Tuesday, July 7, 2009

Cottony Psyllid - aka dead ash trees- Revised

Listeners to CBC know a lady phoned in about her  Green ash tree  last week - it had not leafed out properly and she was worried about it. Just in case I didn't give enough information about this new pest, the  Cottony Pysllid, I thought I should add a quick blog. Dr. Ken Fry - Entomology instructor at Olds College reminds me this pest is only a problem on Manchurian and Black ash - not on green ash. If a green ash is suffering it is likely from ash plant bug (with noticeable black frass on leaves) or wooly ash aphid with similar curled leaves to the cottony psylllid. If the caller is certain she has a Green Ash that is likely the problem.

If the tree is a Manchurian or Black ash it may have perfectly good leaves one year and be almost dead  the next year but I have suffered from this same problem and my tree is now dead completely and removed. There are no organic cures for this insect yet, but some of the larger tree care companies are now treating it. Again, Dr. Fry says "systemic insecticides injected into the tree have proven to be very effective against the cottony psyllid".

Everything  you need to know about this new pest is at the following web page:

http://www.landscape-alberta.com/pdf/Cottony_Psyllid_JUNE_%202006.pdf

1 comment:

kfry said...

Just a note for clarification: The cottony psyllid does not attack green ash, it only feeds on black or Manchurian ash. If a green ash is suffering it may be from ash plant bug (noticable black frass on leaves)or woolly ash aphid (curled leaves similar to cottony psyllid).
Systemic insecticides injectedc into the tree have proven to be very effective against the cottony psyllid.

Sincerely,
Ken Fry