Banana freckle

Have you seen banana freckle?

A suspected case of banana freckle has been detected on Cavendish bananas in the Northern Territory.

If you suspect banana freckle on your plants, report symptoms to Biosecurity Queensland on 13 25 23.

General information

Banana freckle was detected on Cavendish bananas in the Northern Territory in 2013. In response, a nationally cost shared Banana Freckle Eradication Program is in progress.

Banana freckle that can affect Cavendish bananas is not known to occur elsewhere in Australia.

If you suspect banana freckle on your plants, report symptoms to Biosecurity Queensland on 13 25 23

Overview

Cause The banana freckle detected on Cavendish in the Northern Territory is caused by Phyllosticta cavendishii. This species is exotic to Australia.
Other names

Phyllosticta cavendishii is sometimes called Cavendish competent banana freckle or Cavendish banana freckle.

A different species of banana freckle that is found in Queensland is caused by Phyllosticta maculata M.H. Wong and Crous. (Teleomorph Guignardia musae Racib. Syn Phyllosticta musae Yen.).

There are other organisms causing banana freckle overseas, for example Phyllosticta musarum (Cooke).

Description
Leaves and fruit:
  • Large and small spots (1-4mm) are found on leaves and fruit.
  • Have a sandpaper feel caused by the fungal structures protruding through the surface of the leaf.
  • Severe infection results in yellowing of the leaf, which withers and dies.
  • The disease may also cause blemishes on fruit.
Spots:
  • Dark brown to black in colour.
  • Small spots are less than 1mm in diameter and appear sooty and can run together to form streaks.
  • Larger spots are up to 4mm in diameter and can also appear as streaks.
  • Sometimes the centre of these larger spots are lighter in colour.
  • Spots can also appear on the midrib of the leaf and on the petioles.
Distribution

A nationally cost-shared eradication program is in progress to eradicate P. cavendishii in the Northern Territory. It is not known to occur elsewhere in Australia.

Phyllosticta musarum has not been detected in Australia.

An endemic species of banana freckle that is present in Australia is caused by Phyllosticta maculata. It is widespread and causes minor disease. In Queensland, it can be found on islands in the Torres Strait, on Cape York Peninsula and far north Queensland. Itis found most often on cooking bananas such as Bluggoe and Blue Java.

Freckle symptoms also occur on cooking bananas in Papua New Guinea, other areas of South East Asia, and India, the Caribbean and central Africa. In the Philippines and Taiwan, India, Borneo and Java.

Lifecycle

The freckle spots contain fungal fruiting bodies (perithecia and pycnidia). When it rains or following heavy dew, ascospores and conidia are released. Conidia in particular play an important part in the infection cycle. They can be spread by raindrops or water splash onto or across leaves and fruit. The spores germinate, penetrating the host and multiply within and between cells, creating new spots or lesions in the superficial layers of the host plant tissue.

The incubation period can be as little as 20 days in hot humid weather.

Streaks of freckle spots or overlapping infection spots can result from water loaded with spores running off or from repeated daily infection points (Meredith 1968, and Chuang 1984, cited in Jones 2000).

Crops affected
  • Banana
Hosts

Banana freckle is only known to infect banana plants.

Phyllosticta cavendishii is capable of infecting Cavendish and Ladyfinger banana plant varieties.

Impacts

Banana freckle decreases the health and productivity of infected plants by reducing the amount of healthy leaf area. Blemished fruit may not be suitable to market commercially.

Spread

Banana freckle is a 'wet spore' organism. It generally moves short distances through droplet splash. Banana freckle may also be spread through the movement of infected plant material and fruit.

Risk period Banana freckle can affect a banana plant at all stages of the production cycle.

Monitoring and action

Inspect your plants regularly for the presence of exotic pests and diseases. A closely related species, Phyllosticta maculata, causes similar symptoms on bananas, and is present in Australia. Since both P. cavendishii and P. maculata can be found on lady finger bananas, diagnostic testing is required tell them apart.

Report any symptoms of banana freckle to Biosecurity Queensland immediately on 13 25 23.

Control Some chemical treatments used to control another banana disease - yellow Sigatoka, may help control freckle. Mineral oil alone is not considered effective. Using a plastic bag cover over the bunch may be the most long-term cost-saving control for freckle.

Quarantine restrictions

Movement of banana fruit and plant material from the Northern Territory into Queensland is prohibited.

Restrictions apply to the movement of plant material or related items such as soil and equipment into and within Queensland.

Under the Biosecurity Act 2014, Freckle disease of banana (other than P. maculata) is prohibited matter in Queensland. Report symptoms without delay to Biosecurity Queensland on 13 25 23

 

Last updated 27 October 2017