Nasty infestation of scale - think Provado make a spray for these, otherwise wash of with mild soapy water and rub over with methylated spirits on a cloth.

thanks, i`d never heard of this before. am going to cut right back and try the mild soapy solution and meth spirit. can i just spray soapy solution on or do i need to wash off completely. thanks again great help

You need to wash, you may find it quite difficult to dislodge the little critters, in which case, an hour or so and a pack of cotton buds and a bottle of meths - dip bud in meths, touch on the scale insect.