Trachysphaera fructigena is an oomycete affecting bananas and cacao trees. This oomycete is a weak plant pathogen that causes minor diseases in banana, coffee, and cocoa.[1]
| Trachysphaera fructigena | |
|---|---|
Scientific classification 
| |
| Domain: | Eukaryota |
| Clade: | Diaphoretickes |
| Clade: | SAR |
| Clade: | Stramenopiles |
| Phylum: | Oomycota |
| Order: | Peronosporales |
| Family: | Pythiaceae |
| Genus: | Trachysphaera |
| Species: | T. fructigena
|
| Binomial name | |
| Trachysphaera fructigena Tabor & Bunting, (1923)
| |
Hosts
editTrachysphaera fructigena primarily affects banana (cigar-end rot), coffee, and cocoa but is also associated with Mimusops elengi, M. commersoni, and avocado (Persea americana). It can also infect flowers and wounded fruit of Pyrus, Malus, Prunus, and Citrus species under artificial conditions.[2][3]
Signs and symptoms
editOn bananas, the oomycete causes cigar-end rot, forming ash-grey, wrinkled lesions at the flower end, which can progress to black necrosis and mummification during storage or transport. On cocoa, it infects wounded pods, creating brown spreading lesions with dense, coarse-textured conidial masses that turn pinkish-brown.[2] On Liberica coffee, it is linked to the rot of ripe berries. Symptoms of T. fructigena on fruits are easily identified, making it unlikely for infected fruit to enter trade or spread the pathogen. While distinguishing the pathogens causing cigar-end rot requires expertise, the symptoms of cigar-end rot on banana fruit are distinct and unlikely to be mistaken for other banana fruit rots.[4] Only the fruit and flowers are known to carry the pathogen during trade, while other plant parts are not considered carriers.[1]
Morphology
editThis oomycete produces non-septate, coarse hyphae that spread rapidly through intercellular spaces, with smaller branches penetrating host cell walls, killing the cells and discoloring their contents. Once established in host tissues, the oomycete forms conidia. Hyphae accumulate beneath the epidermis, where dense conidiophores form and rupture the epidermal layer. Conidiophores vary, ranging from simple structures with single conidia to complex forms with terminal vesicles and whorls of conidia or lateral fertile branches. The oomycete produces thick-walled conidia in fruit cavities, resembling chlamydospores, though their germination remains unobserved. Regular conidia germinate readily in water or nutrients, forming mycelium and conidia, allowing easy cultivation and infection experiments. Sexual reproduction involves oogonia characterized by irregular sac-like outgrowths and amphigynous antheridia surrounding their stalks.[2][5]
Prevention and control
editCultural practices, such as bagging in bananas and inflorescence binding in plantains, have consistently proven effective in reducing the percentage of infected bunches, even under conditions favorable to disease development.[6][7] Bagging is also widely implemented to protect fruit quality. Additionally, early-stage deflowering and covering of bunches are recommended to minimize infections by T. fructigena [6][8][9]. For chemical control, metalaxyl and aluminium tris-(ethyl) phosphonate have shown efficacy in managing cigar-end rot caused by T. fructigena, while copper fungicide sprays have proven effective for disease control in cocoa.[10]
References
edit- ^ a b "Pest risk assessment made by France on Trachysphaera fructigena considered by France as harmful in French overseas departments of French Guiana, Guadeloupe, Martinique and Réunion - Scientific Opinion of the Panel on Plant Health". EFSA Journal. 6 (3). March 2008. doi:10.2903/j.efsa.2008.664. ISSN 1831-4732.
- ^ a b c TABOR, R. J.; BUNTING, R. H. (January 1923). "On a Disease of Cocoa and Coffee Fruits Caused by a Fungus Hitherto Undescribed". Annals of Botany. os-37 (1): 153–157. doi:10.1093/oxfordjournals.aob.a089833. ISSN 1095-8290.
- ^ UK, CAB International; Holliday, P. (1970-12-31). "Trachysphaera fructigena . [Descriptions of Fungi and Bacteria]". Descriptions of Fungi and Bacteria. doi:10.1079/dfb/20056400229. ISSN 2514-5592.
- ^ Wardlaw, C. W.; McGuire, Laurence P. (1931). The behaviour and diseases of the banana in storage and transport. London: H.M. Stationery Off. doi:10.5962/bhl.title.156778.
- ^ Van Der Plaats-Niterink, A. J., Samson, R. A., Stalpers, J. A., & Weijman, A. C. M (1976). "Some Oomycetes and Zygomycetes with asexual echinulate reproductive structures". Persoonia-Molecular Phylogeny and Evolution of Fungi. 9 (1): 85–93.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ a b Beugnon M, Brun J and Melin P (1970). "The control of Trachysphaera fructigena (Tabor and Bunting) a parasite of banana in Cameroun". Fruits. 25(3): 187–197.
- ^ Mouliom-Pefoura, Alassa; Sama-Lang, Patrick; Tomé, Nicolas; Tchipé, Flauribert (July 2004). "Efficacité de la ligature des inflorescences du bananier pour contrôler la maladie du bout de cigare au Cameroun". Fruits. 59 (4): 249–255. doi:10.1051/fruits:2004023. ISSN 0248-1294.
- ^ Manessy, Gabriel (1978). "Observations sur un corpus de français oral recueilli dans le Sud du Cameroun". Bulletin du Centre d'étude des plurilinguismes. 5 (1): 3–32. doi:10.3406/bcepl.1978.882. ISSN 0766-799X.
- ^ Bedimo, Joseph Mouen; Chillet, Marc; Jullien, Alexandra; Luc de Lapeyre de Bellaire (March 2003). "Le gainage précoce des régimes de bananes améliore la croissance des fruits et leur état sanitaire vis-à-vis de l'anthracnose (Colletotrichum musae)". Fruits. 58 (2): 71–81. doi:10.1051/fruits:2002037. ISSN 0248-1294.
- ^ Tezenas du Montcel H (1981). "Perspectives nouvelles dans la lutte chimique contre Trachysphaera fructigena du bananier au Cameroun". Fruit. 36(1): 3-8.
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