern Rust In Nebraska Field Corn, 2015, J. D. Harbour, T. A. Jackson-Ziems

Department of Plant Pathology: Faculty Publications

The objective of the trial was to compare foliar fungicides applied to three growth stages of corn for grey leaf spot (GLS) and southern rust (SR) efficacy. Irrigated corn was grown based on Nebraska Extension irrigation recommendations at the South Central Ag Lab near Clay Center, NE. Soils were a silt loam with 6.7 pH and 1.8% OM and the previous crop was soybean. Reduced tillage was performed to the field prior to planting. Corn (DKC 65-79 RIB, tolerant to gray leaf spot) was planted at approximately 34,000 seed/A on 26 May. Eight treatments were arranged in a randomized complete …

Diseases Caused By Parasitic Nematodes, T. A. Jackson-Ziems

Department of Plant Pathology: Faculty Publications

Some plant-parasitic nematodes occur in every [sunflower] production field. Nematode populations likely include multiple species, although not all species cause notable disease. Symptoms depend on the species, the population density, and the crop's interaction with environmental factors. Several nematode species are known to cause disease in sunflower, although little research has focused on their impact or management in the crop. The highest population densities of plant-parasitic nematodes often occur in isolated areas that are randomly distributed in fields, as do the most severe plant symptoms. Symptoms are not necessarily diagnostic for nematodes, and the problem may be misdiagnosed. The most …

Response Of Sweet Sorghum Lines To Stalk Pathogens Fusarium Thapsinum And Nacrophomina Phaseolina, Deanna L. Funnell-Harris, Patrick M. O'Neill, Scott E. Sattler, Melinda K. Yerka

Department of Plant Pathology: Faculty Publications

Sweet sorghum [Sorghum bicolor (L.) Moench] has potential for bioenergy. Itis adapted to a variety of U.S. locations and the extracted juice can be directly fermented into ethanol. However, little research on fungal stalk rots, diseases that pose serious constraints for yield and quality of juice and biomass, has been reported. A greenhouse bioassay was designed to assess charcoal rot (Macrophomina phaseolina) and Fusarium stalk rot (Fusarium thapsinum) in plants at maturity, the developmental stage at which these diseases are manifested. Multiple plantings of a susceptible grain line, RTx430, were used as a control for variation …

Foliar Fungicide Comparison For Southern Rust Management, Stay Green On Specific Leaves, And Yield In Nebraska, 2015, J. D. Harbour, T. A. Jackson-Ziems

Department of Plant Pathology: Faculty Publications

The objective of the trial was to compare foliar fungicides for southern rust (SR) efficacy. Irrigated corn was grown based on Nebraska Extension irrigation recommendations at the South Central Ag Lab near Clay Center, NE. Soils were a silt loam with 6.7 pH and 1.8 % OM and the previous crop was soybean. Reduced tillage was performed to the field prior to planting. Corn (DKC 65-79 RIB, tolerant to gray leaf spot (GLS)) was planted at approximately 34,000 seed/A on 26 May. Five treatments were arranged in a randomized complete block design with six replications. . . . Phytotoxicity was …