Source: SEAMEO BIOTROP's Research Grant | 2017
One of the problems in the cultivating satoimo taro is leaf blight disease caused by Phytophtora colocasiae. The pathogen is capable of producing spores that are ready to be released in water and spread through water splashes, usually it will increase during the rainy season. The decrease in taro tuber production caused by Phytophtora colocasiae attack can reach up to 50% causing high economic losses. The objectives of this research were to know the potential of various formulations in maintaining viability of selected endophytic bacteria from mangrove and their potency in suppressing the growth of Phytophtora colocasiae and to identity endophytic bacteria from selected mangrove plants through molecular technique.
The research method includes pathogen isolation, selected endophytic bacteria formulation, formulation stability test, application of formulation on plant and observation of disease occurrence and severity and identification of bacterial isolates molecularly. The research results showed that compost formulation has the best stability capacity compared to other formulations in maintaining viability of endophytic mangrove bacteria up to sixteen weeks. The study also found that mixture endophytic bacteria treatment is better than single isolate treatment.
The liquid formulation test showed that the severity and incidence of isolate A treatment was the best treatment which gave a disease severity suppression value up to 57% followed by ABC mixture bacteria treatment which suppressed disease severity up to 35%. In the test of dust/flour formulation and solid/compost formulation, the value of severity and incidence of ABC isolate treatment showed?? the best disease severity suppression with the lowest severity and disease occurrence of 20% (KeP and KjP dust/flour formulation) and 6.6% and 20% (KeP and KjP solid/compost formulations). It was also found that YA1K5-7 isolates in dust/flour formulation showed the highest plant height and root weight of 68.4 cm and 44.9 gr. While the isolates of BR1K5-4 in solid/compost formulation have the best fresh weight of 94.8 gr. In this study, ten selected isolates of mangrove endophytes have been identified by molecular technique as Bacterium NLAE-zl-H299, Providencia rettgeri, Providencia vermicola, Enterococcus faecalis, Bacillus amyloliquefaciens, Bacillus cereus, Bacillus thuringiensis. All of them has the ability to regulate plant growth and suppress the development of pathogen.
Keywords: Mangrove, Endophytic Bacteria, Phytophthora colocasiae, Plant Disease Control, Bacterial Formulation
Download full report