The objective of this work was to evaluate the efficiency of oils from neem (Azadirachta indica) and castor plant (Ricinus communis) in improving the resistance of Sumauma wood (Ceiba pentandra) to Nasutitermes corniger xylophogous termite under feed preference assay. Oils from neem and castor oil plant were extracted with absolute ethyl alcohol and used in preparing preservative solutions. Wood samples with dimensions of 2.0 × 10.16 × 0.64 cm (radial × longitudinal × tangential) were treated to reach a nominal retention of 10 to 16 kg of solution by m³ of wood, and some treated samples were submitted to the weathering test (volatily and leaching tests). The treated samples were submitted to termites in feed preference assay. Oils from neem and castor oil plant did not contribute much to improvement of Sumauma wood resistance to the tested termite. Among the tested solutions, the pure castor oil plant oil was the most efficient. Weathering of samples little influenced wood resistance. Although neem and pure castor oil plant oils presented some repulsive effect to termites, their effects are not durable, indicating that these products should not be used in wood treatment in order to improve its resistance to xylophogous termites.
Neem and castor oil plant oils; Wood treatment; Xylophogous termites
