Dutch Elm Disease: What is it and Why should we care?

We have seen all the signs and warnings around the province telling us to protect against Dutch elm disease. But what is it exactly? 

Jeff Gooliaff, president of an environmental company that works within the province to protect our forests large and small, talked with West Central Online to answer all of our questions. 

“Well, Dutch Elm disease itself is a pathogenic fungus that, in a nutshell, what it does is when it gets into the vascular tissue of the American Elm tree, it will block the flow of water in the tree, it will also block the ...  sugars that are produced in the leaves during photosynthesis. So, it will actually block that flow of sugars from the leaves down to the roots where it's stored as energy, but also block the flow of water from the root.” 

Gooliaff also explained the reason the threat from this infection is so dire due to there being large numbers of American Elms in towns and on private land.  

“I wouldn't be shocked if there's 500 to 1000 American Elm trees in public spaces [In Kindersley], in the boulevards and parks. But you also could have 500 to 1000 American Elms on private lands, and it's a very it's a valuable tree. 

It grows in drought conditions. It does well in our growing climates, ... it's the largest shade species in our urban forest...” 
 

Dutch Elm Disease affected Tree curtesy of Living Tree Environmental

The reason there is a ban as strict as it is for April to August is due to one of the carriers of the very contagious disease, the elm bark beetle, are most active during this time. 

“Yes, [it’s] very contagious. So that's why we've got that pruning ban on from April 1st to August 31st and that coincides with the peak activity period for Elm bark beetle, which is one of the vectors or carriers of the Dutch Elm fungus ...  

[The beetles carry] the fungal spores in their mouth parts and they actually use those fungal spores, when they drill underneath the bark and get into the vascular tissue ... As they're creating their galleries under the bark, they'll drop those spores, and those spores will grow ... because they block the sap in the tree.  

Trees will often try and flush out the beetles because it's a foreign object under the bark, that those fungal spores will actually block the sap from flushing out the beetle. So, they actually use it as a protection device ... They work hand in hand...” 

More information is available here through the Saskatchewan Government website.