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Ontario early potato crop progressing well for harvest

Ontario potato crop is progressing well across the province and the harvest of early potatoes for the fresh market is expected to start by July 18 in southwestern Ontario, according to potato specialist Eugenia Banks’ latest update.

So far dig tests across the province have shown excellent quality.

In the Simcoe-Delhi area, grower Joe Lach shared how the area has experienced timely, moderate rains. The plants in the area looked healthy with no indication of stress. The perfect temperatures and timely rains contrast the dry growing season experienced in some parts of Ontario last year. “[This year is the] best growing season I’ve experienced here in 40 years so far,” Lach added.

In the Alliston area, grower Bill Vasily shared that there are solid fields in the region with rows closed and beginning to flower. The majority of these fields were the earliest planted fields, but there are some late planted fields that have uneven progress. Weeds, such as ragweed, could be a problem for some of the late planted fields.

Despite adequate rainfall in the Alliston area, some fields have required irrigation. Banks shared how she did not find any insect pests while scouting the region, but did notice a field showing stress from the high heat and humidity.

In the Shelburne-Melancton area, the potato crop was younger and looked healthy. Banks said the challenge for the Alliston and Shelburne-Melancton areas will be the lack of rain by mid-summer and in August when the crop is in its bulking stage.

Pest watch

There have been no reports of Colorado potato beetle infestations in fields planted with treated seed. So far neonicotinoids are working well, but Banks advises growers with early planted fields to closely monitor the situation. The activity of neonicotinoids starts to break down approximately 60 days after seed treatment.

Growers are also advised to keep an eye out for European corn borer. Potatoes are the next preferred host for the pest when corn is late, and in Ontario the corn season got off to a late start because of cool, wet weather. Therefore the delayed corn season could see a rise in the risk of European corn borer for Ontario’s potato crop.

Banks shared that two other pests to keep an eye out for are armyworms and black cutworm. The larvae of armyworms invade potato fields when looking for cereal hosts, and given the varied progress of cereals in Ontario, 2019 may be an armyworm year for potatoes.

When scouting for black cutworm, Banks says to look for shotgun holes in leaves. Other signs of damages besides leaf feeding, are wilting, cut stalks or odd angles of the crop. The second generation larvae for black cutworm are active from mid-July until August. Growers are encouraged to check around damage areas, up to half a metre around the feeding damage, and look under dirt clods. Feeding worms usually emerge in the evening. If 10 per cent of plants show signs of feeding damage, growers are encouraged to spray in the evening. In 2018, black cutworms were found in a number of fields near Delhi, Ont. near the end of July.

Early season black cutworm damage. Photo courtesy of Eugenia Banks.