Toxicidade e repelência de extratos de plantas da caatinga sobre Tetranychus bastosi Tutler, Baker &Sales (Acari: Tetranychidae) em pinhão-manso

Abstract

The aim of this study was to evaluate the repellent effect and toxicity of aqueous extracts of M. urundeuva All Br. (Anacardiaceae), Croton blanchetianus Baill( Euphorbiaceae ) and Ziziphus joazeiro Mart. (Rhamnaceae) on the mite Tetranychus bastosi Tutler, Baker & Sales associated with Jatropha curcas. For each extract, the concentrations used were 0, 5%, 10 %, 15 %, 20% and 25%. It was evaluated, at a nochoice test, the mortality of adult females of T. bastosi submitted to different concentrations of each extract. The experimental design was completely randomized with six treatments (control and concentrations of the extracts) and 10 repetitions. The data were subjected to regression analysis. The repellent effect of the extracts over the T. bastosi, in the concentrations already mentioned was also evaluated. The repellency index, percentage repellency, classification and safety index were assessed. The data of percentage repellency of adults in treatment and control were analyzed by the T test Student a 5% probability. In general, the extracts showed toxic effect on adults of T. bastosi for the concentrations tested. The extract of Z. joazeiro indicated d the highest average mortality rates (90 %) of individuals. Regarding the repellency of these extracts, all treatments have proved to be repellants for the females of T. bastosi classified as repellent treatment, except for the 5% dose of the extract of M. unrundeuva.