I have not heard of any oak wilt in Greeley, Colorado. That said, Master Gardeners of Weld County are meeting later this week. I can ask the Horticulture Extension Agent and members of the Tree Team of Weld County for additional, updated information.

What kind of oak tree do you have? What are you seeing?

Here’s some information for you about oak wilt:

https://storymaps.arcgis.com/stories/744ffe8e80df433e834d27d168a3aff8
https://plantdiseasehandbook.tamu.edu/landscaping/eight-step-program-to-oak-wilt-management/

Please send more information. Maybe some photos?

Thanks.

Sue
Weld County Colorado Master Gardener

Ned,
Here is information about leaf scorch: https://extension.colostate.edu/topic-areas/yard-garden/leaf-scorch-2-911/  Note photo #2.
Also, here's information about how to judge if your tree has enough water during this very hot and dry weather: https://extension.colostate.edu/topic-areas/yard-garden/leaf-scorch-2-911/  Many people have found the 6-inch screwdriver test to be very useful.  Simple, basic and you already have the necessary tool.
Stay cool!
Sue
Weld County Colorado Master Gardener

This afternoon, I just talked to Macaela Truslove, Weld County Horticulture Colorado State University Extension Agent.  No oak wilt in Greeley.  It is a disease that affects trees in the eastern U.S.  She suggested I send you information about "Drippy blight."  Note that Bur Oaks are not mentioned in this research article.  https://research.fs.usda.gov/treesearch/56723 
This bulletin has photos: https://www.internationaloaksociety.org/sites/default/files/pictures/2019%20Posters/Sitz%20IOS%202018%20poster.pdf
Is this what you are seeing, Ned? Please let us know!

By the way, since you are interested in plants and like to do research, have you considered becoming a Colorado State University Master Gardener?  Here is a link to more information: https://www.weldmastergardeners.org/Apply-to-Volunteer  

Sue, 
Weld County Colorado Master Gardener

You are very welcome, Ned.