Photo 1. Close up of spots as in Photo 1, showing the spore masses of black leaf mould, Pseudocercospora fuligena, on the underside of the leaves.
Photo 2. Black leaf mould, Pseudocercospora fuligena, on the underside of tomato leaflets, showing the areas where spores are produced.
Photo 3. Dark brown or black mould growth ont he underside of the leaf caused by tomato black leaf mould, Pseudocercospora fuligena.
Photo 4. Black spots, yellowing and rapid dying of tomato leaves infected by black leaf mould, Pseudocercospora fuligena.
Black leaf mould, leaf spot, tomato leaf mould
Pseudocercospora fuligena. Previously, known as Cercospora fuligena.
Worldwide. In tropics. Asia, Africa, North (restricted) and South America, the Caribbean (restricted), Oceania. It is recorded from Australia, Cook Islands, New Caledonia, Palau, Papua New Guinea, Solomon Islands, and Vanuatu.
Tomato, capsicum, chilli, and eggplant.
The disease starts on the older leaves and spreads upwards. The first signs are irregular yellow patches with indistinct margins on both sides of the leaves (Photo 1). Those on the lower surface develop a brown or dark brown mould containing the spores (Photos 2&3). The spots join together and the leaflets rapidly dry, die and the leaves hang down (Photos 4&5). Later, they fall off. There are no symptoms on the fruit.
The spores are spread by wind-blown rain, and if windy wet weather continues for a few days, spread is fast and plants defoliate rapidly.
The source of the fungus is from other infected crops, the remains of the previous crop and, perhaps, other host species. The fungus is not seed borne.
The fungus causes plants to lose their leaves. If infection occurs before the fruit has developed, yields are low. This is an important disease on tomato in Solomon Islands.
Look for the disease on the bottom leaves. Look for the yellow spots on the upper leaf surface, and the brown mould-like spore masses, mostly on the under surface of the older leaves.
Note, there is another disease that has similar symptoms. It is called tomato leaf mould, caused by the fungus, Passalora fulva (see Fact Sheet no. 76). This fungus and Pseudocercospora fuligena can only be distinguished by looking at their spores under a microscope.
Cultural control is important. The following should be done:
There are varietal differences in susceptibility to Pseudocercospora fuligena, and trials are being done in Solomon Islands testing lines from AVRDC (The World Vegetable Center, Taiwan).
Warm wet conditions in Pacific island countries favour the disease such that fungicides are needed to give adequate control. The products to use are chlorothalonil, copper oxychloride or mancozeb. Treatment should start when the first flowers appear, and continue at 10-14 days intervals until 3-4 weeks before last harvest. It is important to spray both sides of the leaves.
AUTHORS Helen Tsatsia & Grahame Jackson
Photo 1&2 Jaw-Fen Wang, AVRDC, The World Vegetable Center, Taiwan. Photo 5 McKenzie E (2013) Pseudocercospora fuligena. PaDIL - (http://www.padil.gov.au).
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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