38th Annual Meeting of the Society for Invertebrate Pathology

Among the major constraints to highland cooking banana in Uganda is the high level of nematodes and banana weevils. Naturally-occurring endophytes such as Fusarium oxysporum are antagonistic to these pests. Control by endophytic F. oxysporum can be greatly enhanced when artificially inoculated. We contrasted inoculation through root and corm dipping using a spore suspension with inoculation using a solid substrate. The use of a solid substrate inoculation method resulted in the highest root colonization. No differences among inoculation methods were observed with respect to corm colonization. Corms were colonized to a higher extent than roots but hyphal density in the roots was higher than in the corms. Root persistence of endophytic F. oxysporum was sustained for up to 25 weeks. In contrast, corm tissue colonization decreased rapidly. Although corms are initially colonized to a higher extent than roots following inoculation, hyphal density is much lower, presumably allowing other microbes to occupy available niches and explaining the difference in persistence between roots and corms. When tissue culture plants are inoculated with Beauveria bassiana using a root and corm dip method, percentage colonization was 47.3% after four weeks, demonstrating that B. bassiana can be used as an artificial endophyte in banana.