Assistant Professor of Plant Pathology

Purdue University
Botany and Plant Pathology, Lilly Hall
915 West State Street
West Lafayette, IN 47907-2054

Office:  LILY 1-321
Phone:  (765) 494-4628
FAX:      (765) 494-0363
E-mail:   

Area: Ornamental and Fruit Diseases - Extension and research activities related to disease management of landscape ornamentals; nursery and greenhouse crops, and fruit crops.

Education

Ph.D., Texas A&M University, Plant Pathology

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Research Interests

Research and Extension - Apples

The goal of our research is to develop environmentally sound disease management strategies that are economically feasible for Indiana growers producing apples. To do so, we are developing two web-based programs: 1) a program to assist growers in developing effective fungicide rotations and 2) a forecasting tool for the major diseases that infect apples. Our research effort is directly tied to our extension work, and focuses on the identification and management of fungicide resistance. To that end, we are currently surveying Indiana orchards to evaluate the incidence of fungicide resistance in Venturia inaequalis, the fungus that causes apple scab, and Glomerella cingulata, the causal agent of bitter rot. An effective fungicide rotation, coupled with good forecasting tools reduces chemical inputs, and minimizes the likelihood of fungicide resistance developing.

Apple scab is one of the most serious diseases of apple and ornamental flowering crabapple, and affects both leaves and fruit. In commercial apple production, foliar infection by the apple scab pathogen results in defoliation that leads to a loss of apple quality, and impacts winter-hardiness. Fruit infections result in blemished and deformed fruit that cannot be sold. In commercial apple production, this disease is primarily managed through the use of fungicides. However, fungicide resistance is an emerging problem. We are currently surveying the Venturia inaequalis population for the presence of fungicide resistance.

Recent restrictions in fungicide registrations have resulted in the development of management issues for diseases that were previously minor problems. Bitter rot is a common orchard disease, but has been increasing in incidence and severity across the Midwest due to changes in pesticide labeling. We are currently collecting isolates from Indiana orchards to determine if fungicide resistance, or changes in fungicide use has resulted in the increase of this problem.

Additional research involves fungicide trials for control of Phytophthora collar rot in commercial apples, an organic fungicide study, and the efficacy of fungicides registered for home fruit production.

Research and Extension - Woody Ornamentals

Phytophthora citricola causes both a root rot and trunk canker in over 45 species of plants, but has only been reported as a seedling root rot of black walnut. We have identified this pathogen as causing a stem canker of black walnut in Indiana, and are currently working on developing a better understanding of this pathogen so we may better manage this disease.

Photo provided by Guillermo Padillo	Black walnut scion inoculated with P. citricola, 36 hr post-inoculation

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Extension

As part of my extension responsibilities, I focus on training in disease management for commercial and home fruit growers, nursery, greenhouse, and landscape-care professionals.  My outreach is multifaceted, and includes field days, educational presentations at workshops, field trials, extension briefs and bulletins, popular books and magazine articles, and webpages.

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Teaching

BTNY 301: Introductory Plant Pathology
BTNY 518: Diseases of Landscape Trees and Shrubs

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Assistantships and Positions

Please contact me directly for information on assistantships and openings in my program. Follow these links for general information on graduate programs or employment announcements.

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Selected Publications

Beckerman, J., and Ruhl, G. 2007. Phytophthora citricola causes a stem canker in black walnut (Juglans nigra). Online. Plant Health Progress doi:10.1094/PHP-2007-0420-01-BR.

Beckerman, J. 2007. Proactive approach fights downy mildew best. American Nurseryman. April 1, 2007.

Mickelbart, M.V., and Beckerman, J. 2006. What you need to know about P. ramorum. American Nurseryman Nov 15, 2006. Pages 20-23. Download pdf file

Beckerman, J. 2006. Perennial Disappointments. GrowerTalks Volume 70, Issue 4 Pages 86-90.

Beckerman, J. 2006. Win the War with Fungi: Understand Your Disease Enemies and Your Control Weapons," Nursery Management & Production. Vol. 22, No. 5. Pages 50-54.

Beckerman, J. 2005. Fairly New Fungicides. American Nurseryman Magazine. Vol 201, Issue 12. Pg. 28-31.

Beckerman, J. 2005. Preventing Problems with Plants.  The Miracle Grow Plant Health Care Encyclopedia. Meredith Books. Denny Schrock, editor.