Bioatividade de pós de Eucalyptus dunnii para controle de Sitophilus zeamais MOTS (Coleoptera: Curculionidae) em grãos de milho armazenado

Abstract

The insect repellent and insecticidal action of Eucalyptus dunnii different plant parts on Sitophylus zeamais was evaluated. The treatments used were bark powder, leaf powder, wood powder and ash at 2% concentration. For the repellency bioassay, arenas composed of three circular plastic containers (10 cm x 2 cm acrylic Petri dishes) were used, with the central container symmetrically interconnected by two transparent plastic tubes (10cm) arranged longitudinally so that the insect could choose between the treatment and the witness. Twenty insects were used per replicate. The evaluations were performed 24 h after the bioassay implantation, recording the number of insects present in the treatment and in the control. For the mortality bioassay, 20 insects without sex identification were placed in individual acrylic Petri dishes (10 cm) for each treatment and for the control. The evaluations were performed daily for a period of 15 days. After each evaluation, the sex of the dead insects was identified. The experimental design was completely randomized with 5 treatments and 5 replicates each. The data were submitted to analysis of variance and the means were compared by the Tukey test at 5% probability, through the SASM - Agri program. The results showed that the treatments did not exert repellent activity on Sitophylus zeamais and the treatment that caused the highest mortality was that of ash, presenting 79% of mortality after 15 days of evaluation.