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Candidatus Liberibacter solanacearum (Lso) es una bacteria gram-negativa, vascular, limitada
al floema de la planta, ampliamente distribuida en diferentes cultivos de las familias Apiaceae
spp. y Solanaceae spp, transmitida por psílidos (Hemiptera: Triozidae) y de la que se han
descrito hasta 10 haplotipos. En patata es responsable de la enfermedad conocida como Zebra
Chip (ZC), problema de gran importancia en este cultivo en aquellas zonas donde el psílido
Bactericera cockerelli (Sulc) está ampliamente distribuido. En el año 2013 se detectó la
presencia de Lso en tubérculos de patata en Castilla y León, sin embargo, aún no se ha
detectado la enfermedad en condiciones de cultivo, desconociéndose distintos aspectos de la
etiología y epidemiología.
Con el objetivo principal de conocer qué importancia tiene ZC en el cultivo de patata de
Castilla y León, a través de la identificación de los psílidos vectores, estudiando su
abundancia, momentos de aparición en el cultivo y su riesgo de transmisión; la detección del
patógeno e identificación de sus síntomas en planta y en tubérculo; el estudio etiológico con
la búsqueda de la bacteria en posibles plantas huéspedes y el potencial de transmisión de
tubérculo a planta, se realizaron muestreos ocasionales y periódicos en las zonas productoras
de patata de siembra y de consumo de Castilla y León y se estableció un ensayo en la localidad
de Zamadueñas (Valladolid) durante los años 2016, 2017 y 2018.
La especie de psílido mayormente encontrada tanto en los muestreos periódicos como
ocasionales con todos los métodos de monitoreo realizados fue Bactericera nigricornis
Förster, con unos niveles de capturas bajos, que se produjeron principalmente entre los meses
de junio y agosto. El porcentaje de B. nigricornis portadores de Lso encontrado fue del 3,01
% en los muestreos periódicos y del 2% en los muestreos ocasionales. El pico poblacional
máximo fue de 0,73 insectos/mangueo en 2018 en Zamadueñas, donde se pudo constatar que
B. nigricornis era capaz de completar ciclo en este cultivo.
En los muestreos ocasionales realizados en parcelas convencionales de patata y distribuidos
en parcelas de patata de la región, solo se detectó Lso en siete plantas, seis de ellas con
síntomas de tubérculos aéreos y una planta sin síntomas y en nueve plantas con síntomas muy
inespecíficos en las plantas monitoreadas del ensayo realizado en la localidad de Zamadueñas.
En los tubérculos, el porcentaje de Lso nunca fue superior al 2%, no encontrando diferencias
significativas entre las variedades estudiadas.
Con el nivel de plantas e insectos portadores de la bacteria encontrado, no parece que ZC sea
un problema grave en Castilla y León, sin embargo, es suficiente para encontrar la bacteria en los tubérculos, pero no es fácil detectar la bacteria en las plantas. A pesar de eso, los
porcentajes de tubérculos afectados no suponen una pérdida importante de la cosecha.
No se encontró la bacteria en el análisis de las plantas silvestres próximas al cultivo de la
patata en la zona de siembra, lo que parece indicar que la transmisión proviene de zonas donde
la zanahoria comparte espacio con la patata y donde B. nigricornis podría adquirir la bacteria,
teniendo en cuenta el riesgo limitado de transmisión en patata de Bactericera trigonica. El
riesgo de transmisión de planta a tubérculo no parece ser importante, ya que más de la mitad
de los tubérculos de plantas positivas eran no viables.
Candidatus Liberibacter solanacearum (Lso) is Gram-negative and vascular bacteria that live as phloem-limited obligate parasites in plants, widely distributed in Apiaceae and Solanaceae spp., transmitted by psyllids (Hemiptera: Triozidae) and with 10 haplotypes described. Lso is responsible for the transmission of Zebra Chip (ZC) disease, considered a problem in potato culture areas where Bactericera cockerelli (Sulc) is widely distributed. Lso were detected in potato tubers in Castilla y León in 2013, although, symptoms of the disease have not been detected yet in potato plants, and aspects about its etiology and epidemiology remains unknown. With the main objective to know what is the importance of ZC in potato culture of Castilla y León, by the identification of vectors psyllids, studying their abundance and appearance relative to the emergence of the crop and risk of transmission; pathogen detection and symptoms identification in plants and tubers; the etiology study with bacteria detection in host plants and the potential for transmission of plant to tuber, occasional and regular surveys were carried in cultivated area of seed and consumption potatoes of Castilla y León and a trial field was conducted in the locality of Zamadueñas (Valladolid) during 2016, 2017 and 2018. The psyllid species found more frequently but very scarce in occasional and regular surveys monitored of all sampling methods was B. nigricornis, appearing more frequently during the months of June to August. The percentage of B. nigricornis positive to Lso was 3.01 % in regular surveys and 2% in occassional surveys. The maximum peak was 0.73 insects by sweep in 2018 in Zamadueñas, where B. nigricornis was able to complete the hole life cycle on potato. Only seven positive plants were detected in occasional surveys conducted in the cultivated areas of potato of the region, six of them with aerial tubers and another one without symptoms. Nine plants with unspecific symptoms was positive to Lso in the field trial located in Zamadueñas. The percentage of Lso in tubers was lower than 2 %, with no significative differences between the cultivars of potato studied. Considering the level of positive plants and psyllids founded, ZC does not seem to be a serious problem in Castilla y León, however, this level is enough to detect the bacteria in tubers, but it is not easy to detect Lso in plants. Despite this, the percentage of affected tubers does not cause losses at harvest. The bacteria were not detected in the analysis in wild plants close to seed potato fields, indicating that the risk of transmission of Lso originates from carrot fields close to potato where B. nigricornis was able to acquire the bacteria, considering that the transmission from carrot to potato by Bactericera trigonica seems to be very limited. The potential of transmission to plant to tuber was low, more than half tubers from positive plants were not viable.
Candidatus Liberibacter solanacearum (Lso) is Gram-negative and vascular bacteria that live as phloem-limited obligate parasites in plants, widely distributed in Apiaceae and Solanaceae spp., transmitted by psyllids (Hemiptera: Triozidae) and with 10 haplotypes described. Lso is responsible for the transmission of Zebra Chip (ZC) disease, considered a problem in potato culture areas where Bactericera cockerelli (Sulc) is widely distributed. Lso were detected in potato tubers in Castilla y León in 2013, although, symptoms of the disease have not been detected yet in potato plants, and aspects about its etiology and epidemiology remains unknown. With the main objective to know what is the importance of ZC in potato culture of Castilla y León, by the identification of vectors psyllids, studying their abundance and appearance relative to the emergence of the crop and risk of transmission; pathogen detection and symptoms identification in plants and tubers; the etiology study with bacteria detection in host plants and the potential for transmission of plant to tuber, occasional and regular surveys were carried in cultivated area of seed and consumption potatoes of Castilla y León and a trial field was conducted in the locality of Zamadueñas (Valladolid) during 2016, 2017 and 2018. The psyllid species found more frequently but very scarce in occasional and regular surveys monitored of all sampling methods was B. nigricornis, appearing more frequently during the months of June to August. The percentage of B. nigricornis positive to Lso was 3.01 % in regular surveys and 2% in occassional surveys. The maximum peak was 0.73 insects by sweep in 2018 in Zamadueñas, where B. nigricornis was able to complete the hole life cycle on potato. Only seven positive plants were detected in occasional surveys conducted in the cultivated areas of potato of the region, six of them with aerial tubers and another one without symptoms. Nine plants with unspecific symptoms was positive to Lso in the field trial located in Zamadueñas. The percentage of Lso in tubers was lower than 2 %, with no significative differences between the cultivars of potato studied. Considering the level of positive plants and psyllids founded, ZC does not seem to be a serious problem in Castilla y León, however, this level is enough to detect the bacteria in tubers, but it is not easy to detect Lso in plants. Despite this, the percentage of affected tubers does not cause losses at harvest. The bacteria were not detected in the analysis in wild plants close to seed potato fields, indicating that the risk of transmission of Lso originates from carrot fields close to potato where B. nigricornis was able to acquire the bacteria, considering that the transmission from carrot to potato by Bactericera trigonica seems to be very limited. The potential of transmission to plant to tuber was low, more than half tubers from positive plants were not viable.
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Palavras-chave
Candidatus Liberibacter solanacearum (Lso) Bactericera spp. Vector Tubérculo Siembra Consumo Monitoreo Síntomas Transmisión Planta