Repelência e mortalidade de Sitophilus spp. exposto a pó vegetal de eucalipto (Eucalyptus dunii)

Abstract

The objective of this research was to evaluate the repellent and insecticidal action of stored and fresh dust from different plant structures: leaves, bark, wood and ash, of the species Eucalyptus dunnii on Sitophilus spp. in the concentration of 0.4 g of powder of each plant structure of E. dunnii to 20 g of corn seeds. In the repellency tests, arenas composed of three acrylic Petri dishes were used, interconnected by plastic tubes between them, so that the insects chose between the sample of treated maize or the control. 30 insects per sample were used. The evaluation was performed 24 hours after the installation of the experiment where the counting and sexing of the individuals in each container were carried out. In the mortality tests, 20 non-sexed adults were released in acrylic Petri dishes containing corn seeds treated with the different treatments and the control. The evaluation was performed daily, during 10 days, with the daily counting and sexing of the dead insects. The experimental design was a completely randomized design, with 5 treatments and 5 replicates. Also, two bioassays were performed, with the same tests for different times of use of the powder. The data collected were submitted to analysis of variance (ANOVA) and the differences between averages compared by the Tukey test at 0.05 of significance for the mortality tests and by the ta 0.05 test of significance for the repellency test, through the program Sisvar®. As a result, stored and fresh leaves and bark powder and fresh ash were found to have repellent for Sitophilus spp. and only gray treatment was effective for insect control, with mortality rates above 85% for the two times of use of the powders.