Manitoba, in general, had a slightly delayed start of planting in 2018; about a week later thanin 2017, reports Vikram Bisht in the first Manitoba Potato Disease Report of the season. The majority of planting started in first week of May, and mostly finished by the end of May. Early planted fields have good emergence. June 1 has been set for initiation/accumulation of P-Days and late blight Disease Severity Values. P-day is a measure of heat available for crop growth and development, and values accumulate when temperatures range between 7 C and 30 C.
Weather conditions since planting have been very warm, with a few days over 30 C. Precipitation has been below normal for May, except for a few scattered heavy rain events towards end of May. This week’s rain should help ingood emergence and stand.
The current soil temperatures are 2 C to 5 C warmer than end of May last year. These warm soil temperatures and may speed up emergence.
Cull piles are an important source of inoculum for many diseases including late blight. It is important to dispose of properly the cull piles before thunderstorms arrive.