Overview

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. Research is also being conducted to determine the impact on plant productivity of ambient ozone, which reaches concentrations that cause acute foliar injury to many crops each summer on Long Island.

Research Focus

Optimizing management of diseases affecting vegetables grown on Long Island within organic as well as conventional production systems by: investigating pathogen biology including sources, developing scouting protocols and action thresholds, and evaluating control practices, including fungicides, resistant varieties, and integration of chemical and genetic control. Examine impact on diseases of practices to improve soil health: annual compost amendments, reduced tillage, and clover living mulch. Determine impact of ambient ozone on plant productivity.

Outreach and Extension Focus

Diagnose disease problems for growers. Examine disease management practices on commercial farms. Provide growers with current information on disease management.

Additional Links

• Long Island Horticultural Research & Extension Center
• McGrath Lab and Field Program: Biology and Management of Diseases of Vegetable Crops Grown on Long Island
• McGrath Lab Web Page
• NE-1013/NE-1030 Project: "Mechanisms of Plant Responses to Ozone in the Northeastern U.S."
• Vegetable MD Online
• Link to CALS Research portal
• Link to CALS Impact statements

Honors, Awards and Appointments

• Pumpkin Production Guide (NRAES publication #123) received the Outstanding New Extension Publication Recognition in 2004 from NYS Association of County Agricultural Agents (co-author). - 2004
• Pumpkin Production Guide (NRAES publication #123) received the American Society of Horticultural Science`s award for the best extension book in the country for 2003-2004 (co-author). - 2004

Professional Activities

• What we have learned about managing Phytophthora blight. Empire State Fruit and Vegetable Expo, Syracuse, NY. 2/14/07 - 2007
• Managing cucurbit powdery mildew. 2007 New Holland Vegetable Day, New Holland, PA. 1/15/07. - 2007
• Cucurbit pest management. Workshop on Organic Insect and Disease Management for Vegetables held during the NOFA-NY Annual Conference, Syracuse, NY. 1/26/07 - 2007
• DMI Resistance Management for Powdery Mildew in Vegetables. Symposium on Triazole (DMI) Resistance, in Part 2: Case Studies and Recommendations for Various Crop Groups. Annual meeting of the American Phytopathological Society. 7/31/07 - 2007
• Practical lessons learned about fungicide resistance from cucurbit powdery mildew. Symposium on Fungicide Resistance. Annual meeting of the Northeastern Division American Phytopathological Society. Burlington, VT. 11/7/06. - 2006
• Occurrence of fungicide resistance in Podosphaera xanthii and impact on controlling cucurbit powdery mildew in New York. Cucurbitaceae '06. Ashville, NC. 9/18/06. - 2006
• Managing mildew. 2006 Mid-Atlantic Fruit and Vegetable Convention, Hershey, PA. 1/31/06. - 2006
• How should organic growers manage disease problems? Organic Vegetable and Small Fruit Meeting, Goffstown, NH. 12/6/06. - 2006
• Organic fungicides: what is available and how have they performed. Organic Vegetable and Small Fruit Meeting, Goffstown, NH. 12/6/06. - 2006
• Communicating air quality- plant effects science to the public and the user sector. Third International Conference on Plants and Environmental Pollution, Luchnow, India. 11/29/05. - 2005
• Managing cucurbit powdery mildew and fungicide resistance. Third International Cucurbit Symposium. Townsville, QLD, Australia. 9/16/05. - 2005
• History of QoI use and resistance development in cucurbit powdery mildew. Symposium on QoI Fungicide Resistance: Current Status and Management Strategies. Annual Meeting of the American Phytopathological Society. 7/31/05. - 2005

Selected Publications

• McGrath, M. T. 2004. Diseases of cucurbits and their management. In Diseases of Fruits and Vegetables, Volume I, pages 455-510. S. A. M. H. Naqvi (ed.). Kluwer Academic Publishers.
• McGrath, M. T. 2004. What are fungicides? The Plant Health Instructor. DOI: 10.1094/PHI-I-2004-0825-01. Posted in Topics in Plant Pathology, Introductory Plant Pathology, APSnet Education Center. www.apsnet.org/education/IntroPlantPath/Topics/fungicides/default.htm
• Shishkoff, N., and McGrath, M. T. 2002. In vitro evaluation of AQ10? biofungicide in combination with chemical fungicides or AddQ spray adjuvant for control of powdery mildew on squash. Plant Disease 86:915-918.
• Krupa, S., McGrath, M. T., et. al. 2001. Ambient ozone and plant health. Plant Disease 85:4-17.(Feature article).
• McGrath, M. T. 2001. Fungicide resistance in cucurbit powdery mildew: Experiences and challenges. Plant Disease 85(3):236-245.(Feature article).
• McGrath, M. T., and Shishkoff, N. 2001. Resistance to triadimefon and benomyl: dynamics and impact on control of cucurbit powdery mildew. Plant Disease 85(2):147-154.
• McGrath, M. T., and Shishkoff, N. 2000. Control of cucurbit powdery mildew with JMS Stylet-Oil. Plant Disease 84:989-993.
• McGrath, M. T., and Shishkoff, N. 1999. Evaluation of biocompatible materials for managing cucurbit powdery mildew. Crop Protection 18:471-478.
• McGrath, M. T. 1996. Increased resistance to triadimefon and to benomyl in Sphaerotheca fuliginea populations following fungicide usage over one season. Plant Disease 80:633-639.
• McGrath, M. T. 1996. Successful management of powdery mildew in pumpkin with disease threshold-based fungicide programs. Plant Disease 80:910-916.

[top]