Sad to say if they are scale insects they have become immune to most of the
systemic insecticides.
I had n infestation on a Queensland Palm and had some sucess thoroughly
washing with soap solution. This cleared a lot of them off and I set about
the survivors with sugical spirit and a fine camel hair brush.
Afer two weeks I used the weapon of last resort Malathion , which is not
nice, but it worked.
Protect yourself and the plant whilst you do the deed.

wrote in message
...
My mallow has a lot of yellow leaves. Looking at the back of the leaves I
discovered that they were covered
with scale insect. The little blighters craftily hide behind the
leaves.Any
suggestions as to what I should use to get rid of them ?
Tom Atkinson