Browsing by Author "Pereira, A.M."
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- Effect of Bacillus subtilis on fruit yield and quality in Actinidia deliciosa orchards infected with bacterial canker in the north of PortugalPublication . Vaz, António Trindade; Moura, Luísa; Mourão, Isabel; Pereira, A.M.Bacterial canker of kiwifruit, caused by Pseudomonas syringae pv. actinidae (Psa), a disease included in the EPPO A2 List, has been registered in the north of Portugal since 2010. The relationship between the bacterium and cultural practices, namely the application of the biological control agent Bacillus subtilis in kiwifruit orchards in Portugal, is poorly understood. The most damaging phase of the disease occurs in winter and involves damage of the main vine structure and overwintering canes, and also in spring, during pollen spread, thus reducing subsequent yield and fruit quality. The main objective of this study was to evaluate the effect of B. subtilis Serenade Max® on kiwifruit yield and quality in infected orchards of different ages. Two orchards (Actinidia deliciosa ‘Hayward’) with typical symptoms of Psa were selected for yield and quality assays. Thirty plants were selected from the young orchard (6 years old) and other 30 plants were selected from the old orchard (30 years old), both located in Valença, northwest Portugal. This work showed that the use of B. subtilis as a biological control agent against Psa did not affect overall kiwifruit quality, namely the longitudinal and length diameters of fruit, the total soluble solids content, firmness, pH, titratable acidity and dry matter, but contributed significantly to increased yield in the younger orchard compared with the older orchard.
- Efficacy of Bacillus subtilis for the control of Pseudomonas syringae pv. actinidiae under field conditionsPublication . Vaz, António Trindade; Pereira, A.M.; Brito, Luís Miguel; Moura, LuísaBacterial canker of kiwifruit, caused by Pseudomonas syringae pv. actinidiae (Psa), is a disease included on the EPPO A2 List because it is currently increasing in the Mediterranean region. Climatic conditions determine the multiplication and dispersal behavior of Psa and may influence its biological control (BC). However, information regarding the influence of climatic conditions on growth of the Psa bacterium in Portugal is scarce. The aims of this study were to relate the climatic conditions with the efficacy of Bacillus subtilis Serenade Max® in controlling the disease, to determine whether disease incidence increased over the growing season, and to monitor carry-over of disease from one season to the next. Two ‘Hayward’ orchards of Actinidia deliciosa of different ages, located in Valença, in the north of Portugal, were selected for BC assay. Thirty plants were randomly selected from a young orchard (6 years old) and another 30 plants from an old one (30 years old). Psa was identified and characterized by morphological, biochemical and molecular tests. The efficacy of B. subtilis was evaluated by disease incidence, and correlated to climatic conditions. A standardized leaf infection index (0-4 scale of symptoms) was used to determine disease severity. Monitoring of Psa symptoms was performed every 30 days, from June 2016 to April 2017. The severity of the disease decreased in the summer season, characterized by unfavorable conditions for Psa such as high temperatures and scarce precipitation. B. subtilis was partially effective in controlling Psa in the 6-year-old orchard, and showed no efficacy in the protection of leaves in the 30-year-old orchard. B. subtilis applied at flowering could be considered as a suitable solution for the control of Psa biovar 3 only for the new kiwifruit orchard (6 years old).