The 2018 downy mildew season has had a slow start. The Southern United States had their first reported case of downy mildew in Florida on May 16th, with additional reports in Georgia and North Carolina on May 25th and 30th (respectively). This is an unusually late start to the DM season, with this disease typically developing in Florida in February or March.
Historically, downy mildew has arrived in Southern Ontario between late-June and early July. The latest it appeared in this area was in 2014, following unusually low disease conditions in the Southern US through the spring months.
Summer storms and the level of inoculum in the environment have a significant impact on the progression of the disease throughout the summer. An active hurricane season could facilitate the survival and transportation of downy mildew spores.
For regular updates on the progression of downy mildew in the US and for CMD forecasts, visit the Cucurbit ipmPIPE website.
Downy mildew is a community disease. Knowing exactly where the disease is active is a key component to the timing and selection of fungicides.
CDM Epidemic History
|Year||First North American Report Date||First Ontario Report Date|
|2018||May 16||not at all would be fine by me!|
|2017||February 17||June 28|
|2016||March 18||July 6|
|2015||January 21||June 24|
|2014||February 27||Aug 13|
|2013||February 19||July 10|
|2012||February 1||July 5|
|2011||February 14||July 5|
|2010||March 26||June 18|
|2009||January 12||June 29|
|2007||March 1||June 28|
|2006||March 1||June 12|