There are three major threats to the health of Australia's elm trees. Two of them, The Elm Leaf Beetle and the Elm Bark Beetle, already exist in Victoria. The third and most serious, Dutch Elm Disease, is not far away.

• Elm Leaf Beetle (Pyrrhalta luteola)
  Our first battle is to control the spread of the Elm Leaf Beetle, which was discovered on the Mornington Peninsula in 1989 and has now spread to many other areas, including central and suburban Melbourne. The beetle and its caterpillars eat only elm leaves. They can totally destroy the tree canopy in one spring/summer season.

  Methods of control are available, both physical, biological and chemical, but the co-operation of the public is needed so these controls can be applied. Defoliation weakens the elms and creates dead branches. This brings us to:

• Elm Bark Beetle (Scolytus multistriatus)
  This small, European beetle was first officially discovered in Victoria in 1974. It feeds and breeds under the bark of injured and dying branches defoliated by the Elm Leaf Beetle or caused by drought or neglect.

  Unlike the Elm Leaf Beetle, the Elm Bark Beetle causes no serious damage to elms. However, it is the carrier of Dutch Elm Disease (DED) and would be a threat to the trees if (or when) the disease enters Australia.

• Dutch Elm Disease
  Should Dutch Elm Disease (DED) reach Australia, it will be the most serious threat to our elms.

  Except for places where a major effort has been made to save them (Brighton district in UK and Amsterdam in the Netherlands) elms have been devastated by DED in the Northern Hemisphere. New Zealand's elms became infected with DED in 1989.

  DED is caused by a fungus which prevents the flow of sap within the elm's vascular system; it can kill the tree within one season. The fungus spreads from tree to tree by means of the elm bark beetle, or by root grafts.

  Tight quarantine laws and vigilant officers are believed to have prevented the fungus entering Australia, but the risk of entry increased with the arrival of the fungus in Auckland, NZ. There, however, through good management the loss of the trees is in hundreds rather than thousands, but the risk of spreading remains indefinitely.

  The Elm Pests and Diseases Task Force has been set up to co-ordinate all activity about elms and to be responsible for implementing the contingency plan should DED reach our shores. But public participation is essential if all the threats to our elms are to be minimised.

  An excellent source of further information on DED is Steve Fitzgerald's Page at: http://www.netspace.net.au/~stephenf/

  While Greg Lefoe has written an article on Elm Leaf Beetle at: http://www.global-garden.com.au/burnley/mar00dte.htm