The management of bacterial plant diseases is nowadays limited to copper compounds, regulated by European Union since 2020, to reduce dependence on chemicals until reaching Zero-tolerance within 2030, or to few biological control agents (BCAs). In this study, the efficacy of the foliar fertilizer Probaction® (0.3% and 0.4%) was tested in vitro against strains of Xanthomonas vesicatoria (Xv), X. fragariae (Xf), Pseudomonas savastanoi subsp. savastanoi (Pss) and Erwinia amylovora (Ea). Probaction® was also tested in planta under controlled conditions against bacterial leaf spot of tomato (BLST) and towards strawberry angular leafspot (ALS) caused by Xv and Xf, respectively. On tomato plants cv. VF10, Probaction® (0.3%) was applied at the leaves or at the root apparatus, while on strawberry plants cv. Tea, Probaction® (0.4%) was treated at the leaves. After 24 h, the treated tomato or strawberry plants were inoculated by spraying the Xv or Xf suspension at the leaves; streptomycin sulphate (100 ppm) and sterile distilled water (SDW) were used as positive and negative controls, respectively. In vitro, Probaction® inhibited the growth of Xf, but it was not effective against Xv, Pss and Ea. In planta, the tomato plants treated at leaves or at roots showed a lower BLST severity (ca. 18 and 14 spots/leaf, respectively), compared to that on negative control plants (SDW, ca. 27 spots/leaf). On strawberry plants, Probaction® gave a relative protection (RP), related to SDW treated plants, of about 67%; while streptomycin sulphate, used as positive control, gave about 44%RP. In conclusion, the efficacy of Probaction® in reducing BLST severity, associated to its inability in inhibiting Xv growth in vitro, may suggest its role in triggering the plant immune response; while its direct efficacy in reducing ALS severity offers a valid alternative to chemicals in the disease management to reduce the Xf inoculum sources.
E. Biondi, N.B. (2023). A novel biological tool for the control of plant diseases caused by the bacterial pathogens Xanthomonas vesicatoria and X . fragariae.
A novel biological tool for the control of plant diseases caused by the bacterial pathogens Xanthomonas vesicatoria and X . fragariae
E. Biondi;N. Biondo;P. Minardi
2023
Abstract
The management of bacterial plant diseases is nowadays limited to copper compounds, regulated by European Union since 2020, to reduce dependence on chemicals until reaching Zero-tolerance within 2030, or to few biological control agents (BCAs). In this study, the efficacy of the foliar fertilizer Probaction® (0.3% and 0.4%) was tested in vitro against strains of Xanthomonas vesicatoria (Xv), X. fragariae (Xf), Pseudomonas savastanoi subsp. savastanoi (Pss) and Erwinia amylovora (Ea). Probaction® was also tested in planta under controlled conditions against bacterial leaf spot of tomato (BLST) and towards strawberry angular leafspot (ALS) caused by Xv and Xf, respectively. On tomato plants cv. VF10, Probaction® (0.3%) was applied at the leaves or at the root apparatus, while on strawberry plants cv. Tea, Probaction® (0.4%) was treated at the leaves. After 24 h, the treated tomato or strawberry plants were inoculated by spraying the Xv or Xf suspension at the leaves; streptomycin sulphate (100 ppm) and sterile distilled water (SDW) were used as positive and negative controls, respectively. In vitro, Probaction® inhibited the growth of Xf, but it was not effective against Xv, Pss and Ea. In planta, the tomato plants treated at leaves or at roots showed a lower BLST severity (ca. 18 and 14 spots/leaf, respectively), compared to that on negative control plants (SDW, ca. 27 spots/leaf). On strawberry plants, Probaction® gave a relative protection (RP), related to SDW treated plants, of about 67%; while streptomycin sulphate, used as positive control, gave about 44%RP. In conclusion, the efficacy of Probaction® in reducing BLST severity, associated to its inability in inhibiting Xv growth in vitro, may suggest its role in triggering the plant immune response; while its direct efficacy in reducing ALS severity offers a valid alternative to chemicals in the disease management to reduce the Xf inoculum sources.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
