dying plants

Asked September 5, 2016, 3:40 PM EDT

My brother has a cherry laurel that has been fine for many years. This year it is dying off quickly. (I have pictures of the entire bush, the stem on the dying part and one that still has green but can apparently attach 3 pictures total.) Right next to it is a crepe myrtle that has had trouble to past few years. Here is pictures of the leaves with what looks bugs and mold. This is a Severna Park neighborhood where a rash of very large trees are being cut down because...we were told....a fungus is killing them. My brother just had the tree that normally shades these other two plants taken down because this problem. Any chance to save the cherry and crepe myrtle? I have several other pictures, but, it seems I can only put 3 here....

Anne Arundel County Maryland

1 Response

Many fungal diseases and pests are host specific, so it is not likely that what you are seeing here is related to the trees in the neighborhood that needed to be removed.
The good news is that crapemyrtle only do well in full sun, so now that it is in less shade it should be happier if we can get it's other issues under control.
The crape myrtle has sucking insects called aphids on it. These insects suck plant juices, and then excrete a sticky 'honeydew' on the leaves below. On top of that grows a black 'sooty mold', which is what is all over the leaf surfaces. Have your brother put on gloves and smoosh what soft-bodied aphids that he can, and then shoot the plant with a good strong squirt from the hose. This will dislodge and kill a lot of them.
The cherry laurel has different issues going on. First off, the dead areas should be cut out. The tiny white spots on the trunk and limbs looks like a type of insect (again a sucking insect) called white prunicola scale.
You could use a soft brush and water to gently scrub some of them off.
Monitor/watch for more. You could use a dormant oil spray in the cold season, and/or insecticidal oil or soap sprays for what are termed 'crawlers' in June.
Beneficial insects can help to control these pests, so try to conserve them and don't use sprays which have a long term residual or broad kill.