Toxic potential of Melia azedarach leaves extract against Odontotermes obesus and Microtermes obesi

Abstract

The termites are small insects (order: Isoptera, class: Insecta), world widely distributed but their infestation cause a loss of billions of dollar each year in a single country. The two termite species Microtermes obesi and Odontotermes obesus are commonly found in Pakistan and for the present study, were collected from the locality of Quaid-i-Azam University Islamabad in the month of June 2013. The extracts in water and methanol solvent with varying concentrations (100ppm, 200ppm, 300ppm) of Melia azedarach were tested against both termite species selected. 40 termite workers were placed in each petri dish having filter paper soaked in every concentration of extract taken in each solvent. Mortality of termites and LC50 and LC90 was calculated after each 24, 48 and 72 hrs of the experiment compared with day zero and found to be 0.002 and 0.007 % in water solvent and 0.0003 and 0.0004% after 72 hrs in methanol solvent against O. obesus respectively. Similarly LC50 and LC90 value against M. obesi after 72 hrs were found to be 0.001 and 0.009% in water solvent and 0.002 and 0.008% in methanol solvent. The results were analyzed by using one way ANOVA and Tukey test. Total carbohydrate (mg/g), lipid mg/dl (triglyceride, cholesterol and high density lipid) and Protein (mg/g) contents of dead termites were estimated by Lowry’s method, phenol sulphuric acid method and by biochemistry analyzer. Carbohydrate, lipid contents were decreased and protein contents of both the termite species was increased as compared to control. The change in these biochemical components may be due to the insecticidal stress caused by these extract which lowered the feeding, proper digestion of food and metabolism. The M. azedarach leaves extract were found to be toxic for both termite species. The active component can be characterized and isolated by GCMS for commercial use.