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Margaret McGrath

Margaret McGrath

Associate Professor

Long Island Horticultural Research & Extension Center, Riverhead, NY 11901-1098
(631) 727-3595

The goal of my applied research/extension program is to improve the management of important diseases of vegetable crops grown on Long Island with both conventional and organic production systems. Typically these diseases have been important elsewhere in the northeastern United States. To reach this goal, I am conducting research to increase our understanding of these diseases and to develop effective components for integrated pest management (IPM) programs. Specifically, I identify the sources of the disease-causing organisms, determine how these organisms survive between crops, develop scouting protocols and action thresholds for timing the initiation of fungicide applications after disease detection, investigate factors that favor disease development and use this information for timing fungicide applications, and evaluate new control tactics. Fungicide resistance can be an important consideration in managing diseases, therefore effort is devoted to studying its occurrence, its impact on disease control and its management. Diseases studied include powdery mildew, bacterial wilt and Phytophthora blight of cucurbit crops, white rust of spinach, bacterial leaf spot of pepper, early blight and powdery mildew of tomato, and black rot of crucifers. Management practices for improving soil health are being examined for their impact on plant diseases.

Outreach and Extension Focus

Applied research is conducted on managing vegetable diseases during summer. Farms are visited to determine disease occurrence and to diagnosis problems. Disease samples are also submitted to the laboratory by growers and IPM scouts. Field Days and Twilight Meetings are hosted annually to permit growers an opportunity to see research results for themselves. Findings are shared with growers predominantly in the northeastern US through newsletter articles, web postings, and presentations at grower meetings during winter. Growers are also provided with general information on diseases and their management, especially new developments. Materials for outside NY often need to be adjusted due to differences in fungicide registration. Phone calls and e-mail requests for information from growers and extension specialists are answered throughout the year. Content of the Cornell Integrated Crop and Pest Management Guidelines for Vegetables is updated each fall with other Cornell University extension faculty. When needed, requests are prepared and submitted for emergency registration of new fungicides and for fungicide label amendments (eg 2(ee) requests for adding diseases) for NY. Comments from growers and other stakeholders and survey results are the primary means used to assess program success. Two-hour session on “Plant diseases and their management” is presented each year for the annual Master Gardener Training Program.

Awards and Honors

  • 2016 Excellence in IPM Award (2016) New York State Integrated Pest Management Program
  • 2014 IR-4 SOAR Award for excellent Service, Outreach, Altruism, and Research efforts (2014) IR-4

Selected Publications

Journal Publications

Presentations and Activities

  • Biofumigation and Reduced Tillage as Components of Successful Integrated Management Programs for Phytophthora capsici. 4th International Phytophthora capsici Conference. December 2013. University of Florida. Duck Key, FL USA.
  • Cross Resistance Among Some SDHI Fungicides Documented in Podosphaera xanthii, the Cucurbit Powdery Mildew Pathogen. Northeastern Division American Phytopathological Society Annual Meeting. October 2013. Northeastern Division American Phytopathological Society. Southbury, CT USA.
  • Efficacy of Fungicides with Resistance Risk for Cucurbit Powdery Mildew and Fungicide Sensitivity of Podosphaera xanthii in New York. American Phytopathological Society Annual Meeting. August 2013. American Phytopathological Society. Austin, TX USA.
  • An Overview of Fungicides and Resistance Development in Vegetable Crops in the USA. 10th International Congress of Plant Pathology (ICPP 2013). August 2013. International Congress of Plant Pathology. Beijing, China.
  • Evaluating Biopesticides for Managing Diseases in Vegetable and Herb Crops. 10th International Congress of Plant Pathology (ICPP 2013). August 2013. International Congress of Plant Pathology. Beijing, China.
  • Recent Occurrences of Late Blight on Tomatoes in the Northeastern USA. Joint meeting of the 4th International Symposium on Tomato diseases and the 28th U.S Annual Tomato Disease Workshop. June 2013. Department of Plant Pathology/NFREC, University of Florida, the International Society for Horticultural Science, and the U.S Tomato Diseases Research Group. Orlando, FL USA.
  • Occurrence of late blight on Long Island, NY, in 2012 and evaluation of resistant tomatoes. 27th annual Tomato Disease Workshop. October 2012. Wooster, OH.
  • Phytophthora infestans transmitted to seedlings growing from tomato fruit rotted by late blight but not their seed. American Phytopathological Society Annual Meeting. August 2012. American Phytopathological Society. Providence, RI.
  • eOrganic: The eXtension CoP for organic agriculture. 7th International IPM Symposium. March 2012. Integrated Pest Management. Memphis, TN.
  • Fungicide resistance: Current situation and management challenges. 7th International IPM Symposium. March 2012. Integrated Pest Management. Memphis, TN.