Population of indigenous yeast strains from Prieto Picudo grapes in different growing areas of Denomination of Origin «Tierra de León»

Abstract

In order to analyze the efficacy of the 4 types of fungus preparation based on the Beauveria bassiana spores on the adult populations of grape phylloxera an experiment arranged in a randomized complete block design with three replications was organized in the greenhouse conditions. There were taken into study two grapevine varieties, Cabernet Sauvignon and Feteasca alba. The efficiency of bioproducs was determined based on the results regarding the period of the persistence and the viability of conidia on the leaves after the treatments, the period of the virulence of bioinsecticides and their insecticidal capacity. The conidia of Beauveria bassiana persisted on the leaves surface and infected the larvae and adults of phylloxera for a period of minimum six days, depending of the bioinsecticide composition. The chemical insecticides caused a stronger and faster lethality in comparison with the fungal biopreparations, the high larval mortality of 90.7% being recorded during the first two days from the treatment. After six days, the rate of lethality caused by the variant of bioinsecticide represented by conidial suspension added with 1% glycerol and 1% canola oil was similar to that produced by chemical preparation. Repeated application of the bioinsecticides based on the Beauveria bassiana can cause a significant reduction of the Phylloxera population and it could replace the chemical treatment. Keywords: