Department Chair, Professor, and Extension Specialist
689 Russell Labs
1630 Linden Dr
Madison, WI 53706
Ph.D. Plant Pathology – Michigan State University
M.S. Plant Pathology – Purdue University
My research program investigates the ecology of fungus and fungus-like plant pathogens for enhanced and integrated disease management. Specifically, we investigate Phytophthora species pathogenic on potato and vegetable crops in field and storage. My program conducts research on P. infestans, P. capsici, and P. erythroseptica to determine pathogen genotypes/races/clonal lineages, mating types, host range, virulence, survivability, and resistance to commonly utilized fungicides. Improved understanding of pathogen characters has promptly influenced statewide recommendations for Phytophthora disease management in Wisconsin production of potatoes and vegetables.
A second program emphasis is on species distribution and occurrence of pathogenic Alternaria affecting potato. Preliminary studies confirmed the presence of A. alternata in late season epidemics of early blight in northern Wisconsin. Speciation of Alternaria throughout the production season at several regions of concentrated potato production in Wisconsin is being undertaken to further characterize the pathogen profile. Additionally, sub-populations of Alternaria spp. collected from potatoes were partially resistant to the commonly-used fungicide active ingredient, azoxystrobin. Mechanisms of fungicide resistance can differ between species. As such, species determination may aid in regional or field-level tailoring of fungicide programs for enhanced disease control. Early blight, caused by A. solani, is present every year in Wisconsin and can, if unmanaged, cause significant yield loss and reduction in tuber quality. The importance and incidence of brown spot, caused by A. alternata, is poorly understood in Wisconsin at this time. Our research addresses efficacy of novel fungicides and fungicide programs for more immediate application and support of grower needs, as well exploring pathogen ecological factors which may influence longer term disease management solutions.
A final area of research emphasis is the investigation of component inputs and development of integrated disease management programming in potato systems to reduce reliance upon soil fumigation in managing key soilborne diseases. Our research approaches have included evaluation of disease control with reduced rates, alternative formulations, and in-line versus broadcast applications of soil fumigants such as chloropicrin and metam sodium to reduce quantity of soil-applied chemical. Preliminary work suggests similar efficacy of some in-line-applied fumigants compared to broad-cast fumigants, offering a reduction in chemical use, and off-target and negative environmental and human health effects. At-plant applications of nematicidal and fungicidal materials, potato vine removal, crop rotations, and cover crops have also been investigated with some positive preliminary results. Soilborne diseases of potato such as potato early dying and common scab are especially challenging to manage and our research in this area of fumigation alternatives has been of great interest in regional industry and in academic circles.
As the UW-Extension Potato and Vegetable Pathologist, my program supports vegetable growers by providing research-based recommendations for controlling diseases during production and in storage. My research program directly feeds into my extension work.
Along with a team of UW vegetable production scientists across departments, I extend knowledge through grower educational meetings, through our UW Vegetable Crop Updates Newsletter distributed online and by email, through direct email or phone consultations, and through one-on-one visits and discussion. The connections between researchers and growers are strong in WI, with growers providing extensive intellectual and farm resources in contribution to world-class applied and basic agricultural research.