Various synthetic agrochemicals, are inherent to the current agricultural technology development mode. They are primarily responsible for several environmental and health problems in the world. Continuous use of synthetic pesticides develops resistance against some pests and is not a sustainable option to control pests. Therefore, the interest on organic applications is increasing and a need for the possible alternatives for agro chemical usage in agriculture is developing. Hence. a herbal plant of Glycosmis peritaphylla, known as “Dodampana” has been experimentally investigated at the research field at UCIARS, Weligatta, Hambantota, Sri Lanka with the objective of evaluating the Glycosmis pentaphylla leaf extract as an insect repellent for a vegetable crop of Radish. There were four treatments with four replications, comprised of 60 radish plants per each. The treatments were the Dodampana leaf extract, Neem oil mixture, a recommended commercial pesticide containing the active ingredient of abamectin and water as the control. Growth parameters (Number of leaves per plant, Length of leaf (cm), Yield in (kg) and Pest incidence (Number of pest attacked plants, Number of damage leaves by pests, Number of pests identified in experiment unit) were recorded and statistically analyzed using SAS 9.1 statistical software. It was revealed that, there was a significantly higher yield in Glycosmis pentaphylla leaf extract added radish plants compared with control. The values are comparable in Glycosmis pentaphylla leaf extract added plants and Chemical pesticide applied plants. Further, there was a significant reduction of number of pest attacked plants and number of damaged leaves in Dodampana leaf extract added plants compared with control. There was no significant difference in number of pest attacked plants and number of damaged leaves in Glycosmis peritaphylla leaf extract added plants and chemical pesticide applied plants. Therefore, Glycosmis peritaphylla leaf extract could be used as an alternative for chemical pesticide application for Radish.