BIOSECURITY SA has warned garden nurseries, landholders and gardeners of the need for ongoing vigilance this summer for the degenerative plant disease Myrtle rust.
Myrtle rust, which infects the Myrtaceae family of plants including many Australian native species, is prevalent in Australia’s eastern seaboard states and has been recently discovered in Victoria.
Biosecurity SA’s Manager of Plant & Food Standards, Geoff Raven, said that although Myrtle rust had not yet been found in South Australia, the threat of its spreading to our state – particularly during ‘ideal’ conditions of successive hot, humid nights – could not be ignored.
“The message for landholders, gardeners and nursery owners is simple – if you suspect Myrtle rust has been found, please report it to the Exotic Plant Pest Hotline on 1800 084 881,” Mr Raven said.
“It’s most important that if you do suspect Myrtle rust, do not touch or try to move infested plant material so as to avoid becoming contaminated and enabling it to spread.
“These types of rust affect commercial plant growing operations and native ecosystems.”
Mr Raven said the Nursery and Garden Industry Association of SA had advised the industry of the situation in Victoria and informed its members to be vigilant in complying with SA’s entry requirements for host material that may have been infected with the rust.
“Garden nurseries are considered to be the front line for the rust and Biosecurity SA’s Plant Health staff have been working with them to inform their members,” Mr Raven said.
“To manage the risk of accidental importation of infected material, movement controls are in place. All Myrtle rust host material entering SA from Victoria after 12.01am on Wednesday 11 January 2012 has had to comply with quarantine entry requirements specific to Myrtle rust in the SA plant quarantine standard, regulated under the Plant Health Act.
“While South Australia’s environmental conditions are generally considered unfavourable for the spread of Myrtle rust, current summer conditions in nurseries and many gardens are suitable for the development and maintenance of the disease, particularly on susceptible species and varieties.”
Myrtle rust produces lesions on young, actively growing leaves and shoots, besides on fruits and sepals. Leaves may become buckled or twisted as a result of infection. On turpentine and callistemon rust lesions are purple, with masses of bright yellow or orange-yellow spores. Occasionally, they may have dark brown spores. Severe rust disease in young trees may kill shoot tips, causing loss of leaders and a bushy habit.
Further information on Myrtle rust and how to identify and treat can be found on PIRSA’s website at: www.pir.sa.gov.au/ biosecuritysa/planthealth/emergen cy_plant_pests/myrtle_rust