Análise faunística, caracterização de injúrias e efeito repelente de azadiractina e vespas sociais (Hymenoptera: Vespidae) em parreiras do município de Bento Gonçalves, Rio Grande do Sul.

Abstract

Rio Grande do Sul is the major producer of grapes for winemaking in Brazil, highlighting the Serra Gaúcha as the main producing region. In the persuit of good quality grapes that provide good profitability, a key aspect to be noted is the occurrence and control of pests, especially insects. This work highlights the incidence of wasps, which cause serious damage at harvest time. Due to the lack of food during the summer, these insects end up going to the maturing grape bunches. Accordingly, this study aimed to characterize the community of social wasps and relationship of these with injuries to the fruits, as well as evaluate the repellency of azadirachtin on wasps in vineyards of Bento Gonçalves, RS. The collections were made by active search in January and February 2014, and the individuals captured were identified based on morphological characters. From the data obtained faunal community analysis was performed. The injuries have also been observed in berries to assess exactly which species are responsible for disruptions of bark. Finally, as alternative to drive away these insects and avoid the occurrence of this problem a test of repellency with azadirachtin was performed at a concentration of 1.2 g/100L active ingredient, this organic compound and without grace period.Ten species of wasps able to use the grape berries as food were identified. The two predominant species were Polybia ignobilis and P. minarum. It was found that Synoeca cyanea has the ability to break the intact berries. Other three species, Polistes cavapytiformis, P. versicolor e Brachygastra lecheguana, were also able to break the peel, but in berries with already impaired health conditions. Tests with azadirachtin did not show repellency and was not found significant reduction of wasps and bees in the vineyard after application.