Evaluation of the Efficacy of Castor Oil as a Biopesticide in the Treatment of Leucinodes orbitalis Guenee L., A Pest of Eggplant (Solanum melongena)

Abstract

Leucinodes orbonalis Guenée L. is a pest of Aubergine. It is currently managed using synthetic chemical pesticides. However, certain plants with insecticidal properties can be used to control Leucinodes orbonalis in aubergines. To study the effectiveness of the castor oil solution, a trial was carried out at the ISAV in Faranah from 08/05 to 20/08/2023. Castor oil was extracted using a press machine with a yield of 0.41 l/kg. Under field conditions, the study involved 80 aubergine plants. The parameters monitored were: incidence of attack, number of plants leafed out and productivity. The survival of Leucinodes orbonalis larvae after treatment was also estimated in vitro. The doses used were: D0 = 0 l/ha (control); D1 = 2.5 l/ha; D2 = 5 l/ha and D3 = 7.5 l/ha. The results showed that the incidence of attack after treatment was 68% for the control. However, this incidence was 10, 4 and 2% respectively for doses D1, D2 and D3. With regard to the number of plants thinned out, the rates were 68% for the control, 33% for D1, 17% for D2 and 8% for D3. Productivity was: 3.0 t/ha for the control; 5 t/ha for D1; 8 t/ha for D2 and 11.02 t/ha for D3. Survival of Leucinodes orbonalis larvae after application of the castor oil solution was 92%, 20%, 10% and 0% respectively for the D1, D2 and D3 controls. Analysis of the results shows that the 7.5 l/ha dose of castor oil is a good biopesticide for controlling Leucinodes orbonalis.