Previous 2014 late blight updates: July 25July 13, July 3.

OMAFRA has confirmed the presence of late blight in a potato sample from Simcoe County. A sample of the disease has been sent to Agriculture and Agri-Food Canada in Lethbridge, Alberta for strain typing. There are no reports of late blight in Ontario tomatoes so far this season. Late blight has been spreading in the Northeast US.  In recent weeks, reports of late blight have been made in New York, Michigan, Indiana, Maine, Pennsylvania, Wisconsin, and Massachusetts (http://usablight.org/). Continue Reading »

OMAFRA staff have identified a suspected case of late blight in Simcoe County on potatoes. The sample has been submitted to Agriculture and Agri-Food Canada – Lethbridge, Alberta for lab confirmation.

To date, there are no reports of late blight in tomatoes in Ontario. Late Blight has recently been reported in potato and tomato fields in several Northeastern states.

For more information on identifying and managing late blight in tomatoes see:

2014 Potato Field Day


2014 Potato Field Day (pdf version)

Originally posted on :

Cucumber beetles are the primary vector of bacterial wilt.  Even a fairly low population of beetles can spread this disease across the field.  Once infected, there is no cure for this disease.  Plants will rapidly wilt and die, effectively reducing the plant stand and the yield potential.  Cucumbers are the most susceptible to bacterial wilt followed by melons, pumpkins and zucchini.

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July and August are such busy times in agriculture, and vegetable farms are some of the busiest of ag operations.  There is so much to do, and often so little time for sleep.  Always keep safety first and foremost as we head into peak harvest season. Stay safe my friends.

There are low levels of powdery mildew showing up in the pumpkin and squash plots on campus this week.  Powdery mildew is the most important disease of pumpkins and squash. Melons and cucumbers are less susceptible, although infections also occur in these crops.

Powdery mildew does not overwinter in Ontario.  It typically appears in late-July each year. While some varieties have a good level of resistance to this disease, many do not. Severe infections result in decreases in yield, sugar content and harvest quality. Control is especially important in Halloween pumpkins where infections cause the stems to decay resulting in poor (or absent) handles.

Many of the products commonly used for downy mildew control in cucumbers do not control powdery mildew.  Despite the similar names, the two diseases are quite different. Each disease has its own set of registered fungicides. An effective fungicide program for pumpkins and squash is very different from one used in cucumber crops. Continue Reading »

Late blight foliar lesions

Late blight foliar lesions

Previous 2014 late blight update: July 3.

There have been more late blight confirmations over the last week or so in the US Northeast.  Here’s a summary, with the late blight genotype in brackets, if known:

  • July 10 – Suffolk County, Long Island, New York – tomato
  • July 9 – York County, Maine – potato
  • July 7 – Lagrange County, Indiana – potato (US-23)
  • June 27 – Prince Edward Island – tomato
  • June 27 – Lancaster County, Pennsylvania – potato and tomato (US-23)
  • June 26 – Chester County, Pennsylvania – tomato
  • June 26 – New Brunswick – tomato
  • June 23 – Erie County, New York – potato (US-23)
  • June 21 – Cambria County, Pennsylvania – potato (US-23)
  • June 13 – Suffolk County (Long Island), New York – potato (US-23)

To date, I know of no confirmed cases in Ontario. See Late blight update – 2014 07 03 for recommendations on how to protect your tomato crop if late blight is found in our growing areas.

A note on the late blight genotype found so far in the US Northeast in 2014: US-23 is known to infect both tomato and potato.

Tomato Late Blight Photo Gallery


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