Effect of Fungicide and Timing of Application on Management of Phoma Black Stem of Cultivated Sunflowers in the United States.

Phoma black stem (PBS), caused by Boerema (teleomorph Frezzi), is the most common stem disease of sunflower ( L.) in the northern Great Plains region of the United States. However, the impact of PBS on sunflower yield in the United States is unclear, and a near complete absence of information on the impact of fungicides on disease management exists.

Management of Soybean Cyst Nematode and Sudden Death Syndrome with Nematode-Protectant Seed Treatments Across Multiple Environments in Soybean.

As soybean () production continues to expand in the United States and Canada, so do pathogens and pests that directly threaten soybean yield potential and economic returns for farmers. One such pathogen is the soybean cyst nematode (SCN; ). SCN has traditionally been managed using SCN-resistant cultivars and rotation with nonhost crops, but the interaction of SCN with sudden death syndrome (SDS; caused by ) in the field makes management more difficult.

Ascochyta blight in North Dakota field pea: the pathogen complex and its fungicide sensitivity.

Worldwide, Ascochyta blight is caused by a complex of host-specific fungal pathogens, including , , and . The application of foliar fungicides is often necessary for disease management, but a better understanding of pathogen prevalence, aggressiveness, and fungicide sensitivity is needed to optimize control. Leaf and stem samples were obtained from 56 field pea production fields in 14 counties in North Dakota from 2017 to 2020 and isolates were collected from lesions characteristic of Ascochyta blight.

Foliar Fungicides Containing FRAC 11 Mitigate Phomopsis Stem Canker in Sunflower ().

Phomopsis stem canker reduces yield of sunflower ( L.) up to or exceeding 40%; however, management recommendations have not been developed for U.S.

Multiple Species of Asteraceae Plants Are Susceptible to Root Infection by the Necrotrophic Fungal Pathogen .

The necrotrophic fungal pathogen can cause disease on numerous plant species, including many important crops. Most -incited diseases of crop plants are initiated by airborne ascospores produced when fungal sclerotia germinate to form spore-bearing apothecia. However, basal stalk rot of sunflower occurs when sclerotia germinate to form mycelia within the soil, which subsequently invade sunflower roots.

A Greenhouse Method to Evaluate Sunflower Quantitative Resistance to Basal Stalk Rot Caused by .

Resistance of sunflower to basal stalk rot (BSR) caused by the fungus is quantitative, controlled by multiple genes contributing small effects. Consequently, artificial inoculation procedures allowing sufficient throughput and resolution of resistance are needed to identify highly resistant sunflower germplasm resources and to map loci contributing to resistance. The objective of this study was to develop a greenhouse-based method for evaluating sunflower quantitative resistance to BSR that would be simple, space- and time-efficient, high throughput, high resolution, and correlated with field observations.

Determination of Virulence Phenotypes of in the United States.

Downy mildew, caused by (Farl.) Berl. and de Toni, is an economically important disease in cultivated sunflowers, L.

Developing Public-Private Partnerships in Plant Pathology Extension: Case Studies and Opportunities in the United States.

Public-private partnerships (PPPs) can be an effective and advantageous way to accomplish extension and outreach objectives in plant pathology. The greatest opportunities for extension-focused PPPs may be in response to large-scale or emerging disease management concerns or in addressing complex issues that impact agriculture, such as climate change, digital technology, and public perception of science. The most fertile ground for forming PPPs is where the needs and strengths of the public and private sectors are complementary.

Quantitative PCR Assays Developed for and for Phomopsis Stem Canker Diagnosis and Germplasm Screening in Sunflower ().

Phomopsis stem canker of sunflower is caused by two fungal pathogens, and , in the United States. In this study, two quantitative PCR (qPCR) assays were developed to detect and quantify and in sunflower. The two assays differentiated the two fungi from each other, other species of the genus , and pathogens, and they have high efficiency (>90%).

Evaluation of Oxathiapiprolin for the Management of Sunflower Downy Mildew.

Downy mildew is a yield-limiting disease of sunflower, caused by the pathogen . Zoospore infection of root tissue shortly after planting results in systemic infection, causing postemergence damping off or severe stunting and head sterility. Although fungicide-applied seed treatments can be an effective management tool, the pathogen is resistant to phenylamide fungicides in many growing regions, and other available fungicides have limited efficacy.

Oomycete Species Associated with Soybean Seedlings in North America-Part II: Diversity and Ecology in Relation to Environmental and Edaphic Factors.

Soybean (Glycine max (L.) Merr.) is produced across a vast swath of North America, with the greatest concentration in the Midwest.

Oomycete Species Associated with Soybean Seedlings in North America-Part I: Identification and Pathogenicity Characterization.

Oomycete pathogens are commonly associated with soybean root rot and have been estimated to reduce soybean yields in the United States by 1.5 million tons on an annual basis. Limited information exists regarding the frequency and diversity of oomycete species across the major soybean-producing regions in North America.

Phenotypic Diversity of Puccinia helianthi (Sunflower Rust) in the United States from 2011 and 2012.

Puccinia helianthi, causal agent of sunflower rust, is a macrocyclic and autoecious pathogen. Widespread sexual reproduction of P. helianthi was documented in North Dakota and Nebraska for the first time in 2008 and has since frequently occurred.

Effect of Fungicide and Timing of Application on Management of Sunflower Rust.

Sunflower rust is an important yield-limiting disease in sunflower production in the Great Plains of the United States. Rust severity and incidence have increased between 2002 and 2011, and genetic resistance is limited in most commercial hybrids, particularly the high-value confectionary market type. Although fungicides are available for rust management in the United States, management recommendations are insufficient.

Phomopsis Stem Canker: A Reemerging Threat to Sunflower (Helianthus annuus) in the United States.

Phomopsis stem canker causes yield reductions on sunflower (Helianthus annuus L.) on several continents, including Australia, Europe, and North America. In the United States, Phomopsis stem canker incidence has increased 16-fold in the Northern Great Plains between 2001 and 2012.

Gene cloning using degenerate primers and genome walking.

Gene cloning is the first step of targeted gene replacement for functional studies, discovery of gene alleles, and gene expression among other applications. In this chapter, we will describe a cloning technique suitable for fungal species where the genomic information and sequences available are limited. This strategy involves obtaining protein sequences of the gene of interest from various organisms to identify at least two conserved regions.

A resource for the in silico identification of fungal polyketide synthases from predicted fungal proteomes.

The goal of this study was to develop a tool specifically designed to identify iterative polyketide synthases (iPKSs) from predicted fungal proteomes. A fungi-based PKS prediction model, specifically for fungal iPKSs, was developed using profile hidden Markov models (pHMMs) based on two essential iPKS domains, the β-ketoacyl synthase (KS) domain and acyltransferase (AT) domain, derived from fungal iPKSs. This fungi-based PKS prediction model was initially tested on the well-annotated proteome of Fusarium graminearum, identifying 15 iPKSs that matched previous predictions and gene disruption studies.