Biological Control of Colletotrichum spp. of Pepper (Piper nigrum L.) using Indigenous Bacterial Isolates from Soil Rhizosphere

Yap, Chin Ann (2017) Biological Control of Colletotrichum spp. of Pepper (Piper nigrum L.) using Indigenous Bacterial Isolates from Soil Rhizosphere. PhD thesis, UNIMAS.

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Abstract

Anthracnose caused by Colletotrichum gloeosporioides is a serious disease of black pepper. Yield losses attributed to the infliction of anthracnose disease on young spike and immature berries had been reported to be about 50% in serious case. Different approaches have been used to control this disease. One of the alternative approaches is through biological control. Colletotrichum gloeosporioides is able to infect and colonize detached pepper leaves and berries and develop infection symptoms 10 days after inoculation. Inoculation on wounded young leaves from Kuching variety with conidial suspension from 15 day olds cultures were the optimal condition for infection in ex vivo assay. The detached leaf inoculation method has proven to be useful for screening bacterial strains as biological control agents of pepper anthracnose. Five indigenous bacterial isolates namely B. subtilis, B. vallismortis, B. amyloliquefaciens and 2 B. atrophoues isolated from soil rhizosphere shown positive results against anthracnose disease caused by C. gloeosporioides. The five (5) Bacillus spp. were effective inhibit the growth of 5 pyhtopathogenic fungi, where control mechanisms involved were through the secretion of protease and cellulase enzyme that are responsible for fungal cell wall hydrolysis.

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