Good Morning Gary, 

Thank you for contacting the U of M Extension Service. 

Please click on the following link from the U of M Extension Yard and Garden website: 

https://extension.umn.edu/fruit/growing-stone-fruits-home-garden

Under the diseases, this information states: 

• Trunk canker diseases can form in the trunks of tender stone fruit trees after winter injury or other injuries caused by wounds in the trunk. These diseases enter the trunks through the wounds and gradually kill the trees over several years, by cutting off water and nutrient movement through the tree. Prevent this by planting cold hardy varieties, which are more resistant to winter damage.

There is an entire section devoted to winter protection of the trees. 

Good Luck!