Silicon Accumulation in Leaves Reduces the Herbivory by Invasive Fall Armyworm Spodoptera frugiperda and Enhances the Yield of Maize

Fall armyworm (FAW) Spodoptera frugiperda is currently being considered as a serious insect pest in maize that causes significant yield losses worldwide. Silicon (Si) and plant growth regulators (PGRs) are known to induce resistance against biotic and abiotic stresses thereby enhancing the yield. This study was conducted to determine the influence of Si and PGRs on the incidence and damage of FAW on maize (Zea mays L.) under field condition. The experiment was conducted in both Kharif and Rabi seasons using a randomized complete block design with three replications and treatments. Various combinations of foliar silicic acid (FSA) and two PGRs such as gibberelic acid (GA3) and jasmonic acid (JA) were tested to study their effects on FAW incidence and maize yield. The application of FSA at 2mL/plant + GA3 at 0.5 mg/plant recorded the lowest number of larvae per plant (0.39 larva/plant) with the lowest damage score of 2.55 (Davis scale). The percent infestation was also low for the same treatment, i.e., 34.14 percent infestation with the highest percent reduction over control (56.43%). The highest yield (58.39 q/ha) and cost–benefit ratio (1:2.34) was recorded for FSA at 2 mL/plant + GA3 at 0.5 mg/plant, which was considered as the best treatment. This study demonstrated that exogenous application of Si along with PGRs has significant negative effect on field incidence of FAW and enhanced the yield of maize.