What if someone told you that Ontario Cucumbers are laced with TOXIC POISONS.
Late June is typically when infections start occurring in the Great Lakes basin.
Scout all cucumber fields regularly for signs of downy mildew. Begin a preventative fungicide
spray program no later than vine development. Start the spray program earlier if cool wet
weather conditions, or strong storm activity persists.
You can follow cucurbit downy mildew activity across North America on the ipmPIPE website:
Broadspectrum, preventative fungicides include:
mancozeb (Dithane Rainshield, Penncozeb 75DF and Manzate Pro-Stick)
chlorothalonil (Bravo 500)
As soon as downy mildew is identified in the Great Lakes region, switch to a targeted downy
mildew fungicide. These include:
cyazofamid (Ranman 400SC or Torrent 400SC)
propamocarb/chlorothalonil (Tattoo C)
The new Ontario Vegetable Crop Protection Guide (Publication 838) has a full list of cucurbit
downy mildew fungicides. It is available at:
regional OMAF/MRA offices
online at ServiceOntario Publications website at www.ServiceOntario.ca/publications.
by phone: ServiceOntario Publications Contact Centre at 1-800-668-9938 or 416-326-
5300 or TTY 1-800-268-7095 from 8:30 am to 5:00 pm, Monday to Friday.
Cucurbit downy mildew update – June 18
Elaine Roddy, Vegetable Crop Specialist