Corymbia citriodora leaf extracts in the protection of Eucalyptus sp.

Plant extracts can be a sustainable alternative in the control of wood biodeteriorating agents due to their rich sources of bioactive chemicals. The objective of the study was to evaluate the performance of natural extracts from Corymbia citriodora obtained in different preparation methodologies, as an alternative for the preservation of Eucalyptus sp. Six treatments were used: T0 – control, without treatment; T1 – CCB (Chrome Copper Borate); T2 – Leaves macerated manually and heated to 100 °C; T3 – Leaves macerated manually and immersed in water; T4 – Leaves mechanically crushed and heated to 100 °C; T5 – Mechanically shredded leaves and immersed in water. The impregnation of the treatments in the wood of Eucalyptus sp was carried out in a vacuum pump and later the specimens were partially buried in field simulators with clayey soil of pH 5 (Simulator 1); medium texture with pH 4.5 (Simulator 2); and sandy with pH 5.1 (Simulator 3), where they remained for 180 days. Then, mass loss, visual wear, specific mass, mass gain, volumetric swelling and retention of the preservative solution were evaluated. Soil characteristics in the field simulator did not influence wood mass loss, regardless of preservative treatment. The values ​of specific mass, mass gain, volumetric swelling and retention of the preservative solution showed no statistical difference by Tukey’s test at 5% of significance. Treatment 1 presented results of mass loss of only 2.27%. The materials with extracts showed variations: T2 – 7.86%, T3 – 9.93%, T4 – 8.47%, T5 – 18.84. When comparing with the results of T0 – 18.83%, it is observed that T2, T3 and T4 provided better properties against the soft rot fungus. The methodology applied to Treatment 2 was characterized as the most promising for the conditions of wood preservation in the field.