Question
QUESTION: We live in western Wisconsin. We just pulled out a purple leaf sand cherry shrub.  It had a nasty slimy reddish area on the trunk and all the branches when cut had a reddish color within. We'd like to relace it with a mock orange.  Do we need to do anythng to the soil before planting?  I don't want that to happen again if we can avoid it.  My virburnum has some curly, shriveled leaves throughout with whitish spot on the underside. It is about ten years old. What is it and what can I do?  The mock orange has the same problem. Thanks so much for your help.

ANSWER: Lisa,

First the sand cherry, it was effected by a peach tree borer. This insect will feed on any citrus tree- plums, cherries and peaches. Replacing it with an oleander is a good idea- this insect will not go after this plant. There will be no special preparation needed for the change.

The white spots on the oleander and viburnum could be cushion scale. I would recommend using a light rate of horticultural oil on the under sides of the leaves to control these insects.

Good luck,
Ed Gulliksen

---------- FOLLOW-UP ----------

QUESTION: We have a crab apple tree about ten to twelve feet away from where the sand cherry was.  Should I be concerned the crab apple will be affected by the peach tree borer? Is there something I should do for the crab apple in the way of prevention?  At this time the crab apple appears to be quite healthy.  I know the sand cherry had been sick for at least two years.

Thanks so much for your help.  I really appreciate it.
Lisa

Answer
Lisa,

You are right to be concerned about this insect, it could infest the crabapple as well. I would recommend having it treated with micro-injections done by a tree care company. Since this insect lives inside the tree, there are very few things that can be sprayed on the trunk to prevent or control them.

Good luck,
Ed Gulliksen