I have a grove of blue spruce 10 trees to a row by 6 rows . I think they may have Needle Cast ( I posted picture online ) an arborist thought that might be the problem. How do I find out for sure and get started treating . The first row is 25 years old and on down thru the years
St. Clair County Michigan
You may submit branch samples with infected needles and green live healthy needles attached. Include pictures of the a couple whole trees and close up picture of an infected branch.
Call the MSU Plant and Pest Diagnostic lab before you submit samples. During Covid-19 this is necessary.
Here is the lab website with fee schedule, submission form and instructions-
Treatment may need a certified arborist who has access to special equipment and chemicals. You can search for arborists by zip code at their website. A certified arborist is a professional who has taken training in care, diseases, pests and passed certification tests.
In future, please attach your pictures here by clicking on the “Choose file” button and following the prompts.