2.4. Ovicidal assayOvicidal activity was studied following the method of Elango et al [27]. Twenty five freshly laid eggs of Ae. aegypti and Cx. quinquefasciatus were separately exposed to four different concentrations, namely 62.5 parts per million (ppm), 125 ppm, 250 ppm, and 500 ppm, prepared using acetone. Each concentration was replicated five times. Control (acetone in water) was maintained separately and egg mortality was observed under the microscope. Azadirachtin (10 ppm) and temephos (10 ppm) were used as positive controls for comparison with five replications each. The percent ovicidal activity was assessed at 120 hours post-treatment using the following formula: