May 15, 2008
(Red Deer, Alberta) – There’s a new bug in town, and it’s preying on Black and Manchurian Ash trees. The Cottony Ash Psyllid has been present in Alberta for the last few years and, while it has no natural enemies, Urban Forester Elaine Johnson with The City of Red Deer says that doesn’t mean we have to say goodbye to our ash trees.
City Parks staff are implementing practices to control the Psyllid and save Black and Manchurian Ash trees on City property, and Johnson urges property owners to protect their trees at the same time, and control the spread of this deadly pest.
“This is the time of year that property owners can manage the pest themselves and prevent further damage to their trees,” said Johnson. “Ash trees will begin to leaf out in the coming weeks. If trees are sprayed with an insecticidal soap just as the leaves are beginning to emerge, the Psyllid larvae will be affected.”
Psyllid larvae hatch and feed on the new leaves of the two ash varieties, Johnson explains. As soon as feeding begins, the damaged leaves begin to curl around the larvae, forming a protective barrier that is almost impossible to penetrate with insecticidal soap.
“We urge everyone to check for the presence of Psyllids before deciding to spray their ash trees,” said Johnson. “Psyllid larvae are so tiny that they are difficult to see with the naked eye, but you know you have a Psyllid problem if your Black or Manchurian Ash tree leaves were curled and wilted last year.”
If property owners miss this brief window of treatment, another option is to have ash trees injected with a chemical that will not harm the tree but will kill the larvae once they ingest it from the leaves. Tree injections may only be performed by a certified pesticide applicator, and should be performed before the end of June.
“The Psyllid hatches twice every year,” said Johnson. “Once the first generation has completed its life cycle at the end of June, the aphid-like adults will fly to other ash trees. The mature leaves on those trees will immediately curl to conceal the second generation of larvae, so the best defense in stopping the spread this season is to manage the first generation.”
Johnson estimates that healthy ash trees will withstand Psyllid attacks for three to four years before succumbing. She stresses the importance of regular watering.
“Watering is essential to the health of any tree that is under attack by pests,” Johnson said. “It can give a tree the strength to withstand attacks long enough for us to get the pest under control. Because we didn’t receive a large amount of precipitation over the winter, supplemental watering is important.”
The City is in the process of contracting a certified pesticide applicator to inject Black and Manchurian Ash trees on City property. The injections will begin in the next few weeks.
Property owners can purchase insecticidal soaps at local nurseries and landscaping companies. Those property owners interested in investigating tree injections may search the phrases “tree care” or “extermination and fumigation” in the Yellow Pages to find businesses that perform this function.
For more information about the Cottony Ash Psyllid, please see the attached Backgrounder, or call Parks staff at 403-342-8234.
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For more information, please contact:
Elaine Johnson
Urban Forester
The City of Red Deer
403-342-8344
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