Mugo pine dying fast!

Asked July 22, 2015, 4:27 PM EDT

Last week I noticed an overwhelming amount of brown, dead areas on my mugo pine. It had appeared very quickly, and in the past week gotten worse fast. I had put some lime on the bush, which may have been good or bad, I don't know... Most areas are just dead needles, no brown spots/stripes, etc. The living needles have a white fuzzy area where the needle meets the branch. I found one bad area with white globs and mildew type growth. How do I treat it and is it too late?

Stearns County Minnesota mugo pine

6 Responses

A drastic change in a short amount of time in a large plant like this is usually serious.

While we can see some general browning throughout the tree, none of the photos are clear enough for us to see any details. Your description of the fuzzy areas at the base of the needles and the twig suggests either wooly aphids or pine bark adelgids:
http://www.extension.umn.edu/garden/insects/find/woolly-aphids-on-trees-and-shrubs/.
http://entomology.osu.edu/bugdoc/Shetlar/factsheet/christmasstree/pine_bark_adelgid.htm

These insects may simply be a sign that the plant is under some sort of stress, and the iinsects are opportunistically moving in. While repeated, heavy infestations of aphids can eventually weaken a tree, you have not indicated that this has been a yearly problem.

If you can provide some additional information, and send a few high quality photos of the woolly areas, the browning pattern and the affected needles we will try again.


Some questions:
Are the browning leaves at the very ends of the branches, in the middle or does it involve the whole branch? (If I were to guess, based upon these photos I'd say the browning was occuring on last year's growth).
Do you see any banding or speckles on the green leaves, closest to the affected areas?
Have you, or any of your neighbors used a broad spectrum herbicide in this area lately? This would include lawn treatments for broad-leaf control, or crop spraying in the area?

In the meantime, it's not a good idea to fertilize or otherwise augment plant nutrition unless you are certain that there is a nutritional deficiency going on.
Fertilization can speed up, and increase tender growth, which is very susceptible
to insect, herbicide, and disease assaults.

Here are a couple of fact sheets that you can look over to see if any of the symptoms match what is going on with your tree:
http://www.extension.umn.edu/garden/yard-garden/trees-shrubs/dothistroma-needle-blight/
http://plantclinic.cornell.edu/factsheets/sphaeropsisdiplodia.pdf
http://www.extension.umn.edu/garden/yard-garden/trees-shrubs/pine-needle-rust/

I will look for some photos and a further response from you.

Thanks for getting back to me so fast. To answer some of your questions: This is the first time I've had this problem. I don't know of any different herbicide used nearby this year than what's been used in the past. I used a weed-n-feed in early spring on the grass, but not under the pine. No crops nearby as far as spraying goes. One tough problem for this pine is that it sits at a hilly street corner that gets very heavy salt/sanding during the winter due to the school nearby. I don't know if this could affect the pine over time.

Many branches have totally died. The partly living branches have brown/dead needles are on last years growth and white powdery areas on this years needles (where the needle meets the branch).

Looking closer at the dead needles, there are some with spots and/or bands around them . One of my photos shows this. Another photo shows the white powder/fuzz that is in spots on some branches, and covers larger areas on other branches. The third photo shows the white milky substance that is present on those same branches.

In looking at your links, it seems that a couple of things are going on, both blight and maybe the aphids. I'm hoping to be wrong. Thanks for your assistance.






It looks like only two photos posted, so here are a couple others-

Trying again to post the photo of the milky areas.


Thanks for these excellent photos.
It does appear to be a disease, rather than some abiotic damage. As was stated in one of the articles, a lab analysis is probably necessary for an accurate diagnosis. Control options can then be started.
You may want to contact a certified arborist to get an opinion, but they will also prbably want a lab test.

Here is a link to the plant disease clinic at the university:
Plant disease clinic: http://pdc.umn.edu/

I hope I'm wrong! Good luck and thanks for contacting AaE.

Thanks so much for your help, Mary!