Pine trees

Asked July 6, 2020, 12:01 PM EDT

What type of pine are they. Why are they dieing. One year they will have brown spots on them by the end of the next summer they are dead

Lac qui Parle County Minnesota

1 Response

Hello. Happy to help.

Great close-up photo of the needles! I can see the brown bands that tell me it could be either Brown spot needle blight (Mycosphaerella dearnessii) or Dothistroma needle blight (Mycosphaerella pini). Both are fungal diseases that affect Scotch Pines which is what I suspect your tree is but Scotch pines are more resistant to Dothistroma needle blight. Both are so similar in their presentation that it will take a lab analysis to determine which it is.

I recommend sending in a sample to the U of MN Extension Plant Disease Clinic for a definitive diagnosis. Here is a link to their website where you'll learn about their services, prices and how to submit a sample:

Here is more information about Brown spot needle blight:

Here is more information about Dothistroma needle blight:

I hope this information helps.