THE INVENTION PROVIDES NATURAL BIOPESTICIDE THAT IS CAPABLE OF TREATING AGRICULTURAL CROPS AGAINST PEST AND IS USEFUL AS ANTIFEEDANT AGENT IN AGRICULTURAL PLANTS SUCH AS. THE INVENTION FURTHER PROVIDES METHODS DESCRIBING THE TREATMENT OF PEST BY ADMINISTERING TO THE AGRICULTURAL PLANTS AN EFFECTIVE AMOUNT OF THE ANTIFEEDANT AGENT, EITHER ALONE OR IN COMBINATION WITH ANOTHER BIOPESTICIDE AGENT. ACCORDINGLY, A METHOD OF PREPARING THE COMPOSITION FOR DECREASING THE POPULATION OF PEST IN AGRICULTURE CROPS OBTAINED FROM LEAVES OR STEMS OR MIXTURE OF LEAVES AND STEMS OF CENTELLA ASIATICA PLANT, THE METHOD COMPRISING THE STEPS OF: A) OBTAINING CENTELLA ASIATICA LEAVES OR STEMS OR MIXTURE OF LEAVES AND STEMS, B) DRYING THE OBTAINED LEAVES OR STEMS OR MIXTURE OF LEAVES AND STEMS AT 70°C FOR THREE OR MORE DAYS IN ORDER TO OBTAIN DRIED LEAVES AND/OR STEMS, C) OBTAINING CRUDE EXTRACT(S) BY SUBJECTING THE SAID DRIED LEAVES OR STEMS OR MIXTURE OF LEAVES AND STEMS FROM STEP (B) WITH DICHLOROMETHANE OR MIXTURE OF DICHLOROMETHANE AND METHANOL, D) ISOLATING AND PURIFYING THE SAID CRUDE EXTRACT(S) FROM STEP (C) WHEREIN CONCENTRATIONS OF THE DICHLOROMETHANE (DCM) AND METHANOL (MEOH) MIXTURES ARE OF FRACTION 95% DCM : 5% MEOH IN DICHLOROMETHANE (DCM) EXTRACT 98% DCM : 2% MEOH OR 90% DCM : 1 0% MEOH IN METHANOL (MEOH).