A note from Meg McGrath:
Late summer into fall is when conditions are most favorable for downy mildew to develop on brassica (cruciferous) crops. I am very interested in hearing if you are growing any of these crops and you see symptoms, especially on collards and arugula because I am aware of only one occurrence on each of these crops in the region. Knowing about on farm occurrences will help in determining degree of host specialization in the pathogen causing DM on all the brassica crops. I’ll also be interested to hear at season end if you don’t see any symptoms of DM on your brassica crops to provide perspective for how widespread the disease occurs. Samples are needed for research if you see DM and can make the time (I realize you are super busy during the growing season!) to collect and box up some leaves to send to a colleague (pre-paid label will be provided). Please contact Meg at mtm3@cornell.edu if you think you have this disease.
If you don’t know what downy mildew in brassicas looks like, I have photos at https://blogs.cornell.edu/livegpath/gallery/.
Margaret Tuttle McGrath
Plant Pathology and Plant-Microbe Biology Section
School of Integrative Plant Science
Cornell University
Long Island Horticultural Research & Extension Center
3059 Sound Avenue
Riverhead, NY 11901-1098
Phone: 631-727-3595 ext 20
