Identifying cause of death in a holly bush after 40 years in present location
We do not accept pest or insect samples. We viewed your photos. The holly in the left photo looks dead. We cannot say why. It may be due to poor drainage, root issues, insects, etc. It looks like the holly in the right photo is subject to two sucking soft scale insects called Indian wax scale (on the stems) and cottony camellia scale (on the undersides of the leaves).
This is not a disease.
Here is our website and photos of the Indian wax scale scale and cottony camellia scale
The scale is hard to control and looks like you may have a heavy infestation. You should have a professional landscaper come out to treat with a systemic insecticide. This will control both scale insects. We cannot recommend pesticides across state lines.
Here is some information.
Indian wax scale - Light to moderate infestations may product honeydew and sooty mold. Heavy infestations may cause early leaf yellowing and premature leaf drop.
Look on twigs and small branches for all wax scale stages. Crawlers begin hatching in mid June. Beginning in mid June pull off female wax scales every 1- 2 weeks and examine them to determine egg hatch usually mid July in MD. Infested twigs and branches must be thoroughly sprayed with a labeled insecticide after egg hatch usually the last two weeks of July to kill crawlers. Systemic insecticides applied through the soil after bloom will also control this pest.