Potatoes in Canada

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Manitoba potato disease report: Sept. 15


Sept. 15, 2015, Carman, MB – Manitoba has its first positive report of late blight, writes Vikram Bisht, with the potato and horticultural crops department at Manitoba, Agriculture, Food and Rural Development, in the latest potato disease report.

September 15, 2015
By Dr. Vikram Bisht/MAFRD


Late blight was confirmed in a sample received on Sept. 11. The infection appeared very late in the season and harvesting is in full swing.

A visit to the field in Carberry on Saturday showed the infection spots are mostly on the top foliage and fine branches.

There was a thunderstorm on Sept. 4, and more rains on Sept. 5 and 6.

A second field, within a mile of the first field, was also found to be positive for late blight, with scattered spots, mostly on top foliage. The sample was confirmed positive for sporangial production.

Strain identification work will be initiated soon.

There is a possibility of more fields in the area having late blight. Growers and a few neighbours and agronomists have been informed.

Nightshade weeds nearby were also late blight infected.

Scouting is critical now, mainly in wind sheltered areas and the dips in a field where the foliage is greener compared to the senescing crop around it.

Especially in fields which have a few more weeks to harvest, fungicide application to protect the crops is very important, and including systemic (translaminar) fungicides could be considered.

Dew and rains could take the spores to tubers close to the surface. There is a forecast of precipitation in the mid-week.