Common Tree Pests & Diseases
	Common Tree Pests & Diseases
	Black Knot Fungus
	Elm Scale
	Bronze Leaf Disease (BLD)
	Cottony Ash Psyllid
	Yellow-Headed Spruce Sawfly Outbreak
	Ash Leaf-Cone Roller
	Fire Blight
	Seasonal Spike of Aphids
	Dutch Elm Disease

Ash Leaf-Cone Roller

Over the past three seasons a new insect pest has become established in The City of Calgary. The insect is a moth and it is a pest on ornamental ash trees, principally Green and Manchurian Ash.

Early Stages

The early stages of the caterpillar feed within the leaf tissue. As the caterpillar grows, it emerges from the leaf, migrates to a new leaf, and rolls the leaf into a characteristic cone shape. The larva will continue to feed within this enclosure until the pupal stage. Larvae feed until mid or late June and the adult moths will emerge from the leaf cone starting about mid-July.

Damage to Tree

Although the insect can be quite prevalent on individual trees, the damage is minor and does not interfere with overall tree health. The rolled leaves remain attached to the tree and actual leaf damage is minimal.

Control Measures

As damage to the tree is minimal, The City of Calgary does not undertake any direct control measures against this pest. Since the caterpillar stage is completely enclosed, an insecticide spray program is largely ineffective.

As well, since the moth's establishment in Edmonton in 1999 at least two small parasitic wasps are noted to be associated with it and causing significant mortality. Thus, any chemical spray program would be far more detrimental to these natural enemies than to the ash leaf-cone roller.

Also, The City of Calgary is collaborating with University of Alberta researchers on deploying attract-and-kill traps as a pest management tool against the adult moths. These traps will start to be set up in 2007.