Bacterial diseases of banana: detection, characterization, and control management

Abstract Banana growth and hence production is affected largely due to many biotic factors that include bacteria, fungi, viruses, aphids etc. Common bacterial wilt disease that affect banana is caused by Xanthomonas vasicola pv. musacearum (Xvm), Ralstonia solanacearum. Symptoms include progressive yellowing, wilting and blackening of leaves; yellow or brown vascular streaks throughout the plant; pockets of pale yellow bacterial ooze in airspaces within leaf bases; premature ripening and internal discoloration of fruits. Erwinia-associated diseases such as bacterial head rot or tip-over caused by Erwinia carotovora ssp. carotovora and E. chrysanthemi, bacterial rhizome and pseudostem wet rot caused by Dickeya paradisiaca formerly E. chrysanthemi pv. Paradisiacal are also reported in banana. Other bacterial diseases of less widespread importance include: bacterial wilt of abaca, Javanese vascular wilt and bacterial fingertip rot (probably caused by Ralstonia spp.) R. solanacearum is soil borne pathogen, very diverse in its species, and belongs to group of Ralstonia-species complex. The Biolog GEN III identification is used as the first step in identifying the isolates from infected plants. This technology classifies bacteria by ability of their cell to metabolise all major classes of biochemicals, in addition to determining other important physiological properties such as pH, salt, and lactic acid tolerance, reducing power, and chemical sensitivity. Due to their diversity in species and strains, suitable diagnostic procedure should be done to identify the pathogens accurately. Pathogen identification based on colony morphology or disease symptoms is difficult, time consuming and unreliable. Molecular diagnostic such as polymerase chain reaction using specific primer and the other diagnosis of pathogen is also possible by using bacteriophage due to its specificity to infective. Rapid detection and accurate identification of pathogens in plant are critical steps to prevent pathogens dissemination. Innovative agronomic practices could be employed to control/manage the diseases. Integration of cultural practices with sensitive and specific diagnostic tools, transgenic approaches and conventional breeding techniques may offer a more sustainable and environmental friendly approach to control and manage the bacterial diseases in banana.