Late blight has been confirmed in Manitoba in the rural municipality of Norfolk Treherne, the south central potato growing region in the province.
The region had heavy rains last week in the area. Leaf spot infections appear to be scattered close to the irrigation pivot. The infected leaf spots have sporulation and there are a few infected stems as well. Samples are being inspected for strain identification.
According to Vikram Bisht, plant pathologist, potato and horticultural crops, Manitoba Agriculture, widespread rains yesterday (Aug. 9) mean conditions will be very favourable for late blight disease. “It is important that all fields are scouted very diligently.”
Application of translaminar fungicides along with protectant fungicides should be considered. In fields with new disease incidence, fungicides with a “kick-back” effect could be considered.
This is the time for home gardeners to check their tomato and potato plants very carefully for possible late blight infection. Early blight and septoria leaf spots diseases on tomato are different from late blight disease. Both diseases normally start from lower leaves, tend to move upwards and often cause some yellowing of leaves. Protectant fungicides may be applied as soon as possible. There are copper fungicide options for organic production.
