Synergistic efficacy of extract of Jatropha curcas seeds and enzyme extract of Serratia marcescens against Spodoptera frugiperda under greenhouse conditions

This study assessed the individual and combined effects of the acetonic extract from Jatropha curcas seeds (EAcJc) and the enzymatic extract of Serratia marcescens (EESm) on foliar damage caused by Spodoptera frugiperda larvae in maize plants under greenhouse conditions. In the first bioassay, maize plants were treated with EAcJc (0, 1000, and 2500 ppm), EESm (0, 150, and 300 ppm), and mixtures of EAcJc + EESm (0, 1000 + 300, and 2500 + 300 ppm) using a completely randomized design. In the second bioassay, the effect of varying application frequencies (0, 2, 3, and 4 times) of the EAcJc + EESm mixture at a fixed concentration of 2500 + 300 ppm was evaluated. By day 12, the treatments with EAcJc at 2500 ppm, EESm at 300 ppm, and the combinations of 1,000 + 300 ppm and 2500 + 300 ppm resulted in significant reductions in foliar damage of 51.5%, 50%, 49.0%, and 46.25%, respectively, compared to the control. Furthermore, the treatment mixture (2500 + 300 ppm) reduced damage by 58.0%, 57.5% and 56.5% after two, three and four applications, respectively. These findings highlight the potential of EAcJc and EESm, individually and in combination, as alternatives to synthetic chemical insecticides in controlling of S. frugiperda larvae.