Native elm bark beetle
New Brunswick, Nova Scotia, Prince Edward Island, Quebec, Ontario, Manitoba, Saskatchewan
Damage, symptoms and biologyThe first sign of attack by the native elm bark beetle is red sawdust on the bark, appearing in the fall or in early spring; this sawdust is present near the adults’ entrance or exit holes.
The adult excavates a gallery that leaves a V-shaped impression on either side of the entrance hole. These galleries are horizontal and run across the wood grain. These two distinguishing features can be used to identify the native elm bark beetle.
The young larvae that hatched from eggs laid on either side of a gallery excavated by a female in turn bore their own tunnels perpendicular to that of the adult. This insect is a vector of Dutch elm disease. Adults that emerge from infected elms carry the spores to the next healthy trees on which they feed. After feeding, the adults return to weakened or injured trees and lay their eggs on the trunk.
Native elm bark beetles overwinter mainly as adults in galleries beneath the bark of healthy trees. However, the insect can overwinter in any stage, except that of egg.
Life cycle (East of the Rockies)
Other informationAs a species indigenous to North America and a vector of the Dutch elm disease fungi, the native elm bark beetle plays a leading role in the transmission of this disease, which wiped out the American elm population in eastern North America. The insect is monitored by many municipalities and some municipalities apply preventive measures under an integrated pest control program with the aim of preventing the spread of this insect and hence the disease. Appropriate measures are listed below.
- It is important to ensure proper sanitation in areas with healthy elms in order to reduce potential breeding sites for bark beetles.
- cut down and burn or bury elms that show symptoms of Dutch elm disease;
- prune all material likely to be used for breeding and burn or bury the debris;
- never leave felled or injured elms near healthy ones; remove the bark from stumps and newly cut logs that are to be used as firewood;
- burn or bury all unstripped wood prior to May 1.
The following practices are recommended:
Dutch elm disease is an exotic disease that comes under the authority of the quarantine acts and regulations administered by the Canadian Food Inspection Agency. Wood infected with this disease must not be transported to regions where the disease is not present.
Canadian Forest Service Publications
Diet and feeding behaviour
: Feeds on phloem.
- Borer: Bores into and feeds on the woody and non-woody portions of plants.
Information on host(s)
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