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Dutch Elm Disease-Left Panel
(Click on the picture for larger view)
(Unless otherwise indicated, photos by Don of www.WascanaPark.com)
Dutch Elm disease is a fungus spread by Elm
Bark Beetles. These beetles feed on the inner
bark of elm trees. If a beetle is contaminated
with Dutch Elm Disease spores, it may transmit
the disease to the tree.
The fungus grows in the vascular system of
the tree causing death of part or all of the tree.
By mid June, the beetles seek out recently dead
branches of elm trees or elm firewood to lay their
eggs. The eggs are laid in the inner bark which
provides a moist incubation site. They cannot use
healthy elms for this purpose because the flow of
the sap is too great.
The eggs hatch, pass through a larval/pupae stage
and emerge as adults, flying to the base of a healthy
elm in late August to overwinter.
In early spring, overwintering Elm Bark Beetles
emerge from the base of the tree and crawl or
fly to healthy elm trees to feed.
(Information from the information panel)
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