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Dr. Rishi R. Burlakoti, Research Lead and Plant Pathologist, Weather INnovations Consulting LP

Weather INnovations is currently providing several crop management tools for Ontario Vegetable Growers at www.vegtools.ca. The website provides fungicide timing advisories including TOMcast™ for early blight, Septoria, and Anthracnose and late blight advisory TOMcast DSVs 20150701for tomato growers. Fungicide timing advisories are also available to manage foliar blights of carrot and celery as well as purple blotch of asparagus. The website also provides growing degree day-based scouting advisories for 12 different pests of several vegetable crops including cole crops, tomatoes, onions, garlic, carrots, leafy vegetables, snap beans and cucurbits. Without login, growers can get information on the available crop management tools as well as short description of diseases and pests. To get site-specific advisories, growers require to login and register their fields. All these site-specific tools can be accessed without subscription fee.

The guidelines to access site-specific TOMcast™ and other tools are described below: Continue Reading »

With the pattern of wet weather that seems to have set in after what was, in some areas, a dry start to spring, the moisture-loving tomato diseases will thrive.

Although research has shown no significant benefit to spraying for bacterial spot on tomatoes (except for the marginal benefits of an intensive copper + Actigard program), it is very important to have a fungal disease management program in place now.

Continue Reading »

Both rust and purple spot (stemphylium) thrive under cool, wet conditions. Scout fields regularly, at least 2 times per week under high disease pressure conditions.  Inspect a minimum of 100 plants per field; looking closely at the bottom 24″ of each stalk. Foliar diseases often first appear in immature and newly planted fields. Continue Reading »

Last week’s confirmation of downy mildew in both Kent and Elgin was unusually early. Recent reports have also been made in Michigan and Ohio. As a result, we are in the unfortunate situation of having to “stay ahead” of the disease this year.  Here are a few additional thoughts to help manage this aggressive disease in what appears to be a high pressure year.

  • Rotate! Research at Ridgetown Campus has shown that the “best” product does vary from year-to-year, and that all of the products have had years where they did not perform as well.  To rely on one or even two products puts the crop at risk should one of those products fail, or if resistance develops.  Use at least 3 different products from different fungicide groups.
  • If at all possible, spray BEFORE a forecast rain event.  While several of the products have a limited amount of curative properties, they all work best when used preventatively.
  • If downy mildew is present in your field, shorten the spray interval. Especially if rain is forecast in the immediate future (see above).
  • All leaf material is susceptible to downy mildew infection, even the cotyledons.  Begin a preventative program in new plantings as soon as they emerge.
  • Scout fields regularly, especially fields in which downy has not yet been identified.  And by regularly, I mean daily! The disease can progress significantly in just a few days.  I have seen fields go from “watersoaked” lesions to spore producing brown lesions in less than one day.

Ranman 400SC/Torrent 400SC

In response to the issue regarding the use of Ranman 400SC the PMRA has issued this response: “The RANMAN 400SC AGRICULTURAL FUNGICIDE (Reg. No. 30716) was recently amended to remove all uses except potatoes. With respect to product bearing the previous label,(i.e. just prior to the latest amendment), the PMRA would have no issue with this previously purchased product being used on cucumbers for the 2015 use season. Any purchase of product bearing the newly amended label however, will ‎need to be used in accordance with the new label.”

Moving forward, cucurbit growers are reminded that Torrent 400SC is now the registered formulation of cyazofamid for the control of downy mildew in this crop.

Ridgetown Vegetable Open House

Ridgetown Vegetable Open House

For commercial vegetable growers and agribusinesses.

Tuesday, July 14th, 2015
Selton Line and Ridgetown Campus
Choose an afternoon or evening tour
Your choice of: 1:30 – 4:30 pm or 6:00 – 9:00 pm

Get the poster (pdf) with map and directions.

Hosted by OMAFRA & Ridgetown Campus – University of Guelph Continue Reading »

Early foliar symptoms of late blight

To date, I know of no confirmed cases of late blight in Ontario or nearby states, but there’s a report today of it showing up in Wisconsin. Nevertheless, our experience of recent years would indicate we are likely to see it in Ontario tomatoes at some point in the season.

Remember that conventional tomato growers using a recommended fungicide program for early blight, septoria leaf spot, and anthracnose, are also protecting the crop from late blight infection. Cloudy and high humidity or wet conditions are favourable for late blight.  The pathogen prefers cool temperatures.  The disease is suppressed by hot, dry weather, but it can continue developing and spreading when suitable conditions return.

If late blight is found in the area, tomato growers should: Continue Reading »

Trace amounts of downy mildew were found in a Kent County cucumber field today by the University of Guelph, Ridgetown Campus, scout.

All cucumber growers in Ontario are advised to begin a preventative downy mildew spray program using targeted downy mildew fungicides. For more information fungicide selection, see the Ontario 2015 Downy Mildew Control Strategy for Cucumbers. Growers are also encouraged to monitor their own fields for early signs of infection (see figure 1, below).

Current weather conditions are very suitable for the spread of this very aggressive disease. Under these conditions, with downy mildew in the area, a 7-day spray schedule is warranted.

water-soaked lesion

Figure 1. Cucurbit Downy Mildew – water-soaked lesion

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