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Disease, Pest or Something Else? #752285

Asked May 26, 2021, 1:21 PM EDT

Can you help identify whats wrong with this Pinus Contorta 'Spaan's Dwarf'? The plant has been growing in this location for about 4 years. The site faces east and is in shade most of the afternoon. There is a drip irrigation hose that is used during dry spells. soils are clay/silt/loam glacial till that is slightly alkaline.

Washtenaw County Michigan

Expert Response

Ken, thanks for the question.

After doing some research on this species it appears that the shade is most likely the culprit. This tree is struggling and suffering from possible dothistroma needle cast.  USDA plant database says it is intolerant to shade. Although the database indicates it is tolerant of clay soils, good drainage is required. Check out the following links:

I hope this is helpful.

An Ask Extension Expert Replied May 28, 2021, 4:27 PM EDT
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Hi,
While the tree is in shade from about 2pm on, please see the photos.  It looks like some kind of fungus.

Thanks,
Ken


On Fri, May 28, 2021 at 4:27 PM Ask Extension <<personal data hidden>> wrote:
The Question Asker Replied May 30, 2021, 2:03 PM EDT

The last pictures clearly shows scale insects (striped pine scale) . The black is sooty mold growing on the honeydew and feces of the female. Check out the following links for control information:

https://www.canr.msu.edu/news/soft_scales_of_spruce_and_pine

https://extension.psu.edu/striped-pine-scale

https://www.canr.msu.edu/news/striped_pine_or_tortoise_scale

An Ask Extension Expert Replied May 31, 2021, 8:21 AM EDT

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