ENFERMEDADES FÚNGICAS DE LOS CÍTRICOS EN PANAMÁ. ESTUDIO PARTICULAR DE LA MANCHA GRASIENTA CAUSADA POR Mycosphaerellaceae

[EN] Disease problems are frequently observed in citrus orchards in Panama, but in most cases their aetiology is unknown. Between 2010 and 2013 a total of 85 plots cultivated with different citrus species of citrus were surveyed in the main production areas in Panamá. Greasy spot, caused by the fungus Zasmidium citri-griseum, was identified as the most prevalent citrus disease in the country. Other fungal pathogens causing foliar and fruit diseases were also identified by the first time in Panamá: melanose caused by Diaporthe citri, postbloom fruit drop and anthracnose caused by Colletotrichum acutatum, and scab caused by Elsinoë fawcettii. A collection of 42 isolates of Mycosphaerellaceae from different citrus-growing regions in Spain, Morocco, Ghana and Panama were characterized. Strain were identified based on morphological characteristics, growth at different temperatures, ITS sequencing and pathogenicity on citrus plants. The species Amycosphaerella africana was associated with greasy spot of citrus in Spain and Morocco and Z. citri-griseum was identified as the causal agent of greasy spot in Panama, being also associated with the disease in Ghana. The study greasy spot epidemiology in Panama showed that the greatest defoliation of trees orange 'Valencia' affected by the disease occurred in the dry season between December and April. In the study of inoculum dynamics in the leaf litter, the days until complete decomposition of the leaves was related in the model with the accumulated rainfall per week (mm), days with precipitation >1 mm per week (nº) and average relative humidity per week (%). Ascospores released from the leaf litter were related with days until complete decomposition of leaves, days with precipitation >1 mm per week (nº), weekly cumulative rainfall (mm) and average temperature (ºC). Furthermore, the experiment of airborne inoculum showed that the highest levels of Z. citri-griseum inoculum were recorded during April and May, coinciding with the onset of the rainy season. Likewise, the highest values of greasy spot incidence in trap plants were recorded during the months of higher inoculum availability. Disease control experiments confirmed the efficacy of the fungicide fenbuconazole to reduce the severity of greasy spot in grapefruit and sweet orange in Panama. However, harvested yield was not significantly affected by the application of fungicide sprays.[ES] En las plantaciones de cítricos en Panamá se observan con frecuencia problemas de enfermedades, sin embargo en la mayoría de los casos se desconoce su etiología. Por tal motivo, durante los años 2010 a 2013 se prospectaron un total de 85 parcelas de diversas especies de cítricos en las principales zonas productoras del país. Se diagnosticó a la mancha grasienta, causada por Zasmidium citri-griseum, como la enfermedad más prevalente en los cítricos de Panamá. Se identificaron por primera vez en Panamá también otros patógenos fúngicos causantes de enfermedades foliares y de frutos como Diaporthe citri agente causal de la melanosis, Elsinoë fawcettii agente causal de la roña de los cítricos, Colletotrichum acutatum agente causal de la caída prematura de frutos y antracnosis. Se caracterizó una colección de 42 aislados de Mycosphaerellaceae procedentes de diferentes regiones productoras de cítricos en España, Marruecos, Ghana y Panamá. Los aislados se identificaron a nivel de especie a partir de sus características morfológicas, culturales (fisiológicas), moleculares (región ITS) y patogénicas. Se identificó la especie Amycosphaerella africana asociada a la mancha grasienta de los cítricos en España y Marruecos y Z. citri-griseum como agente causal de la mancha grasienta en Panamá, estando asociada también a la enfermedad en Ghana. En el estudio epidemiológico de la mancha grasienta en Panamá, mostró que la mayor defoliación de los árboles de naranja 'Valencia' afectados por la enfermedad ocurrió en la época seca entre los meses de diciembre a abril. En el estudio de dinámica de la producción de inóculo en la hojarasca, el modelo resultante para los días hasta la descomposición total de las hojas relaciono a las variables climáticas precipitación pluvial acumulada por semana (mm), días con precipitación pluvial >1 mm por semana (nº) y humedad relativa promedio por semana (%). En relación a las ascosporas liberadas a partir de la hojarasca el modelo resultante relaciono a las variables climáticas días hasta la descomposición total de las hojas, días con precipitación pluvial >1 mm por semana (nº), precipitación pluvial acumulada por semana (mm) y la temperatura promedio (ºC). Por otro lado, el experimento de seguimiento del inóculo en el aire, mostró que la mayor disponibilidad de inóculo de Z. citri-griseum ocurre durante los meses de abril y mayo cuando se inicia la estación de lluvias. De igual manera, la mayor incidencia de la mancha grasienta en las plantas trampa coincidió con los meses de mayor disponiblidad de inóculo. No obstante, se registraron infecciones también durante otras épocas del año. En los ensayos de control se confirmó la eficacia del fungicida fenbuconazol, que redujo significativamente la severidad de la mancha grasienta en pomelo y naranja en Panamá. Sin embargo, no se detectó un efecto significativo de los tratamientos sobre el peso de la cosecha de frutos.[CA] En les plantacions de cítrics en Panamà s'observen ben sovint problemes de malalties, no obstant això en la majoria dels casos es desconeix la seua etiologia. Per tal motiu, durant els anys 2010 al 2013 es visitaren un total de 85 parcel¿les de diverses espècies de cítrics en les principals zones productores del país. Es diagnosticà la taca greixosa, causada per Zasmidium citri-griseum, com la malaltia més àmpliament distribuïda en els cítrics de Panamà. Es van identificar per primera vegada en Panamà també altres patògens fúngics causants de malalties foliars i de fruits com Diaporthe citri agent causal de la melanosi, Elsinoë fawcettii agent causal de la ronya dels cítrics, Colletotrichum acutatum agent causal de la caiguda prematura de fruits i antracnosi. Es va caracteritzar una col¿lecció de 42 aïllats de Mycosphaerellaceae procedents de diferents regions productores de cítrics a Espanya, El Marroc, Ghana i Panamà. Els aïllats es van identificar a nivell d'espècie a partir de les seues característiques morfològiques, culturals (temperatures), moleculars (regió ITS) i patogèniques. Es va identificar l'espècie Amycosphaerella africana associada al la taca greixosa dels cítrics a Espanya i El Marroc i Z. citri-griseum com a agent causal de la taca greixosa en Panamà, estant associada també a la malaltia a Ghana. En l'estudi epidemiològic de la taca greixosa en Panamà, va mostrar que la major defoliació dels arbres de taronja 'València' afectats per la malaltia va ocórrer en l'època seca entre els mesos de desembre a abril. En el estudi de la dinàmica de la producció d'inòcul en la fullaraca, el model resultant per als dies fins a la descomposició total del les fulles es relacionà amb les variables climàtiques precipitació pluvial acumulada per setmana (mm), dies amb precipitació pluvial >1 mm per setmana (nº) i humitat relativa mitjana per setmana (%). En relació a les ascospores alliberades a partir de la fullaraca, el model resultant relacionà les variables climàtiques dies fins a la descomposició total de les fulles, dies amb precipitació pluvial >1 mm per setmana (nº), precipitació pluvial acumulada per setmana (mm) i la temperatura mitjana (ºC). D'altra banda, l'experiment de seguiment de l'inòcul en el aire, va mostrar que la major disponibilitat d'inòcul de Z. citri-griseum ocorregué durant els mesos d'abril i maig quan s'inicia l'estació de pluges. De la mateixa manera, la major incidència de la taca greixosa en les plantes trampa va coincidir amb els mesos de major disponibilitat d'inòcul. No obstant això, se van registrar infeccions també durant altres èpoques de l'any. En els assajos de control es va confirmar l'eficàcia del fungicida fenbuconazol, que va reduir significativament la severitat de la taca greixosa en pomelo i taronja en Panamà. No obstant això, no es va detectar un efecte significatiu dels tractaments sobre el pes de la collita de fruits.Aguilera Cogley, VA. (2016). ENFERMEDADES FÚNGICAS DE LOS CÍTRICOS EN PANAMÁ. ESTUDIO PARTICULAR DE LA MANCHA GRASIENTA CAUSADA POR Mycosphaerellaceae [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/61447TESI

Sensitivity of Zasmidium citri-griseum to Fenbuconazole and Control of Citrus Greasy Spot in Panama

Citrus greasy spot, caused by Zasmidium citri-griseum ( = Mycosphaerella citri) is the most prevalent fungal disease of citrus in Panama, causing premature defoliation and yield reduction. Fungicide applications are generally needed for the control of greasy spot. In this study, the sensitivity to fenbuconazole of 34 isolates of Z. citri-griseum from Panama was determined by calculating the effective concentration needed to reduce mycelial growth by 50% (EC50). Two field trials were conducted from 2011 to 2013, to evaluate the efficacy of fenbuconazole to reduce disease severity and yield loss. The EC50 values for fenbuconazole ranged from 0.09 to 7.62 μg mL−1, with a mean EC50 value of 2.66 ± 0.36 SE μg mL−1 for mycelial growth. These data can be used for monitoring sensitivity shifts in Z. citri-griseum to fenbuconazole and reduce risk of fungicide resistance in Panama. In the field trials, sprays with fenbuconazole significantly reduced (p 0.05) were detected in yield

Distribución de Diaphorina citri Kuwayama (Hemiptera: Liviidae) en zonas de producción citrícola de Panamá

Introducción. El psílido asiático (Diaphorina citri Kuwayama) es el principal vector de la bacteria Candidatus Liberibacter asiaticus que causa la enfermedad de Huanglongbing (HLB) en los cítricos en Panamá. Objetivo. Determinar la distribución geográfica y las plantas hospederas del psílido asiático dentro de las zonas citrícolas de Panamá. Materiales y métodos. El estudio se desarrolló de junio a octubre de 2021, a través de un muestreo sistemático dentro de 46 localidades asociadas a cítricos comerciales y huertos familiares en siete provincias de Panamá. En cada planta se procedió a embolsar con una bolsa plástica de cierre mágico dos brotes nuevos de ≈10 cm de largo para capturar los especímenes e introducirlos dentro de viales plásticos de 2 mm con alcohol al 95 % para su posterior identificación. La variable de estudio incluyó el conteo del número total de especímenes y los datos fueron analizados de manera porcentual. Resultados. Del total de 73 muestras colectadas, la presencia del psílido asiático se confirmó en un 21,92 % (dieciséis muestras), resultó positiva su presencia en las provincias de Chiriquí, Coclé, Herrera, Panamá y Panamá Oeste, en alturas desde los 17 hasta 1080 m s. n. m. No hubo presencia del psílido en las provincias de Los Santos y Veraguas. De las dieciséis muestras que resultaron positivas, el 50 % pertenecieron a la planta de mirto, seguida por la naranja (18,75 %) y el limón criollo (12,50 %). Conclusiones. La distribución del psílido asiático vector del HLB en parcelas de cítricos comerciales y de huertos familiares en las principales zonas citrícolas en Panamá, se presentó diferentes alturas sobre el nivel del mar, asociado a la presencia de plantas hospederas como mirto, naranja y limón criollo

Characterization of Mycosphaerellaceae species associated with citrus greasy spot in Panama and Spain

[EN] Greasy spot of citrus, caused by Zasmidium citri-griseum (= Mycosphaerella citri), is widely distributed in the Caribbean Basin, inducing leaf spots, premature defoliation, and yield loss. Greasy spot-like symptoms were frequently observed in humid citrus-growing regions in Panama as well as in semi-arid areas in Spain, but disease aetiology was unknown. Citrus-growing areas in Panama and Spain were surveyed and isolates of Mycosphaerellaceae were obtained from citrus greasy spot lesions. A selection of isolates from Panama (n = 22) and Spain (n = 16) was assembled based on their geographical origin, citrus species, and affected tissue. The isolates were characterized based on multi-locus DNA (ITS and EF-1 alpha) sequence analyses, morphology, growth at different temperatures, and independent pathogenicity tests on the citrus species most affected in each country. Reference isolates and sequences were also included in the analysis. Isolates from Panama were identified as Z. citri-griseum complex, and others from Spain attributed to Amycosphaerella africana. Isolates of the Z. citri-griseum complex had a significantly higher optimal growth temperature (26.8 degrees C) than those of A. africana (19.3 degrees C), which corresponded well with their actual biogeographical range. The isolates of the Z. citri-griseum complex from Panama induced typical greasy spot symptoms in 'Valencia' sweet orange plants and the inoculated fungi were reisolated. No symptoms were observed in plants of the 'Ortanique' tangor inoculated with A. africana. These results demonstrate the presence of citrus greasy spot, caused by Z. citri-griseum complex, in Panama whereas A. africana was associated with greasy spot-like symptoms in Spain.Research was partially funded by 'Programa de Formacion de los INIA Iberoamerica' and INIA RTA2010-00105-00-00-FEDER to Vidal Aguilera Cogley.. We thank J. Martinez-Minaya (UV) for assistance with INLAAguilera-Cogley, VA.; Berbegal Martinez, M.; Català, S.; Collison Brentu, F.; Armengol Fortí, J.; Vicent Civera, A. (2017). Characterization of Mycosphaerellaceae species associated with citrus greasy spot in Panama and Spain. PLoS ONE. 12(12):1-19. https://doi.org/10.1371/journal.pone.0189585S1191212Crous, P. W., Summerell, B. A., Carnegie, A. J., Wingfield, M. J., Hunter, G. C., Burgess, T. I., … Groenewald, J. Z. (2009). Unravelling Mycosphaerella: do you believe in genera? Persoonia - Molecular Phylogeny and Evolution of Fungi, 23(1), 99-118. doi:10.3767/003158509x479487Mondal, S. N., & Timmer, L. W. (2006). Greasy Spot, a Serious Endemic Problem for Citrus Production in the Caribbean Basin. Plant Disease, 90(5), 532-538. doi:10.1094/pd-90-0532Whiteside, J. O. (1970). Etiology and Epidemiology of Citrus Greasy Spot. Phytopathology, 60(10), 1409. doi:10.1094/phyto-60-1409Huang, F., Groenewald, J. Z., Zhu, L., Crous, P. W., & Li, H. (2015). Cercosporoid diseases of Citrus. Mycologia, 107(6), 1151-1171. doi:10.3852/15-059Wellings, C. R. (1981). Pathogenicity of fungi associated with citrus greasy spot in New South Wales. Transactions of the British Mycological Society, 76(3), 495-499. doi:10.1016/s0007-1536(81)80080-0Marco, G. M. (1986). A Disease Similar to Greasy Spot but of Unknown Etiology on Citrus Leaves in Argentina. Plant Disease, 70(11), 1074a. doi:10.1094/pd-70-1074aVidal Aguilera-Cogley, & Antonio Vicent. (2015). FUNGAL DISEASES OF CITRUS IN PANAMA. Acta Horticulturae, (1065), 947-952. doi:10.17660/actahortic.2015.1065.118Honger J. Aetiology and importance of foliage diseases affecting citrus in the nursery at the Agricultural Research Station (ARS). PhD Thesis. Accra: University of Ghana; 2004.Vicent A, Álvarez A, León M, García-Jiménez J. Mycosphaerella sp. asociada a manchas foliares de cítricos en España. In: Proceedings of the 13th Congress of the Spanish Phytopathological Society. 2006; Murcia; Spain.Abdelfattah, A., Cacciola, S. O., Mosca, S., Zappia, R., & Schena, L. (2016). Analysis of the Fungal Diversity in Citrus Leaves with Greasy Spot Disease Symptoms. Microbial Ecology, 73(3), 739-749. doi:10.1007/s00248-016-0874-xQuaedvlieg, W., Binder, M., Groenewald, J. Z., Summerell, B. A., Carnegie, A. J., Burgess, T. I., & Crous, P. W. (2014). Introducing the Consolidated Species Concept to resolve species in the Teratosphaeriaceae. Persoonia - Molecular Phylogeny and Evolution of Fungi, 33(1), 1-40. doi:10.3767/003158514x681981Edgar, R. C. (2004). MUSCLE: multiple sequence alignment with high accuracy and high throughput. Nucleic Acids Research, 32(5), 1792-1797. doi:10.1093/nar/gkh340Darriba, D., Taboada, G. L., Doallo, R., & Posada, D. (2012). jModelTest 2: more models, new heuristics and parallel computing. Nature Methods, 9(8), 772-772. doi:10.1038/nmeth.2109Ronquist, F., Teslenko, M., van der Mark, P., Ayres, D. L., Darling, A., Höhna, S., … Huelsenbeck, J. P. (2012). MrBayes 3.2: Efficient Bayesian Phylogenetic Inference and Model Choice Across a Large Model Space. Systematic Biology, 61(3), 539-542. doi:10.1093/sysbio/sys029Rambaut A. FigTree v1. 4.0, a graphical viewer of phylogenetic trees. Edinburgh, Scotland: University of Edinburgh; 2016.Spiegelhalter, D. J., Best, N. G., Carlin, B. P., & van der Linde, A. (2002). Bayesian measures of model complexity and fit. Journal of the Royal Statistical Society: Series B (Statistical Methodology), 64(4), 583-639. doi:10.1111/1467-9868.00353Rue, H., Martino, S., & Chopin, N. (2009). Approximate Bayesian inference for latent Gaussian models by using integrated nested Laplace approximations. Journal of the Royal Statistical Society: Series B (Statistical Methodology), 71(2), 319-392. doi:10.1111/j.1467-9868.2008.00700.xChristensen RH. Ordinal—regression models for ordinal data. R package version 2015.1–21. 2015. http://www.cran.r-project.org/package=ordinal/ Accessed 8 May 2017.Hunter, G. C., Wingfield, B. D., Crous, P. W., & Wingfield, M. J. (2006). A multi-gene phylogeny for species of Mycosphaerella occurring on Eucalyptus leaves. Studies in Mycology, 55, 147-161. doi:10.3114/sim.55.1.147Braun, U., & Urtiaga, R. (2013). New species and new records of cercosporoid hyphomycetes from Cuba and Venezuela (Part 2). Mycosphere, 4(2), 172-214. doi:10.5943/mycosphere/4/2/3Braun, U., Crous, P. W., & Nakashima, C. (2014). Cercosporoid fungi (Mycosphaerellaceae) 2. Species on monocots (Acoraceae to Xyridaceae, excluding Poaceae). IMA Fungus, 5(2), 203-390. doi:10.5598/imafungus.2014.05.02.04Aptroot A. Mycosphaerella and its anamorphs: conspectus of Mycosphaerella CBS Biodiversity Series 5. Utrecht: CBS-KNAW Fungal Biodiversity Centre; 2006.Crous, P. W., & Wingfield, M. J. (1996). Species of Mycosphaerella and Their Anamorphs Associated with Leaf Blotch Disease of Eucalyptus in South Africa. Mycologia, 88(3), 441. doi:10.2307/3760885Aguín, O., Sainz, M. J., Ares, A., Otero, L., & Pedro Mansilla, J. (2013). Incidence, severity and causal fungal species of Mycosphaerella and Teratosphaeria diseases in Eucalyptus stands in Galicia (NW Spain). Forest Ecology and Management, 302, 379-389. doi:10.1016/j.foreco.2013.03.021Maxwell, A., Dell, B., Neumeister-Kemp, H. G., & Hardy, G. E. S. J. (2003). Mycosphaerella species associated with Eucalyptus in south-western Australia: new species, new records and a key. Mycological Research, 107(3), 351-359. doi:10.1017/s0953756203007354Otero L, Aguín O, Mansilla J, Hunter G, Wingfield M. Identificación de especies de Mycosphaerella en Eucalyptus globulus y E. nitens en Galicia. In: Proceedings of the 13th Congress of the Spanish Phytopathological Society; 2006; Murcia, Spain.ZHAN, J., & McDONALD, B. A. (2011). 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Occurrence and distribution of Bemisia tabaci and Trialeurodes vaporariorum (Hemiptera: Aleyrodidae) on tomato crops in Panama

The main open-field and greenhouse producer regions of tomato in Panama (Los Santos, Herrera, Veraguas and Chiriquí provinces) were surveyed to determine the occurrence and distribution of Bemisia tabaci and Trialeurodes vaporariorum during the growing seasons of 2017 and 2018. Twenty-two plots were surveyed, and DNA extracts of 112 adult whiteflies were analyzed by multiplex PCR, using a set of specific primers of B. tabaci MEAM1, B. tabaci NW, and T. vaporariorum. DNA extracts corresponding to 57 individual whiteflies (50.9 %) rendered PCR products of expected size with B. tabaci-specific primers (37 belonged to B. tabaci MEAM1 and 20 to B. tabaci NW), whereas the remaining DNA extracts corresponding to 55 individual whiteflies (49.1 %) rendered the product of the expected size with T. vaporariorumspecific primers. The sequencing of those PCR products and BLAST analysis allowed for the identification of B. tabaci MEAM1, B. tabaci NW, and T. vaporariorum. Bemisia tabaci NW was detected in all four provinces, while B. tabaci MEAM1 was detected in the provinces of Los Santos, Herrera and Chiriquí, and T. vaporariorum was detected only in the province of Chiriquí. Bemisia tabaci MEAM1, B. tabaci NW and T. vaporariorum were detected in both production systems (open fields and greenhouse). Bemisia tabaci MEAM1 and B. tabaci NW were detected in the tropical rainforest (Af) and tropical savanna (Aw) climates, at an altitudinal range of 19–1543 meters above sea level (MASL), while Trialeurodes vaporariorum was found only in the Af climate, at an altitudinal range of 818–1661 MASL. To our knowledge, this is not only the first report of B. tabaci MEAM1 and B. tabaci NW at an altitude above 1000 MASL in Panama, but it is also the first report of T. vaporariorum at an altitude under 1000 MASL in this country. Information about the identification and geographic distribution of whiteflies in Panama will help to design effective strategies for pest management

Aprovechamiento del calor residual en la central termoeléctrica de Miraflores – Canal de Panamá

Treball Final de Master Universitari en Eficiència Energètica i Sostenibilitat (Pla de 2013) Codi: SIV034. Curs acadèmic: 2014-201

Acta Horticulturae

The citrus-growing area in Panama has increased considerably in recent years. Disease problems are frequently observed in orchards, but in most cases their etiology is unknown, complicating the design of effective control strategies. A survey was initiated in 2010, visiting 50 orchards in different regions of the country. In each orchard, symptoms were characterized and samples were collected from the affected organs. Isolations from symptomatic tissues were made on general and selective media and then the fungal isolates were transferred to PDA and V8-juice agar for morphological identification. Molecular identification was carried out on representative isolates by amplifying and sequencing the internal transcribed spacer (ITS) region. Mycosphaerella citri, the causal agent of citrus greasy spot, was isolated from necrotic pustules on the leaves of trees showing chlorosis, and premature defoliation, which were observed in 75% of the surveyed orchards. This disease was found to be the prevalent fungal disease of citrus in Panama. Colletotrichum acutatum was consistently isolated from petals and from fruits that dropped prematurely from lime and sweet orange orchards and pathogenicity tests identified the isolates as the causal agent of Key lime anthracnose disease. Furthermore, melanose on sweet orange leaves and fruits was associated with Phomopsis sp

Inoculum and disease dynamics of citrus greasy spot caused by Zasmidium citri-griseum in sweet orange in Panama

Citrus greasy spot, caused by Zasmidium citri-griseum, is a disease characterized by inducing premature defoliation and a reduction in yield in different citrus species. Greasy spot is the most prevalent fungal disease in sweet orange in Panama. Nevertheless, no epidemiological information is available. In this study, the dynamics of the defoliation, inoculum production, airborne inoculum and infection periods of Z. citri-griseum and their associations with environmental conditions were determined in Panama. The period from December to April was characterized by greater defoliation of trees, with the greatest amount of leaf litter being produced in January and February. The number of days until total leaf decomposition (DLD) was related to the number of rainy days >1 mm (NRD), accumulated rainfall (AR) and average relative humidity (ARH). The number of ascospores released from leaf litter (ASCL) was related to DLD, NRD, AR and average temperature (AT). The greatest amounts of airborne ascospores (AASC) of Z. citri-griseum occurred during April and May, when the rainy season begins in Panama. Similarly, the highest incidence (INC) of greasy spot in the trap plants coincided with the months of the greatest availability of airborne ascospores. However, infections were also recorded during other times of the year. The AASC or INC data were fitted to Bayesian models including meteorological variables and an autoregressive temporal component, the latter being the most influential. The results obtained in this study will allow the development of more efficient and sustainable fungicide programmes for greasy spot control in Panama

El virus del mosaico amarillo de la papa de Panamá (PYMPV): un patógeno emergente que infecta tomate industrial en la provincia de Los Santos, Panamá

ABSTRACT Begomoviruses (genus Begomovirus, family Geminiviridae) constitute the main phytosanitary problem of tomato crop in tropical and subtropical regions of the world. These viruses are transmitted by the whitefly Bemisia tabaci, which in recent years has had a significant increase in its populations, and has been associated with the appearance of viral symptoms in tomato crops in Panama. A survey was carried out on industrial tomato crops from Los Santos province in the period 2016-2017, with the objective of determine the incidence of begomovirus in this region. Seventy leaf samples from tomato plants showing symptoms associated to viral infections were collected in nine plots located in seven distinct locations, which constitute the main tomato producing zones in this province. DNA extraction was performed from each sample and the extracts were analyzed by the polymerase chain reaction (PCR) technique, using two pairs of degenerate primers to detect the genus Begomovirus. Samples that showed a positive reaction were analyzed with specific primers to identify the three begomovirus species that infect tomato in Panama, being these, Potato yellow mosaic Panama virus (PYMPV), Tomato yellow mottle virus (TYMoV) and Tomato leaf curl Sinaloa virus (ToLCSiV). Fifty-eight (58) tomato samples (82.9% of the total samples collected) were begomovirus positive. One hundred percent (100%) of these samples was infected with PYMPV. The presence of TYMoV and ToLCSiV was not determined in the analyzed samples. These results were confirmed by DNA sequencing and sequences analysis. The association of PYMPV with the serious damage recently suffered by the tomato industry with the decrease of its production is discussed in this study.RESUMEN Los begomovirus (género Begomovirus, familia Geminiviridae) constituyen el principal problema fitosanitario del cultivo de tomate en las regiones tropicales y subtropicales del mundo. Estos virus se transmiten por la mosca blanca Bemisia tabaci, la que en los últimos años ha tenido un incremento significativo en sus poblaciones, y se ha asociado con la aparición de síntomas virales en cultivos de tomate en Panamá. Se realizó una prospección en cultivos de tomate industrial en la provincia de Los Santos en el período 2016-2017, con el objetivo de determinar la incidencia de begomovirus en esta región. Se recolectaron 70 muestras de hojas de plantas de tomate mostrando síntomas asociados a infecciones virales, en nueve parcelas ubicadas en siete localidades distintas, quienes constituyen las principales zonas productoras de tomate en esta provincia. Se realizó la extracción de ADN de cada muestra y los extractos se analizaron mediante la técnica de reacción en cadena de la polimerasa (PCR), utilizando dos parejas de iniciadores degenerados para detectar begomovirus. Las muestras que mostraron una reacción positiva se analizaron con iniciadores específicos para identificar las tres especies de begomovirus que infectan tomate en Panamá, siendo estas, el virus del mosaico amarillo de la papa de Panamá (PYMPV), virus del moteado amarillo del tomate (TYMoV) y el virus del enrollamiento de la hoja de tomate de Sinaloa (ToLCSiV). Cincuenta y ocho (58) muestras de tomate (82,9% del total de muestras recolectadas) resultaron positivas a begomovirus. El 100% de estas muestras resultó infectado con PYMPV. No se determinó la presencia de TYMoV y ToLCSiV en las muestras analizadas. Estos resultados se confirmaron mediante secuenciación de ADN y análisis de secuencias. Se discute en este estudio la asociación de PYMPV con los graves daños que ha sufrido recientemente el sector tomatero con la baja de su producción