Tratamento preservativo de nim (Azadirachta indica A. Juss) em diferentes níveis de umidade por substituição da seiva.

Abstract

In this study, the penetration, distribution and retention of the preservative chromate copper borate (CCB) in neem pieces (Azadirachta indica A. Juss.), submitted to the sap replacement method, was evaluated. Eight logs were randomly selected, which were subdivided into two groups of similar diameters in order to be submitted to the immunization process under two situations. In the first situation, called "Immerse", the pieces were kept immersed in water for 15 days before being placed in the preservative solution. In the second situation, called "Immediate", the pieces were submitted to the preservative solution immediately after slaughter. After the end of the immunization process discs were removed along the parts, taking as reference the base, the medium and the top. In each of these positions, three discs were taken for the evaluation of the parameters of penetration, distribution, retention and for the biological test to termites. For analysis of penetration and distribution were determined by colorimetric reactions, being evaluated the elements boron and copper. Retention analyzes for the boron element were performed by spectrophotometry. For the biological test, four termite mounds were pre-selected, and the test specimens were evaluated twice during the field test period. Data were submitted to analysis of variance (F test), with data transformation and nonparametric test use when necessary (Kruskal-Wallis). In all cases, a 5% probability of error was considered. With the mean penetration values of 14.14 mm in the immediate situation and 15.56 mm in the immersed situation and for the retention with the mean values of 0.51 kg ai/m³ in the immediate situation and 0.61 kg ai/m³ In the immersed situation, it was possible to conclude that the trunks kept submerged before being submitted to the preservative treatment showed a significant improvement in their treatability, as well as repellency to xylophagous termites.