Epidemiología y daños causados por un nuevo complejo viral de batata en la Pcia. de Córdoba

Abstract

Se iniciaron estudios de prospección, epidemiología y daños en lotes de batata de Colonia Caroya con síntomas de un complejo viral, durante tres campañas sucesivas. Fueron detectados sweet potato feathery mottle virus (SPFMV), sweet potato virus G (SPVG), sweet potato chlorotic stunt virus (SPCSV) y sweet potato leaf curl virus (SPLCV). Al comparar plantas con síntomas severos vs. plantas con síntomas suaves, los daños en componentes de rendimiento fueron menores que en plantas con síntomas severos vs. asintomáticas (mermas en peso fresco y número de raíces comerciales de 44 y 45% y 94 y 86%, respectivamente). Incidencia y prevalencia de los diferentes virus se incrementaron en campañas sucesivas. La mayor severidad de síntomas sucedió en infecciones dobles, triples y cuádruples en las que participaron SPCSV y SPFMV. Los daños provocados por el complejo viral fueron corroborados en sendos ensayos comparativos de rendimiento; el primero incluía plantas infectadas con complejo viral vs. plantas con sanidad controlada y el segundo, plantas con complejo viral vs. plantas asintomáticas procedentes del primer ensayo. Los mismos fueron significativos en lotes comerciales y en ensayos experimentales, por lo que la única forma de control eficiente es el uso de propágulos con sanidad controlada. La presencia de los virus responsables del complejo en plantines de diversa procedencia indica que el empleo de semilla foránea conlleva su dispersión.

During three successive agricultural seasons, survey, epidemiology, and damage studies were carried out in sweet potato fields, showing symptoms of a viral complex in Colonia Caroya. The following viruses were present in all the evaluated fields: sweet potato feathery mottle virus (SPFMV), sweet potato virus G (SPVG), sweet potato chlorotic stunt virus (SPCSV), and sweet potato leaf curl virus (SPLCV). When comparing yield reduction between severely and mildly symptomatic plants, losses of 44 and 45% were recorded for fresh weight and number of commercial roots, respectively. These losses were 94 and 86%, respectively, in the second agricultural season (comparing severely affected and asymptomatic plants). Additionally, the incidence and prevalence of the different viruses increased in successive seasons, and the highest symptom severity was observed in double, triple, and quadruple infections involving SPCSV and SPFMV. The damage caused by the viral complex was confirmed in two comparative yield trials. In the first trial, plants affected by the viral complex were compared to healthy plants obtained by tissue culture, while in the second trial, the comparison was made between plants with the viral complex and asymptomatic plants harvested from the first trial. The damage caused by the viral complex was significant both, in commercial plots and experimental trials, indicating that the only efficient control method is using healthy explants obtained through micropropagation. The presence of the viruses responsible for this complex in seedlings of various origins indicates that the use of foreign seedlings leads to their dispersion.