Mugo pine candle drop-off and white specks on needles

Asked June 16, 2020, 2:50 PM EDT

Good afternoon! Thank you in advance for any help you may provide. I am a homeowner (not licensed to apply pesticides or herbicidesf). I have 3 small mugo pine shrubs that I planted in the fall of 2018. They are only about 24 inches across and 12 inches tall. Last spring, one of the 3 pines exhibited lots of "white paint splatters" on many of the needles that are located near the branch tips, and some of the lead candles turned brown, curled over, and dropped off. This spring, 2 of the 3 mugos exhibited the above characteristics. My 3rd mugo looks to be relatively problem free - so far. From doing Google research, I'm thinking they have Pine Needle Scale. None of the photos I found or text I have read mentioned Pine Needle Scale causing problems with the leaders/candles, so I am not 100% certain it is scale. I haven't been able to rule out Diplodea Tip Blight, from my meager research abilities. I have attached photos I took from my mugos. Would you please identify the problem for me, and also let me know how and when I can treat this problem? Thank you so much! GO GREEN!! Sparty Mike

Livingston County Michigan

1 Response

Pine needle scale will not cause the leaders to brown and wilt. Diplodia can injure the new growth. At this point in the season all you can do is prune out the dead tips. You may see black fungal pustules coming through the base of needles with Diplodia. Avoid overhead irrigation especially in the evening which keeps plant wet through the night encouraging the disease. Use of fungicides is recommended in spring see the following article https://www.canr.msu.edu/news/diplodia_tip_blight_management_in_trees
Pine scale will likely get worse if not treated. The manageable part of the insect's life cycle is the newly hatching crawlers. There are two generations that hatch out in the summer, the first around the last of May and the second coming up around mid-July. Watch for tiny brownish-red crawlers emerging from the white scale. These are easily seed on the needles when they hatch and begin to spread over plant and this is the stage to treat for them to reduce their impact on the plant. Horticulture oil is used to spray the young crawlers. See the following article: https://www.canr.msu.edu/uploads/files/e2812.pdf