Bacterial Diseases of Bananas and Enset: Current State of Knowledge and Integrated Approaches Toward Sustainable Management

Abstract

Bacterial diseases of bananas and enset have not received, until recently, an equal amount of attention compared to other major threats to banana production such as the fungal diseases black leaf streak (Mycosphaerella fijiensis) and Fusarium wilt (Fusarium oxysporum f. sp. cubense). However, bacteria cause significant impacts on bananas globally and management practices are not always well known or adopted by farmers. Bacterial diseases in bananas and enset can be divided into three groups: (1) Ralstonia-associated diseases (Moko/Bugtok disease caused by Ralstonia solanacearum and banana blood disease caused by R. syzygii subsp. celebesensis); (2) Xanthomonas wilt of banana and enset, caused by Xanthomonas campestris pv. musacearum and (3) Erwinia-associated diseases (bacterial head rot or tip-over disease Erwinia carotovora ssp. carotovora and E. chrysanthemi), bacterial rhizome and pseudostem wet rot (Dickeya paradisiaca formerly E. chrysanthemi pv. paradisiaca). Other bacterial diseases of less widespread importance include: bacterial wilt of abaca, Javanese vascular wilt and bacterial fingertip rot (probably caused by Ralstonia spp., unconfirmed). This review describes global distribution, symptoms, pathogenic diversity, epidemiology and the state of the art for sustainable disease management of the major bacterial wilts currently affecting banana and enset.

Risks Posed by Intercrops and Weeds as Alternative Hosts to Xanthomonas campestris pv. musacearum in Banana Fields

“…The ABB types, in addition to attracting many insect vectors, have floral bracts and neuter flowers that readily fall off leaving open fresh wounds on the rachis/flower stalk that are easily colonized by bacteria accidentally deposited by foraging insects (Blomme et al, 2014, 2017a). XW incidence also declined with increasing number of banana cultivars on farm.…”

“…Data was also collected on other potential factors that could influence XW presence and incidence, and these included: presence of banana cultivars with ABB genome, the diversity of banana cultivars and presence of agroforestry trees. Banana cultivars with ABB genome are highily susceptible to insect-mediated XW infections (Tripathi and Tripathi, 2009; Blomme et al, 2017a) whereas, a high diversity of banana cultivars and presence of agroforestry trees were anticipated to cause a dilution effect and reduce insect vector access to the susceptible ABB banana types. XW management practices also play a crucial role in influencing disease presence and incidence on farm.…”

“…In banana, R. syzygii subsp. celebesensis strains that cause banana blood disease, a wilt of banana, is associated with some Heliconia species (Elphinstone, 2005; Blomme et al, 2017a). Ralstonia solanacearum that causes Moko/Bugtok wilt in banana has a wide host range (Belalcazar et al, 2004) and was also isolated from Heliconia species in the Coto valley virgin forests of southwest Costa Rica, leading to the suggestion that Moko could have originally been endemic in these rainforests (Sequeira and Averre, 1961).…”

Mechanistic insights into host adaptation, virulence and epidemiology of the phytopathogenXanthomonas

“…It was found that stingless bees and fruit flies carry high bacterial inoculum of Xvm when isolated from infected fields (Tinzaara et al 2006) and that floral parts are usually the initial inoculation point of the bacteria (Ocimati et al 2012;Rutikanga et al 2015). Following these observations, floral debudding is now commonly practiced in banana to prevent pathogen infection through any insect vector (Blomme et al 2017). It should be noted that while insect infection is very likely linked to Xvm dispersal, direct vector-mediated plant-toplant transmission has yet to be experimentally verified.…”

Hot water immersion disinfests enset (Ensete ventricosum) suckers from the enset root mealybug Cataenococcus ensete Williams and Matile-Ferrero

“…Author(s) agree that this article remain permanently open access under the terms of the Creative Commons Attribution License 4.0 International License enset cultivation since several decades and is considered the most important biotic constraint (Castellani, 1939;Yirgou and Bradbury, 1968;Welde-Michael et al, 2008;Blomme et al, 2017).…”