By Vikram Bisht
July 27, 2016, Manitoba – Several fields in western Manitoba (Carberry area) reportedly have light blight symptoms, according to Vikram Bisht's latest potato disease reports.
Some photographs of the diseased leaves show symptoms typical of late blight. Three samples received have been confirmed to have sporangia. The infections are mostly on the top foliage and found in pivot wheel tracks, along the irrigation gun run and edge of field in low areas. There are very few infected plants in the fields and they are difficult to find. The five-day spray schedule in these high risk fields may have kept the infection low.
So far, there is no report of late blight from any other part of Manitoba. The DSVs (late blight risk values) accumulated over seven days at various weather stations continue to suggest high late blight risk in most of the province.
It is extremely important to scout for late blight now, especially in low lying, irrigation pivot center, wheel tracks of irrigation systems (guns/pivots) and tree-line protected areas. It is also critical at this time to monitor potato and tomato plants in home gardens.
There is no forecast for rain events for rest of the week, but it will be warm.