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Mugo Pine #870889

Asked May 31, 2024, 7:24 AM EDT

My son has a mature mugo.pine which has developed orange colored clusters on the end of its branches. Many of the branches are being exfoliated. I sprayed the clusters as best I could with insecticidal soap thinking this may be worm larvae. I can try to send a photo but I may not be successful. How should we proceed. My son has other issues in his yard and I will send separate emails. Thanks for your help.

Carver County Minnesota

Expert Response

Those orange growths are pine cones - most of which will never mature into a true pine cone. That is the natural state of things - nothing to worry about.

The needles are another issue and it looks like this pine has had pine sawflies. They emerge in early to mid May and the larvae eat last year’s needles. They do not eat older needles or the new candles. 

There is nothing to be done this year. Watch for them to emerge next year in early May. The best way to control them is to either blast them off with a hose or to use an organic treatment like Captain Jack’s Dead Bug Brew which contains Spinosad. 

https://hort.extension.wisc.edu/articles/european-pine-sawfly/

https://captainjacks.com/product/captain-jacks-dbb-conc/

Deb Reierson Replied May 31, 2024, 10:15 PM EDT
Thank you.  Can we trim back the branches that have been exfoliated?

On Fri, May 31, 2024, 9:15 PM Ask Extension <<personal data hidden>> wrote:
The Question Asker Replied June 02, 2024, 1:53 PM EDT

I would not trim them back. They will still grow new needles this year and over time the damage will no longer be apparent. 

Deb Reierson Replied June 02, 2024, 4:25 PM EDT

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