horrid gubbo

on my cork bark elm. have brushed it off previously but as suspected it came back. can't see it in my small library of books. sorry for the blurry nature of the second picture:

Scale insect my friend. I have discovered plenty on my trees this year. Squish the beggars and look out for smaller ones as well.

will baddeley wrote:Scale insect my friend. I have discovered plenty on my trees this year. Squish the beggars and look out for smaller ones as well.

is that the only tactic? I can't see the bleeders. Is there any scale insect napalm I can frag them with?

Lime Sulphur at 7 to 10-1 on a cotton bud works well as does meths. I squish it with my fingers and remove as much as possible then use LS as above.

My Siberian Elm gets it every year and with either of the above I have never had a problem.

Mike

Look for a systemic insecticide with the active ingredient Imidacloprid. It is listed for scale.
Iris

Elms can play up when systemics are used - and is not recommended by many experts. Your tree though.

Mike