Need much more information to make any kind of guess! Is drainage good? Salt damage from winter? Did it get enough water last summer and fall? (many areas were very droughty). Looks more cultural than pathogenic to me but another possibility is tip blight.

Take a portion of the affected twigs/branches into your extension office for a proper diagnosis. They will also recommend treatment if tip blight/canker is the issue.

Drainage is good and watering is good. No salt damage. It has been growing good (untreated) for the past 5 years I have lived in this home. It is dropping needles, primarily from the underside and the shadier side. Looks like the tips brow, curl up and drop needles. Appears to have new apical growth this spring, but I think it is dying faster than it is growing.

Diplodia tip blight is a disease mugho is susceptible to. I can't diagnose it by the picture, but it took a beautiful mature austrian pine of mine and is starting on yet another younger tree. It is endemic to certain localities and you may want to find out if yours is one of them.

interior browning.. and loss of needles is entirely normal ...

no pine holds its needles for more than 3 years ...

and all pine are full sun plants ... and yours .. from the pic.. is in shade ...
how much direct full sun does it get ...????

nothing dies for lack of full sun ... but they start getting leggy and sparse ... just like yours seems to be doing ...

prune out the brown parts.. ignore the interior.. and hope for the best ... i would not jump to spending money.. curing a disease.. if its not in enough sun ...

does it get wet often ???? ... as in using your hose and spraying it down in the evening?????

ken

Thanks all for the suggestions.

Ken, The tree next to the pine has gotten significantly larger over the years, I will cut it back to give more sun to the pine.

Calliope thanks for the suggestion of Diplodia i will Google it.

It was suggested to me that the pine might have spider mites. Thoughts and treatment?

Not spider mites. Very likely the Diplodia, which is the tip blight I referred to also. Take in a sample to your extension service for ID and treatment recommendations.

After reading your message and considering my other plants, I think my Juniper has tip blight too! I looked it up and though it is clearly a different fungus that causes the problem in Juniper, the pictures certainly resemble that of my shrubs!

How do I rid my evergreens from fungus!? Assuming it drys out soon outside (we had a wet winter and cool spring)...might the fungus die? Please advise on treatment, I live in the NE.

The tree next to the pine has gotten significantly larger over the years, I will cut it back to give more sun to the pine.

===>>> NNNNOOOOOOO!!!!

leave the pine alone..

go buy another mugo. and plant it in full sun.. and then get rid of this one.. when it fails ..

crikey .. you are going to cut on a presumably healthy pine in hopes of saving a sickly mugo ... yikes ...

it may also be starved for water under what is now a huge pine tree ...

ken