Rainfall in the week (Monday, Sept. 16 to Sunday, Sept. 22) was extensive in distribution in the province, and heavier than last week. The weather station sites recorded 2 to 4 inches of rainfall. This week’s rainfall has put the total rainfall over the 30-year average for most areas in the province. The temperatures were generally warm (>28 C) early last week, but have dropped in the last two to three days (<15 C). The soils have been warm and moist/wet.
Potato harvesting has been frequently interrupted due to rains. About 30 to 60 per cent of crop has been harvested in different areas. Yields appear to be as good as last year, if not better.
In warm and moist/wet soils, there is a risk of pink rot and Pythium leak infection in potatoes. It will help if partly damaged or rotting tubers are graded-out prior to storage. Avoid harvesting low spots in fields, which may have been wet for some time. Such spots could be harvested later, if weather permits. Phos-Acid fungicides post-harvest treatment could be considered for managing pink rot. Phos-Acid’s affect on Pythium leak is not well understood.
Late-season severe early blight is appearing in some fields; but is not consequential at this stage.
The 10-day forecast (http://www.mbpotatoes.ca/weather.cfm?stn=212#btm) indicates more rains on Sept. 28 to 30, interspersed with light frost -1 to -2 C in some areas.