TERMICIDAL EFFECTS OF Azadirachta indica (A. JUSS) ON Danielia oliveriand Ficus exasperataWOOD SPECIES

Abstract

ABSTRACT Wood as a renewable bio-resource is susceptible todegradation by biological agents such as termites which can be controlled by plant extracts. This study assessed the termicidal effects of bark and leaf extracts of Azadirachta indica on Danielia oliveriand Ficus exasperatawood species. Green board of D. oliveriand F. exasperatawere processed into 40 samples each, with a dimensionof 45 mm × 35 mm × 35 mm and oven dried to moisture content of 12% ±3. Azadirachta indica leaf and bark extracts were prepared by mass/volume ratioto derive 0.1, 0.075, 0.05 and 0.025 % concentrations. The wood samples were soaked in theextracts for 24 hours and incubated in the termitarium for 16 weeks. Parameters assessed in this study were density (D), preservative absorption (PA), preservative retention (PR),visual assessment (VA) and weight loss (WL). Data collected were subjected to Analysis of Variance, while means were separated with Duncan Multiple Range Test at p≤0.05. There was a significant difference in the D, PA, PR and WL of D.oliveriand F. exasperatawood samples. The concentrations of bark and leaf extracts of Azadirachta indica had significant difference in the PR and WL of D. oliveriand F. exasperatawood samples. Treated D. oliveriwood had the highest D of 1.09±0.12 g/cm3, while F. exasperata had the lowest D with a mean value of 0.75±0.06 g/cm3. D. oliverihad the highest PA (89.71±11.02) of leaf extracts at 0.075% concentrations and lowest (31.63±19.69) in F. exasperatawood at 0.075% concentrations. D. oliveriwood had the highest PR of leaf extracts at 0.1% concentration, while F. exasperataat 0.025% leaf extracts had the lowest values with 88.24±15.73 and 12.92±4.57 respectively. Visually, D. oliveriwood were badly damaged, while F. exasperatawood were fairly damaged at the end of the experiment. The WL increased as the extracts concentration decreased. The highest WL of the treated wood was 70.92±7.75 in D. oliveritreated with 0.025% bark extracts, whileF. exasperatatreated with leaf extracts at 0.1% gave the lowest WL (12.97±2.85). Plant extracts used in this study had significant impacts on the termite control at 0.1 % and 0.075 % concentrations. This study concluded that, leaf and bark extractsofAzadirachta indica at 0.1 and 0.075 % concentrations were able to control termites attack on wood. The use of plant extracts in elongating the life span of wood and ensuring protection of the environment from chemicals is recommended.