Musa disease fact sheet on false panama disorder : symptoms, incidence, causes and recommendation

Beer, Z. de

Hernández, J.M.

International Network for the Improvement of Banana and Plantain

Sabadel, S.

CGSpace

International Network for the Improvement of Banana and Plantain, Parc Scientifique Agropolis II, 34397 Montpellier Cedex 5, FRANCETel : 33-(0)4 67 61 13 02 - Fax : 33-(0)4 67 61 03 34 - e-mail : inibap@cgiar.org - Internet : http://www.inibap.orgMusa Disease Factsheet No. 91Institute for Tropical and Subtropical Crops,Private Bag X11208, Nelspruit 1200, South Africa.2Departamento de Protección Vegetal, InstitutoCanario de Investigaciones Agrarias, Apdo. 60, La Laguna 3820, Tenerife, Spain.Figure 1.Symptoms of FalsePanama disorder. Note the yellow leaf margins andnecrotic strips,surroundedby yellowmargins.Figure 2.Skirt of deadleaves hangingdown the pseudostem ofa plant affected by FalsePanama disorder.Z. De BeerZ. De BeerThe fungus Fusarium oxysporum f.sp. cubense (Foc)causes Fusarium wilt, in the banana industry common-ly referred to as Panama disease. This disease is current-ly considered as one of the most destructive diseases incertain banana growing areas of the world. FalsePanama disorder, which can easily be confused withFusarium wilt, was first described by Deacon et al. in1985. Although the name False Panama disorder wasgiven by Deacon in 1985, a few earlier reports, possi-bly describing the same disorder, were made byPrescott, Dunlap, Permar, Barnes and Da Costa.Prescott (1917) reported the disorder as “Colorado”disease because of its presence in the Colorado districtof Honduras. Dunlap (1923) and Permar (1925) alsoreported the disorder in the Changinola area ofPanama. Barnes (1962) described similar symptoms forcultivars of the subgroup ‘Cavendish‘ in Grenada. Thename “Yellow mat” or “Mata amarilla” in Spanish wasgiven because of the pronounced yellowing of thefoliage. More recent records are those of Da Costa(1982) of Surinam. Since the late 1980’s an increasingincidence of False Panama disorder has been detectedin Tenerife, Canary Islands.External symptomsExternal symptoms of False Panama disorder can easi-ly be confused with those of Fusarium wilt. In mostcases yellowing of leaves starts with the lower or olderleaves. The margin of each leaf turns pale green to yellow, necrotic strips surrounded by a yellow marginoccur and eventually the leaf dies off (Figure 1).  Thelower leaves die completely and hang down the pseu-dostem as a skirt (Figure 2). In some instances the baseZaag de Beer1, Julio M. Hernández2 and Sonia Sabadel2(May 2001)FALSE PANAMA DISORDER ON BANANAFigure 3. Strelitzia-like growth of a banana plant affected by False Panama disorder.Figure 4. External symptoms of a Fusarium wilt infected plant. Note the uniform and pronounced yellowing of the leaf.Z. De BeerZ. De Beerof the leaf remains green and healthy, whilst the distalpart dies off. Often the upper 1-4 leaves remain greenbut are small and stunted (Figure 2).  Re-growth cantake place but bunches are found to be small withshort and thin fingers. Choked and strelitzia-like growthcharacteristics, related to stress, are often found (Figure 3).In the case of Fusarium wilt, the leaves show uniformand pronounced yellowing of the leaf margin, alongthe entire length of the leaf (Figure 4). The yellowingthen progresses inwards towards the leaf midrib andthe leaf margins turn brown and then grey. The exter-nal symptom differences between False Panama disorder and Fusarium wilt, can be clearly seen inFigures 1-4. Internal symptomsWhen a cross-section through the pseudostem of aplant showing False Panama disorder is made,approximately 50 cm above soil level, wine-red disco-lored vascular strands are often visible (Figure 5). InFusarium wilt brown to purple blotchy areas, the so-called gum pockets (Figure 6), are always present. Thepseudostem at 50-100 cm above ground level containsmany wine-red discolored vascular strands in bothFalse Panama disorder and Fusarium wilt. In Fusariumwilt the discoloration is more or less continuous andcan be traced back down the pseudostem. In the caseof False Panama disorder the discolored vascularstrands are usually discontinuous, occurring in shortregions about 10 cm long separated by wide gaps.When the rhizome is split open, False Panama disordershows brown spots and white strands, whereasFusarium-infected plants show yellow patches and yel-low strands (Figures 7 and 8).Disorder incidenceThe incidence of False Panama disorder is usually low,although as much as 60% of a plantation can be affec-ted. Since False Panama disorder can easily be confu-sed with Fusarium wilt, it is often not possible for thebanana producer to distinguish between the two. InFusarium wilt-affected areas, the occurrence of FalsePanama disorder can therefore be underestimated. False Panama disorder usually occurs in the first yearafter planting. However, in the Canary Islands and inSouth Africa it has occasionally been observed in olderplantations. These affected plants in the older planta-tions can even produce marketable fruit but can alsodie off completely. The disorder is generally observedeither in plantations planted on virgin soils or on soilswhere other crops have been previously planted, andseems not to be linked to old banana plantations.Plants affected by False Panama disorder are usuallyscattered throughout the plantation and affectedpatches including several plants, are seldom observedas is the case with Fusarium wilt. Although onlyCavendish bananas in South Africa and the CanaryIslands are affected, it seems as though most dessertbananas and plantains (AAA, AAB, ABB) includingAbaca, can be affected.Figure 5. Wine-red discolored vascular strands in a cross-sec-tion of a pseudostem affected by False Panama disorder. No gum pockets are visible.Figure 6. Brown to purple blotchy areas, the gum pockets, are always present in a cross-section through a pseudosteminfected with Fusarium wilt.Z. De BeerZ. De BeerCausesFalse Panama disorder seems not to be transmitted fromone plant to another. Up to now it has not been possibleto isolate any pathogens from affected plants despiteseveral attempts. In the Canary Islands, some Fusariumspp., including F. oxysporum, F. proliferatum, F. solaniand F. subglutinans as well as some bacteria and othercommon saprophytes were isolated. Pathogenecity testsconducted with some of the fungal isolates gave nega-tive results. Some bacterial isolates gave hypersen-sitivity reactions when tested in the Canary Islands, suggesting a potential role of these organisms in causingthe disease. Although some Fusarium spp. includingFusarium oxysporum, were isolated in South Africa, thefindings were not consistent. Success rates in isolatingorganisms from individual banana corms range fromzero to a maximum of five out of 30. Nevertheless,some bacteria and saprophytic fungi were isolated,even from deep inside the corm. In both the CanaryIslands and South Africa, it has been proven that patho-genecity tests with F. oxysporum isolated from FalsePanama disorder plants were negative. Conversely,severe Fusarium wilt symptoms occurred with F. oxysporum isolated from Fusarium wilt-infectedplants. It is therefore accepted that a fungal pathogen is not the primary cause of this disorder. Figure 7.A cross-sec-tion througha FalsePanamaaffected rhizome showingbrown spotsand whitestrands.Figure 8.Cross-sectionthrough a Fusariumwilt infectedrhizome showing yellowpatches and yellowstrands.Z. De BeerZ. De BeerFalse Panama disorder has been observed in SouthAfrica as well as in the Canary Islands to be most pro-minent in winter. However, besides low temperatures,other stress factors also occur. Some of these factorscould include nematodes, drought, nutritional imba-lances and waterlogging. A Masters degree conductedby Rabie, (1991), indicated that the root-knot nemato-de (Meloidogyne spp.) alone was not an indication ofFalse Panama disorder and suggested that additionalstress factors were involved. It is therefore suggestedthat a combination of stress factors such as drought,waterlogging, soil compaction, nutritional imbalancein combination with low temperatures, could be thecause of the disorder. However, the biotic factorsshould be further investigated.RecommendationsThe incidence of False Panama disorder can be pre-vented by reducing the incidence of stress to newlyplanted material. Nematode infestation, soil compac-tion, waterlogging, insufficient irrigation and insuffi-cient fertilizer application normally cause stress toyoung plants. Good soil preparation and soil manage-ment, to promote strong root vigor, is therefore neces-sary to prevent the occurrence of False Panama disor-der. When early symptoms of False Panama disorderare detected it is important to determine which stressfactors are involved.  If nematodes are present in thebanana roots and in the soil, appropriate treatmentshould be advised. Leaf and soil analysis can be a help-ful tool to rectify any nutrient deficiencies, while water-logged areas could be drained by digging drainagechannels. Irrigation systems, if available, should be inplace before planting and checked regularly. Soil com-paction cannot be rectified once the banana plantationhas been established and deep ripping should be carried out before planting. It is further recommendedthat banana producers have their infected plant material analyzed for Foc if they are not sure about thecause of the symptoms.ReferencesDa Costa I.C. 1982. Agricultural aspects of banana cultivationin polders in Surinam. International Symposium: Polders of theworld. Lelystad, Netherlands 2: 286-294.Barnes R.F. 1962. Grenada banana disease. Sci. Rep. Reg. Res.C., Trinidad 7.Deacon J.W., J.A. Herbert & Joasia Dames. 1985. False Panamadisorder of bananas. ITSC Information Bulletin 149: 15-18. Dunlap V.C. 1923. Weekly reports on banana investigations.United Fruit Co., Panama Div.Permar J.H. 1925. Colorado disease in the farm 8 Lacatan plan-ting. A. Rep. United Fruit Co. for period December 27, 1924 toDecember 5, 1925, Panama Div. Prescott S.C. 1917. Diseases of the banana. Bull. United FruitCo. Res. Dep. 2. Rabie E.C. 1991. Die invloed van Meloidogyne javanica en M. incognita op die voorkoms van valspanamasiekte by pie-sangs, M.Sc. thesis, PU for CHE. Potchefstroom. 106pp.

False Panama disorder on banana

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False Panama disorder on banana

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