By Vikram Bisht
Potato & Horticultural Crops, Manitoba Agriculture, Foods and Rural Development
There have been scattered and heavy rains (31Aug and Sep 4) in many potato growing areas. Based on the 7-day DSVs, late blight risk is low in southern part, moderate in the western and central province and high in the central north (Portage La Prairie area). However, so far there is no late blight report in Manitoba. Field scouting and a 7-day schedule of fungicide application are still recommended.
Most of the seed potato fields are being desiccated. Desiccation of commercial fields will start soon. It is important that the vines be completely desiccated; else there is still risk of late blight.
Late blight has recently been found and reported (last week in August) from Saskatchewan (Saskatoon and Outlook). The strain identification is not available yet. With this report, BC, AB and SK now have late blight. With westerly winds and rain clouds, are we in MB still lucky. Ontario, NB and PEI have also reported late blights.
New late blight incidences reported in Washington (potato), Oregon (potato), Idaho (potato), Minnesota (potato), Ohio & Pennsylvania (tomato), Maine (potato), and New York (potato, tomato). No report from North Dakota.