Urocystis cepulae (onion smut) in South Australia

Publication Date

Fri, 11 Jun 2021, 02:19

Last Updated

June 11, 2021, 2:19 a.m.

Report Number

AUS-102/1

Country

Australia

Pest Id

Urocystis cepulae - (UROCCE)

Report Status

Final

Hosts

Very finite host range with susceptible hosts known only from the Allium genus. Onions are most susceptible, though infection is reported to a lesser extent in other key Allium crops such as shallots, chives and leeks. In Australia, onion smut has only ever been reported on onion.

Pest Status (ISPM 8 - 2021)

• Present: not widely distributed and under official control

Geographical Distribution

South Australia

Summary

In late September 2019, onion smut was detected on an onion crop on a property in Wall Flat in South Australia. In September 2020, onion smut was detected on an onion crop on a second property. Following this detection, the decision was made that onion smut is not eradicable from Australia.

Synonyms: Tuburcinia cepulae (Frost) Liro; Urocystis colchici var. cepulae (Schltdl.) Rabenh. Cooke; Urocystis magica Pass.

Danger

Urocystis cepulae occurs as distinctive narrow elongated dark streaks, usually on the cotyledon or first true leaf, which become thickened. The streaks are evidence of an infection that initially affects the internal leaf tissue and later bursts through the epidermal tissues and releases masses of dark-brown powdery spores. Seedling onions usually die within a few weeks and plant populations are reduced. Plant populations are also reduced by pre-emergence seedling death from smut. Diseased plants that survive are often distorted, develop blisters on the green leaf tissue and remain stunted. Yields are reduced. Mature bulbs may, less commonly, have dark pustules. Onion smut is only known to be present on two properties in South Australia and as of 16 December 2020, onion smut is no longer under official control in South Australia. Onion smut is under regional official control in Western Australia, New South Wales, Victoria and Tasmania.

Contact for info

Australian Chief Plant Protection Officer Australian Government Department of Agriculture GPO Box 858 Canberra ACT 2601 [email protected]

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