Determination of powdery mildew causal pathogen of rockmelon in Malaysia and screening the potential endophytic microorganism to control the disease / Nurnadiah Safi’n
Powdery mildew is a common and serious disease attacks on greenhouse crops especially cucurbits. Fungal pathogens Podosphaera xanthii, Golovinomyces orontii and G. cichoracearum were generally reported as the causal agents of powdery mildew in cucurbits. In this study, it was found that G. cichorace...
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| Format: | Thesis |
| Language: | English |
| Published: |
2016
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| Subjects: | |
| Online Access: | https://ir.uitm.edu.my/id/eprint/98969/1/98969.pdf https://ir.uitm.edu.my/id/eprint/98969/ |
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| Summary: | Powdery mildew is a common and serious disease attacks on greenhouse crops especially cucurbits. Fungal pathogens Podosphaera xanthii, Golovinomyces orontii and G. cichoracearum were generally reported as the causal agents of powdery mildew in cucurbits. In this study, it was found that G. cichoracearum is the pathogen of powdery mildew on rock melon in Malaysia. The germ tube of this pathogen emerges laterally with a clubbed germ tube. The conidia are oval to ellipsoid shape with two to eight conidia per chain. Based on the three establishment inoculation methods conducted, it was found that detached entire leaf method is the best suit method to preserve the inoculum during the experiment especially to measure the severity index of powdery mildew. It is convenient, practical and easy to handle as well as able to maintain turgidity of the leaves sample for a long time compared to leaf disc method. Thus, this study on understanding powdery mildew pathogen could lead to an effective management strategy to control the disease. Lack of knowledge on the pathogen itself consequently caused misleads to make a wise decision for controlling the disease. Nowadays, people tend to switch from chemical control to biological control due to their awareness of using more environmentally safe products and fungicide resistance problem. Two methods of isolation were conducted via serial dilution by crushing and centrifuging the asymptomatic leaves. Screening process was conducted on dual culture test and detached leaf. The most promising bacterial isolate was identified as Pseudomonas aeruginosa through the morphology, microscopic characteristics and biochemical tests. This negative rod bacterium showed the highest PIRG value of 78% against tested phytopathogenic fungi which could promising as potential biocontrol agent against G. cichoracearum. Pseudomonas aeruginosa is always been reported by many reports on its potential and effectiveness as the biological control agent. The result showed that this biological control agent has a big potential to control the disease. The use of biological control could reduce the application of chemical fungicides which are not environmental friendly and health concern. |
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