Grape skin attractiveness of different cultivars of Vitis vinifera to the attack of the grapevine moth (Lobesia botrana Denis & Schiffermüller)

• Autor(a) principal: Teixeira, Victoria Vaz Alves
• Data de Publicação: 2023
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: https://hdl.handle.net/10348/12130
• topic: Vitis vinifera; Lobesia botrana

The vineyards (Vitis vinifera) from the Douro Demarcated Region (DDR) are of great economic and social importance and have the European Grapevine Moth (Lobesia botrana) as the main antagonistic insect. Adults are brown-colored moths that lay eggs in reproductive organs like flower buds and fruits, and after hatching, caterpillars cause damage by feeding on these structures. To improve the management of the European Grapevine Moth in the vineyards of the Douro Demarcated Region, this study aims to 1) quantify the wax extracts of healthy and attacked berries; 2) identify differences between skin waxes of healthy grapes and those attacked by European Grapevine Moth; 3) recognize differences between wax extracts from different grape varieties. To investigate the possible attractiveness of the grapevine berry wax on the incidence of European Grapevine Moth attack in five grapevine cultivars (the reds cultivar Sousão, Tinta Barroca, Touriga Franca, and Touriga Nacional, and the white cultivar Arinto), the determination of the percentage of wax extracts in attacked and non-attacked grape berries and an infrared spectrophotometer analysis of the wax extracts were done. The study was carried out in the Food&Wine laboratory facilities of the University of Trás-os-Montes and Alto Douro. Attacked and non-attacked berries from the same bunch were analyzed, as well as berries from non-attacked bunches that were next to the attacked ones, to compare the respective waxes in each situation. The berry wax was extracted by using chloroform (CHCl3). The percentage of wax extract data were submitted to a two-way ANOVA followed by LSD post-hoc test. The results showed that attacked berries have a bigger percentage of extracts, and no statistically significant difference was found between non-attacked berries from the same bunch compared to non-attacked from the bunch by the side. In reference to the cultivars, Touriga Franca was the one with the minor percentage of extracts, followed by Sousão (both differed with statistical significance from all other cultivar) while Touriga Nacional, Tinta Barroca and Arinto did not differ statistically. The data obtained from the infrared spectrophotometer analysis was submitted to an Orthogonal Partial Least Squares-Discriminant Analysis (OPLS-DA) where differences between treatments were found in the wave lengths between 1550 and 3550 cm-1 , related to the relative content of free fatty acids and esters, and are likely to be related either to the initial composition of the film component lipid material or to be the result of the action of European Grapevine Moth on the composition of the waxes.