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The 2015 season: how is the potato crop doing?

Eugenia Banks, OMAFRA

Growing potatoes is always a challenge for Ontario potato producers.  Mother Nature dictates crop development from planting until harvest, and whatever she decides is beyond growers’ control.

April was a relatively quiet, spring-transition month. There were, however, a few typical storm systems that brought moderate amounts of rain. Planting started in Leamington just before Easter; by April 15, the sprouts of early varieties such as Dakota Pearl were looking healthy and vigorous.

Planting was delayed a bit by cool weather and the occasional rain shower in other areas of Ontario.  May was very dry which resulted in non-stop planting.  A large potato producer in Shelburne told me that he finished planting in May, something he had not done in years. 

In the early hours of May 23, Mother Nature sent a frost to most of the province.  Leamington was spared, good fortune for the earliest potato-growing area in the province.  The frost set the crop back at least 2 weeks. Fortunately, there had been little planting in April, so the crop was at a stage where the plants could recover quickly when warmer weather returned.

After a dry and frosty May, heavy rain in June washed away any concerns about dry soil during crop establishment.  Cooler temperatures and good soil moisture in June were meant ideal growing conditions; fields were lush and healthy with closed rows by the end of July.  Wet weather and cool temperature work wonders for potatoes but also provide ideal conditions for one of our formidable foes: late blight.

The disease was found in a few fields in early/mid July, The late blight strain was identified as US 23, a strain which is susceptible to Ridomil.  Applications of this fungicide dried up lesions.. Then, hot, dry weather arrived by July 19. Temperatures above 300C put the crop under stress for about 2 weeks.  The pivots and travellers had been resting in June but were working full time by the 3rd week of July.  Cooler weather that should relieve the heat stress started at the beginning of August.

Early processing and fresh-market varieties are being harvested in most of the potato production areas of Ontario.  Quality is reported to be very good.  The mid-season crop is senescing  and will be top-killed soon.  The late crop is at the bulking stage; with any luck, there will be well-distributed rainfall for the rest of August!

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