Cornell UniversityCollege of Agriculture and Life Sciences
Department of Horticulture
Department of Plant Pathology
  and Plant-Microbe Biology

Department of Entomology
CCE of Suffolk County
Long Island Horticultural Research and Education Center
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Serving the research and extension needs
of Long Island's horticultural industries.


Vegetable Pathology contact:

Dr. Meg McGrath
mtm3@cornell.edu
3059 Sound Ave.
Riverhead, NY 11901
(631) 727-3595
(631) 727-3611 (fax)

All photographs in this gallery were taken by Meg McGrath unless otherwise noted. For permission to use Meg's, please email her: mtm3@cornell.edu
 

Downy mildew on basil

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These images show first symptoms of downy mildew found on untreated plants in a home garden. First three photographs taken on 9 August 2009, the rest on 12 August 2009.

Following eight images show first symptoms of downy mildew found on untreated plants in a home garden. First three photographs taken on 9 August 2009, next five taken on 12 August 2009.

Yellowing on upper leaf surfaces.
downy mildew on basil

Pathogen growth and spores on lower leaf surfaces.
downy mildew on basil

Close-up of pathogen growth.
downy mildew on basil

Yellowing on upper leaf surfaces.
downy mildew on basil

Pathogen growth and spores on lower leaf surfaces.
downy mildew on basil

Close-up of pathogen growth.
downy mildew on basil

Close-up of pathogen growth.
downy mildew on basil

Close-up of pathogen growth.
downy mildew on basil

Basil downy mildew in a commercial crop. (Photo courtesy Maire Ullrich, Cornell Cooperative Extension-Orange Co., N.Y.)
basil downy mildew in commercial crop

Basil downy mildew in a commercial crop. (Photo courtesy Maire Ullrich, Cornell Cooperative Extension-Orange Co., N.Y.)
basil downy mildew in commercial crop

Basil downy mildew in a commercial crop. (Photo courtesy Maire Ullrich, Cornell Cooperative Extension-Orange Co., N.Y.)
basil downy mildew in commercial crop

Basil downy mildew in a commercial crop. (Photo courtesy Maire Ullrich, Cornell Cooperative Extension-Orange Co., N.Y.)
basil downy mildew in commercial crop

Next two images: Sporulation of the basil downy mildew pathogen abundant on the lower leaf surface and also present on the upper surface of leaves of infected commercial basil plants kept in high humidity (inside a plastic bag) over night.
basil downy mildew in commercial crop


basil downy mildew in commercial crop

Below: Sporulation on container grown plant kept outside (left) but not on plant brought inside at night (right). More information.

basil downy mildew

Below: Sporulation on both surfaces of small leaf.

basil downy mildew

Below: Sporulation on upper surface of large leaf.

basil downy mildew

Below: Sporulation on wet leaf with dew drop.

basil downy mildew

More images of downy mildew on basil at the Cornell Vegetable MD website

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Copyright by the Department of Horticulture Website at Cornell University.