Detection of Phyllosticta cavendishii in Northern Territory

Publication Date
Fri, 04 Oct 2013, 02:00
Last Updated
June 30, 2015, 8:30 a.m.
Report Number
AUS-59/2
Country
Australia
Pest Id
Phyllosticta cavendishii - (PHYSCA)
Report Status
Preliminary
Hosts
Musa: Banana—Cavendish cultivar
Pest Status
  • Present: only in some areas
  • Present: under eradication
Geographical Distribution
The disease has been identified on plants in two localities in the Northern Territory, just south of Darwin
Summary

Freckle disease is an economically important disease of banana in many countries. The pathogen causes freckle spots on infested leaves that appear as either discrete brownish-black spots or in the form of circular or streaking lesions on leaf surfaces or along leaf veins. On fruit, reddish-brown to black freckle spots are surrounded by dark green, water-soaked halos and in severely infested plants, dense aggregation of spots may completely cover banana fruit at harvest, adversely affecting the cosmetic value of the fruit. In addition to causing significant yield reduction, diseased fruit is unsuitable for export. Recent taxonomic studies based on morphological structures and molecular data on a global collection of specimens have shown that the causal agent of banana freckle are three different, but closely related species of Phyllosticta: P. musarum, P. maculata and P. cavendishii. Symptoms cannot be used to distinguish the three species. Definitive identification relies on examination of morphological structures such as fruiting bodies and spores obtained from lesions or fungal cultures.

Danger
Banana-infecting Phyllosticta is a widely distributed group of species and known to occur in north Queensland since 1979 and the Northern Territory since 1991, but not on Cavendish banana cultivars. DNA finger printing has identified the host as Cavendish cultivar. It is possible that the infestation is either a new incursion from outside of Australia of a Phyllosticta cavendishii strain that infects the Cavendish or that it is the new expression of a host-specific race of P. cavendishii that has been present in Australia and has mutated to infect the Cavendish cultivar. Eradication is currently being carried out by removing and destroying all infested plant material. A Quarantine notice has been served on all infested premises to ensure there is no movement of plant material, fruit or equipment off these premises. Australia currently does not export bananas.
Contact for info
Australian Chief Plant Protection Officer Australian Government Department of Agriculture, GPO Box 858 Canberra ACT 2601 Australia ippc.contactpoint@agriculture.gov.au
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