Question
Hello ,
I have a large 10yr old acer and I have noticed , what look's like white mould/powder on the stem , what do I need to do to stop it .
Many many thank's ,
Donna .

Answer
Hi Donna, If the white, powdery substance on the stems is a thin, smooth coating, it is probably cuticular wax, a natural substance the plant produces to protect the stem. It is probably better to leave it alone. On the other hand, if the coating is bumpy and not particularly homogeneous, or it moves on its own, it may be something else (possibly an insect).  kathy