Isolation and identification of fungi associated with leaf diseases of hevea brasiliensis

Nur Izzati, Binti Ghazali (2013) Isolation and identification of fungi associated with leaf diseases of hevea brasiliensis. [Final Year Project Report] (Unpublished)

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Abstract

Hevea brasiliensis is the second most important commodity in Malaysia after oil palm. Disease infection on the plant may decrease the production of latex. This study was conducted to identify diseases which can be seen on leaves and to identify fungi associated with the diseases. Ten types of diseases had been found. The most common fungus isolated was Colletotrichum sp. which associated with brown lesion, brown spot and black spot. The other fungi isolated were Apergillus niger, Botyodiplodia theobromae, Curvularia sp., Pestalotiopsis sp., Phomopsis sp. and an unknown sp. Physiological tests were conducted to look at the growth of the fungi isolated at different pH, temperature and light condition. A. niger grew optimumly at temperature 25°C to 30°C and at pH 8 to pH 9. B. theobromea grew optimumly at temperature 20°C to 25°C and at pH5 to pH 9. Colletotrichum sp. grew optimum}y at temperature 20°C to 30°C and at pH 6 to pH 7, Curvularia sp. grew well at 20°C to 30°C and at pH 3 to pH 5, Pestalotiopsis sp. growth was between 25°C to 30°C and at pH 3 to pH 5, Phomopsis sp. grew well at 25°C to 35°C and at pH 4 to pH 7 and Unknown sp. grew well at 20°C and at pH 4 to pH 7. The light conditions had significant effect to fungi growth. Mycelia growth for B. theobromea, Phomopsis sp. and unknown sp. was fast the growth rate of fungi, Curvularia sp. grew well at dark condition but light condition not influenced growth of A. niger, Colletotrichum sp. and Pestalotiopsis sp. The most effective fungus and bacterium tested to inhibit growth of Colletotrichum were Gliocladium sp. and Pseudomonas aeruginosa respectively according to the inhibition. Pathogenicity test using the Colletotrichum sp. on leaves of rubber give positive infection symptoms. Further study on the diseases of rubber tree in Malaysia should be carried out as a proper documentation on pathogen will resulting in the good prevention and treatment measures in future.

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