Betina Pereira de Bem

Effect of four training systems on the temporal dynamics of downy mildew in two grapevine cultivars in southern Brazil

The aim of this study was to evaluate the temporal dynamics of downy mildew epidemics under four training systems: vertical shoot positioning (VSP), Geneva Double Curtain (GDC), Simple Curtain (SC) and Tendone in two cultivars (‘Cabernet Sauvignon’ and ‘Merlot’). Experiments were conducted at commercial vineyards in southern Brazil, during the 2012–2013 and 2013–2014 growing seasons. Downy mildew incidence and severity were quantified on a weekly basis from the first symptoms appearance until harvest. Training systems and cultivars were compared based on the following variables of downy mildew progress curves: a) beginning of symptoms appearance (BSA); b) maximum disease incidence and severity (Imax, Smax); c) time to reach maximum disease incidence/severity (TRMDI and TRMDS); and d) area under incidence and severity disease progress curve (AUIDPC and AUSDPC). The training systems significantly affected AUSDPC and Smax. AUSDPC was lowest in the VSP system in all cultivars and growing seasons. In addition, ‘Merlot’ showed significantly lower AUIDPC and AUSDPC than ‘Cabernet Sauvignon’ in both growing seasons. The Tendone and GDC systems showed significantly higher AUSDPC in all cultivars and growing seasons. Our results suggested that the use of the VSP system contributes to reduce downy mildew severity on ‘Merlot’ and ‘Cabernet Sauvignon’ in southern Brazil.

Época de desfolha e sua influência no desempenho vitícola da uva ‘Sauvignon Blanc’ em região de elevada altitude

The winegrape is characterized as a demanding species in cultural dealings and in order to reach optimal conditions at the time of harvest it is fundamental that the management techniques are adequate the characteristics of each region, being the leaf removal has been an important management of the vegetative canopy, which can improve the chemical composition of the bunches and increase the productive efficiency of the vine. The objective of this study was to evaluate the leaf removal effect on the agronomic performance and maturation ad the productive efficiency of the Sauvignon Blanc grape in high altitude regions of Santa Catarina. The experiment was conducted in 2015 and 2016 vintages, in a commercial vineyard, located in Sao Joaquim, Santa Catarina State (28°17’39”S; 49°55’56”W, altitude 1,230m a.s.l.). The leaf removal was carried out in cluster zone in the following phenological stages: full bloom, buckshot berries, pea-sized berries, veraison, 15 days after veraison and control without leaf removal. The results were submitted to analysis of variance and Scott-Knott test (5% probability). It was observed that the leaf removal carried before veraison increase the fertility index. The leaf removal carried out in the phenological pea-sized berries and veraison presented the highest yields in relation to the other phenological stages and plants not submitted to the management of leaf removal. In addition, the leaf removal improved the technological and phenolic maturation of the Sauvignon Blanc grape when it was carried out in the phenological stages buckshot berries and pea-sized berries in the two harvests evaluated. The results of this study evidenced the importance the leaf removal to obtain a must with potential for the elaboration of quality fine wines, especially when carried out between the phenological stages of buckshot berries and pea-sized berries. Therefore, the leaf removal of the Sauvignon Blanc grapevine in high altitude regions should be considered an indispensable management practice for the vitivinicultor.

Efeitos do manejo da cobertura do solo na maturação da videira Merlot cultivada em região de elevada altitude

Tem-se como objetivo deste trabalho comparar a maturacao tecnologica e fenolica da videira Merlot em regiao de elevada altitude de Santa Catarina cultivada em com solo coberto por vegetacao e solo sem cobertura vegeta. O presente trabalho foi realizado na safra 2014/2015 em um vinhedo comercial situado no municipio de Sao Joaquim – Santa Catarina. O delineamento experimental utilizado foi o de blocos ao acaso, com quatro blocos e dez plantas por bloco. Foi utilizado um vinhedo da variedade Merlot, enxertada sobre ‘Paulsen 1103’. Os tratamentos consistiram em manter a linha de cultivo com cobertura vegetal natural e manter a linha de cultivo sem cobertura vegetal. Para manter a linha de cultivo sem cobertura vegetal foi realizado capina manual a partir do estagio fenologico virada de cor, sendo esta operacao repetida a cada 15 dias ate o momento da colheita. Avaliou-se a maturacao tecnologica e fenolica das bagas, alem da massa de baga e relacao casca/baga. Observou-se efeito da cobertura do solo na maturacao da videira Merlot, em solo sem cobertura vegetal na linha de cultivo, houve incremento da relacao casca/baga, pH e antocianinas. Portanto o solo sem cobertura vegetal resultou em uma melhor maturacao da videira Merlot cultivada em regiao de elevada altitude.

Relationship among Entomosporium severity, defoliation, and vegetative-reproductive variables in pear in Brazil

The objective of this work was to evaluate the relationship among Entomosporium severity, defoliation, and vegetative-reproductive variables of three European pear cultivars in Southern Brazil. The Packham’s Triumph, Abate Fetel, and Williams pear cultivars were assessed regarding Entomosporium severity, defoliation, and natural leaf fall every two weeks, from the appearance of the first symptoms at the beginning of January until the end of April, during the 2012/2013 and 2013/2014 crop seasons. The vegetative and reproductive variables were evaluated in July, during the dormant period. Data on Entomosporium severity were integrated over time and converted into the area under the disease progress curve (AUDPC). The coefficient of determination (R2) of the linear regression of Entomosporium severity versus defoliation was significant for all studied cultivars and crop seasons. Defoliation in trees affected by Entomosporium was significantly higher than natural leaf fall in the control trees protected by fungicides. A negative correlation was observed among defoliation, branch fertility index, and plant height, indicating that the higher the defoliation, the lower the development of the vegetative and reproductive variables plant height and vigor. Entomosporium severity differed significantly among cultivars when the AUDPC was considered the differentiating epidemiological variable. The Abate Fetel and Williams pear cultivars are the most susceptible and resistant to Entomosporium, respectively.

Desfolha precoce como estratégia de controle da podridão de Botrytis cinerea na videira Cabernet Sauvignon em regiões de altitude

ABSTRACT Botrytis cinerea is one of the most important pathogens in the highlands of Santa Catarina State. This study aimed to evaluate the influence of different times of leaf removal on the progress of B. cinerea rot in Cabernet Sauvignon grapevine. Assays were conducted in the 2014/2015 and 2015/2016 growing seasons in a commercial vineyard located at 1230m (a.s.l.) in Sao Joaquim Municipality, Santa Catarina State (28o 17’ 39” S and 49o 55’ 56” W). The variety Cabernet Sauvignon was grafted on Paulsen 1103 rootstock, conducted in vertical shooting positioning, 3.0m x 1.5m spacing, and covered with hail protection net. Treatments consisted in leaf removal at the phenological stages: full bloom, Wurz, D.,A., Brighenti, A.F.; Allebrandt, R.; Marcon Filho, J.L.; Bem, B.P.; Araujo Filho, J.V.; Rufato, L.; Kretzschmar, A.A.. Early leaf removal as a strategy to control Botrytis cinerea rot in Cabernet Sauvignon grapevine at high altitude regions . Summa Phytopathologica, v.43, n.2, p.111-117, 2017.