We recommend contacting an arborist certified with the International Society of Arboriculture (ISA) or equivelent credentials. ISA certified arborists are well trained in most tree care techniques. You can find an ISA certified arborist at this web site - https://www.treesaregood.org/.

Thank you. I appreciate the information!

Hello,

My Crape Myrtle developed black sooty mold, late last summer. It has put 
on its first few tiny leaves, but the black branches are still there. I 
have read all kinds of things to treat, but I'd appreciate your 
recommendation.

There are dianthus and pin cushion flowers planted at the edge of the 
flower bed, under it. I am afraid soaking the ground with a chemical 
might kill the flowers. I will cut off some of the blackest branches and 
scrub the tree as best I can. Does neem oil kill the insects?

Any guidance would be appreciated.

Thank you,

Nancy Tiernan

Sorry for the slow reply. There is a good chance you have crapemyrtle bark scale, an insect that covers itself with a white, cottony, waxy material and sucks on the plant juices. The black sooty mold is not the real problem (mold growing on the sticky sugary residue from the insect secretions), but the stress the insect puts on the plant as it sucks the juices from the plant.  Aphids also suck on plant juices which can result in the black sooty mold too, but usually it isn't as heavy. Getting rid of bark scale is a little trickier. Usually, it takes several management approaches including scrubbing off the scale insect and using systemic and contact insecticides. The concern using the systemic insecticides is not that it will harm surrounding plants, but that it gets in the flowers and can affect pollinators that visit the flowers. Systemic insecticides should be applied at the end of the growing season after the plant has flowered. This way, by the time the plant flowers again the following season, most of the insecticide has dissipated from the plant. Neem oil will help control the crawlers, immatures looking for a place to set up shop, but will not control them once the waxy coating has been developed.

Attached is an information sheet to help you with your management decisions.

You are very kind to answer my questions. I appreciate the information very much!

Sincere thanks,

Nancy