Ballarat has one of the most significant populations of elm trees in the world and many of these trees are in private property. Most Elm trees within the City of Ballarat now have Elm Leaf beetle on them. The beetle only attacks elm trees and no other species.
They are about 6mm long, yellow to olive in colour with black stripes and lay clusters of small yellow eggs on the underside of the elm leaves. There are normally 2 life cycles per year however in warmer, drier years such as we are currently experiencing a 3rd cycle is possible. The beetle damage the tree by creating small “shot” holes throughout the leaves and the larvae skeletonise the leaves. Although this does not normally kill the tree, prolonged severe attacks over a number of years may result in tree deaths.
The City of Ballarat has an ongoing treatment program using a contractor who uses either soil injection or direct trunk injection of chemical to treat the beetle. Although it is most likely we will never eradicate the beetle we can try to manage its numbers. The trees are closely monitored by our arboriculture team for performance.
Alternative non chemical treatments such as predatory insects and naturally occurring bacteria are also being investigated by our arboriculture team and may be used once they become available. The City of Ballarat is responsible for elms on public land but can provide advice for private elm owners to assist in controlling elm leaf beetle e.g. ELB identification and contact details for pest contractors. To speak with a member of the arboriculture team please contact customer service on 5320 5500.