Pine tree with black dots

Asked October 27, 2017, 1:00 PM EDT

hello i have a pine tree (austrian?) with black dots on the needles. not scale, this is a smaller flat black spot. there are also very small dk gray/black insects. where can i go to get a diagnosis on this? there also seems to be more than the normal needle drop and the lower branches continue to be unhealthy. i am new to the area and live in SE Bend. thanks, kim oblak 316 706 8821

Deschutes County Oregon

1 Response

Thanks for your question about your pine tree's problems, Kim. From what I can see and your explanation, I'm concerned that your tree might have Dothistroma needle blight, which is described in this USDA article, as well as this OSU plant disease handbook article. However, as the second article indicates, the needles need to be examined under the microscope to distinguish it from other needle casts. The treatment that is available to the home gardener (listed in the second article) are those marked with an "H" in a box, but the exact pathogen should first be determined.

I suggest you take your photos and some needles, both healthy and not so, into the Deschutes County Extension office, 3893 SW Airport Way, Redmond (8 to 5), phone 541-548-6088, to seek confirmation.