Banana Deightoniella leaf & fruit spot, banana leaf blotch.
Deightoniella torulosa. Previously known as Brachysporium torulosum.
Worldwide. Asia, Africa, South and Central America, Oceania. It is recorded from Australia, Cook Islands, Federated states of Micronesia, French Polynesia, Kiribati, Marshall Islands, New Zealand, Palau, Papua New Guinea, Tokelau, Tuvalu, Samoa, and Solomon Islands.
Banana, and relatives in the banana family (Musaceae), e.g., Musa textilis, Ensete ventricosum, and Heliconia, Strelitzia, and Costus species.
Reported as a leaf blotch, and on the fruit spots and a tip rot. On the leaves, it causes oval, tan spots with a black border, usually on the older leaves (Photo 1). On the fruit, sunken dark brown or black spots, 2-4 mm wide, surrounded by a dark green halo. Spotting of the fruit is greatest towards the tips of the fingers.The fungus does not produce spores on the fruit.
In the Philippines, the fungus causes a rot of the pseudostem on manila hemp (Musa textilis).
Spread is by spores produced in large numbers on dead leaves during rains and released into the air. The fungus also attacks the flower parts and these are a source of spores, too.
A minor disease, on older leave, unlikely to cause their premature death and reduce fruit yield in a well-managed plantation where other, more serious diseases, are under control.
Look for the oval tan spots on the older leaves and sunken dark spots on the fruit, 2-4 mm wide.
It is unlikely that specific control measures will be necessary for Deightoniella leaf & fruit leaf spot in a well-management commercial plantation. The fungicides used to control black Sigatoka will reduce the disease. The following are used routinely:
(i) Protectant fungicides (these stay on the surface of plants) -
Mancozeb can be used together with oil or an oil/water emulsion; chlorothalonil is used in water. If black Sigatoka was not present, these would be sufficient to control speckle diseases. If black Sigatoka was present, then systemic fungicides might be used (see Fact Sheet no. 002):
(ii) Systemic fungicides (these move inside the plants) -
If systemic fungicides are use, it is important to rotate the fungicides in the different groups to prevent the build-up of resistant strains of the fungus. No more than two applications of the same systemic fungicide should be made before changing to another group. In drier times, mancozeb can be used alone. Note, it is important to add a sticker to any of the fungicides.
AUTHORS Grahame Jackson & Eric McKenzie
Information from Diseases of fruit crops in Australia (2009). Editors, Tony Cooke, Denis Persley, Susan House. CSIRO Publishing. Photo 1 (taken by Eric McKenzie), and used in this fact sheet, appeared previously in McKenzie E (2013) Deightoniella torulosa PaDIL - http://www.padil.gov.au. Photo 2 Tropical Banana Information Kit: Problem Solver. Queensland Governemnt. (http://era.daf.qld.gov.au/1656/6/5protrbn_part1.pdf).
Produced with support from the Australian Centre for International Agricultural Research under project PC/2010/090: Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production, implemented by the University of Queensland and the Secretariat of the Pacific Community.
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