Hi Everett, 

I'm not aware of any classes that focus on needlecast. However, the best publication I've found to date is from the University of Minnesota, which explains needlecast in great detail. 
https://extension.umn.edu/plant-diseases/rhizosphaera-needle-cast

In Michigan, needlecast is most commonly found on Colorado Blue Spruce. Despite its beautiful form and color, some trees are highly susceptible to the disease as it's native range is the foothills of Colorado, which are usually dry (in the rain shadow of the Rocky Mountains). Other trees are not nearly as susceptible. The difference is attributed to genetics of the individual tree. 

We occasionally find needlecast in Norway spruce, and rarely in white spruce (unless it is grown under stressful conditions). Norway spruce is not native to Michigan, and it's home range is more similar to Michigan weather conditions. White spruce is native to Michigan. 

I didn't find any credible webinars on the subject. Below is a link to a short video I found:

Thank you,
-Julie