MAY 23, 2022 - BIOLOGICAL CONTROL AGENT REDUCES THE SPREAD OF SIAM WEED

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More than 300 stem-galling flies, or Cecidochares Connexa, have been released by the Cassowary Coast Regional Council in the Munro Plains area to combat the spread of the notorious Siam Weed (Chromolaena Odorata).

The stem-galling fly is the first to be released within Australia to combat Siam weed. The gall-fly combats the invasive weed by stunting the growth, reducing flowering and stopping the plant from seeding.

Environment portfolio holder, Councillor Jeff Baines said Siam weed, commonly in the Tully, Murray Upper and Johnstone catchment areas, is one of Australia’s most invasive weeds which smothers native plants and can poison livestock.

“Since 2018, Council has been working with the Department of Agriculture and Fisheries’ (DAF) Tropical Weeds Research Centre to release over 7,000 stem-galling flies into Siam Weed infestations at 44 sites across the Cassowary Coast.

“Nyleta Hill has been one of these release sites and monitoring shows plant gall numbers increase over the years and the flies spread to new Siam weed areas, which is a positive outcome for long-term weed control methods.

“Within the new site, landholders should expect to see gall development within 21 days of release, with a completed life cycle of the stem-galling fly taking up to 65 days.

“Whilst the stem-galling fly does not eradicate the weed fully, it has proven to successfully reduce and minimise the spread of the weed.

“In addition to the release of the stem-galling fly, Cassowary Coast Regional Council has recently undertaken roadside control of Siam weed to help residents, neighbouring council areas, and those further afield, to manage Siam weed,” said Councillor Baines.

Council and DAF will continue to monitor the flies and expect to see a positive result for the landholders at Munro Hill and its surrounds.

For further information please call Council on 1300 763 903 or via email at enquiries@cassowarycoast.qld.gov.au.