Plant Pathology

Douglas Rouse
My research program is focused on two areas of epidemiological/ecological research. The first involves potato early dying (PED) caused primarily by the wilt fungus Verticillum dahliae. In cooperation with Dr. MacGuidwin, we are studying the role of nematodes in disease development. Our approach includes researching the influence of fungus and nematodes on crop physiology as well as identifying mechanisms of synergism. Methods being developed for this research include both molecular probes for rapid reliable assays and simulation models of crop growth as effected by Verticillum and interacting agents. We are studying the production of potatoes in mixed crop- livestock systems to determine the influence of reduced density of potato acreage on pest problems. Results to date suggest dramatically reduced need for pesticides. Alternative practices such as narrower row spacing and mechanical vine removal are being investigated for their influence on pest damage. This farming system approach has been a challenging departure from our single commodity- oriented work. influence on pest damage. This farming system approach has been a challenging departure from our single commodity- oriented work.
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Patty McManus
My research and extension programs are focused on practical problems that affect the profitability and sustainability of growing fruit crops. Wisconsin leads the nation in cranberry production; some other fruit crops grown here include apple, tart cherry, grape, strawberry, raspberry, and blueberry. The nature of our work depends largely on the current and anticipated needs of fruit growers in Wisconsin and elsewhere. We employ a variety of cultural, physiological, microscopic, and molecular techniques, and conduct research in the laboratory, greenhouse, and field.

One line of cranberry research focuses on the biology of Tobacco streak virus and determining the impact of TSV on yield components. During the course of our work on TSV, we discovered Blueberry shock virus in commercial cranberry plantings, and we are now studying the impact of this virus on cranberry production. Once we know more about how these viruses spread and how disease develops in the field, we will be better able to advise growers on managing viruses.

Ongoing cranberry research is focused on the management of fruit rot, a disease complex of at least eight fungal species. Cranberry fruit rot has become more troublesome in Wisconsin in recent years, possibly as a result of more intensive growing practices intended to increase yields. We are identifying the cultural practices and climatic variables that affect the severity of fruit rot. From these findings we will develop recommendations to help growers refine their crop management practices and minimize the impact of fruit rot.

We are collaborators on the Northern Grapes Project, a multi-state effort focused on grape and wine production in the northern US. Our role is to evaluate the so-called “cold-climate cultivars” for disease susceptibility and for sensitivity to copper- and sulfur-based fungicides. Our long-term goal is to develop economically sound integrated pest management practices for northern growers.

My extension efforts are focused on educating growers and crop consultants on: (i) identifying disease problems; (ii) managing diseases in an economically and environmentally sound manner; and (iii) managing fungicide/bactericide resistance. Extension education is conducted in large meetings of hundreds of people, in small groups, and one-on-one on the farm.
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Erin Silva
Organic crop, vegetable, and livestock production are significant contributors to Wisconsin’s agricultural landscape and economy. Second in the nation in the number of organic farms, Wisconsin continues to be a leader in organic agriculture. The University of Wisconsin Organic and Sustainable Agriculture Research and Extension program, led by Dr. Erin Silva, strives to support organic farmers through its research and outreach efforts.
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