Management of Fall Armyworm, <i>Spodoptera frugiperda</i> in Sweet Corn with Different Intercrops in Indonesia

Spodoptera frugiperda (J.E. Smith), commonly known as the fall armyworm, represents a significant threat to global corn (Zea mays L.) production. This study evaluated the efficacy of intercropping sweet corn (Z. mays) with basil (Ocimum basilicum L.), lemongrass [Cymbopogon citratus (DC) Stapf] and turmeric (Curcuma longa L.) to manage S. frugiperda infestations. A field experiment, conducted at Jambi University, Indonesia, in 2022, compared Z. mays monoculture to these intercropping systems using a replicated design. The study assessed plant attack rates, leaf damage, cob damage, and larval populations, with statistical analysis performed using t-tests. The results demonstrated that intercropping significantly reduced S. frugiperda infestations. Zea mays monoculture exhibited the highest percentages of attacked plants (47.22% at 4 weeks after planting) and cobs (18.91%), along with the greatest leaf damage (13.89% at 3 weeks after planting) and larval populations (16 larvae at 9 weeks after planting). Conversely, O. basilicum intercropping consistently showed the lowest infestation rates, with minimal leaf damage (0.00% at 2 and 3 weeks after planting) and cob attacks (2.22%). Cymbopogon citratus and C. longa intercropping also reduced pest pressure, though less effectively than O. basilicum. These findings indicate that O. basilicum, C. citratus, and C. longa are repellents to S. frugiperda, making them suitable for sustainable pest management. This study highlights the potential of intercropping with repellent plants as an effective and environmentally friendly strategy for S. frugiperda control in Z. mays, offering a viable alternative to chemical pesticides.