PREVALENCE AND SEVERITY OF TERMITES ATTACK ON SELECTED INDIGENOUS WOOD SPECIES IN ONDO STATE, NIGERIA

Abstract

The study investigated the severity of termites attack on Celtis zenkeri, Terminalia ivorensis, Albizia lebbek, Cola gigantia and Terminalia superba using three locations: Okitipupa, Akure and Akungba Akoko in Ondo State, Nigeria in order to establish its prevalence. Macrotermes bellicosus was the termite species present in Okitipupa, Macrotermes sybhylinus was identified in Akure while Odontotermes horni (wasmann) was found in Akungba Akoko. Density of the selected wood species was determined and classified into high, medium and low density. Weekly visual observations of the stakes were carried out as specified in ASTM D3345-80 Standards for 12 weeks. The wood samples were withdrawn after 12 weeks of exposure to termites and weight loss due to termites’ attack was estimated. Results obtained showed the relationship between wood density, weight loss and ASTM ratings in the three locations of studies. The results of the correlation between wood density and percentage weight loss; and wood density and ASTM visual rating in Okitipupa revealed that no correlation exist between them. It indicated that there was no relationship between them. In Akure, a moderate negative correlation existed between wood density and weight loss, this implied that the higher the density of the wood the lower the percentage weight loss. Where there is weak and positive correlation between wood density and ASTM, this implied that increase in wood density will lead to increase in ASTM Visual Rating. Also Akungba showed that a moderate and negative correlation exist between wood density and weight loss , this implied that the higher the density of the wood the lower the weight loss while there is also a moderate and positive correlation between density and ASTM, this implied that increase in wood density will lead to increase in ASTM Visual Rating. It was observed that the difference in the termites species and the physical properties of the soil in the locations of studies bring about the difference in the correlation between wood density and termites resistance. These results indicated that wood species in the high density class had a better resistance to termites’ attack in Akure and Akungba. It was also observed that there was significant difference in the severity of termites attack in the three locations. With Akure recorded the highest degree of attack by termites followed by Akungba while Okitipupa recorded the least. The field test results also showed that treatment with bitumen greatly increased the resistance of the five wood species to termites attack in the three locations. The ANOVA results indicated that there is significant difference between the resistance of treated and untreated samples at 5% level of significance. From the results obtained, it is evident that bitumen and solignum mixtures at 70:30 is very effective as preservative for protection of wood against termites attack.