Tree and Horticultural Management Services

Local Crepe Myrtles Are in Trouble!

Our beloved crepe myrtles are under attack by an exotic pest from Asia called Crepe Myrtle Bark Scale. 

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This pest has slowly spread into our area and now I see the damage it has created in practically every single area in Birmingham, Alabama. Crepe myrtles have been such a solid staple in our southern landscapes my whole life. They are hardy small trees with little fuss after establishment. Especially the Indian-named cultivar varieties such as Natchez. While some crepe myrtles have problems with powdery mildew and occasional aphid infestations, there isn't another small tree that can provide 90-120 days of bloom. 

 

This is devastating! We have so many crepe myrtles planted in our area it's difficult to even speculate how many without it sounding like an exaggeration. Easily tens of thousands have been planted. In the summer of 2022, I began to see this pest spread like wildfire. Calls flooded into my office with clients needing answers. 

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Crepe Myrtle Bark Scale (CMBS) and what you need to know.

 

This pest was first reported in North Texas in 2004. The Crepe myrtle bark scale has spread into 14 different states. Adult (CMBS) females are small whiteish felt-like encrustations which form on small twigs and large main trunks of crepe myrtles. They feed on the sap of the crepe myrtle and excrete a clear "oil-like" liquid that rains down all over the tree, limbs, and leaves. This is their waste and is generally referred to as honeydew. CMBS waste is prolific and heavy infestations of crepe myrtle bark scale create a constant wet, sticky environment underneath the tree canopy. 

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There is a fungal pathogen that grows on the honeydew called sooty mold. This sooty mold turns all this clear honeydew waste a black color. This is usually what gets the attention of tree owners. The leaves, trunk, and stems all turn black from sooty mold. Additionally, plants, driveways, sidewalks, and even vehicles under the crepe myrtles turn a blackish color. It's simply NASTY! No one wants to have insect waste all over their patio. Imagine having the family or friends over for a cookout when it feels like it's raining but the sky is clear. It's raining insect waste...YUCK!

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I've seen crepe myrtles that look completely black. This doesn't normally kill the tree, but heavy infestations can cause premature leaf defoliation and weaken the tree. If your tree is already black, it will take some time for black bark to fade. Many crepe myrtles have strips of thin bark which peel off the tree each year and this will aid in returning the tree to its natural color. The leaves will likely remain black until they drop in the fall. 

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If ignored the CMBS will only get worse. Early identification and treatments are important. There are many treatments that are ineffective and a waste of time and money. Don't rely on the average "tree and shrub" service to provide effective treatments. There are also certain times of the year to apply selected insecticides. Federal law restricts systemic and contact insecticide applications to prevent the killing of honeybees and other pollinating insects. This is serious and can lead to a large fine and/or jail time. If you think treating your tree during the wrong time of year doesn't matter; I would encourage you to consider how low our bee population is currently. There are places in China where there are NO pollinators. People must manually pollinate their crops, orchards etc. It's a serious matter.

 

If you want professional, environmentally friendly, guaranteed results to control Crepe Myrtle Bark Scale, contact me today. David W. Boggan 205-854-3676