Alterações bioquímicas em milho exposto à herbivoria de spodoptera frugiperda (lepidoptera: noctuidae) e tratado com preparados homeopáticos

Abstract

Corn (Zea mays Linnaeus) is a species of great economic and social importance, as its grains are predominantly used in animal feed and biofuel production. The fall armyworm (Spodoptera frugiperda) is a species that causes significant losses in biomass and corn grain production. As a primary pest, it is necessary to adopt control strategies that can harmoniously reduce populations and, consequently, the damage. The use of natural substances, such as homeopathic preparations, constitutes a practice compatible with integrated pest management programs. Homeopathic and isotherapeutic preparations can act as inducers of plant resistance to insects without toxic effects. This study evaluated the biochemical response of corn plants treated with homeopathic preparations of the S. frugiperda caterpillar at potencies of 6, 12, 15, and 18 CH (Centesimal Hahnemannian) and exposed to herbivory by S. frugiperda caterpillars. The corn plants were grown in 3 L pots in a climate-controlled greenhouse and treated with homeopathic preparations via irrigation in the pots. After reaching the V3 stage, they were infested with 4th instar S. frugiperda caterpillars and maintained for 7 days for subsequent biochemical evaluation of the corn leaves. The above-ground part of the corn plants was collected before and after herbivory, and the biochemical parameters evaluated were protein, guaiacol peroxidase (POD) enzyme, and phenylalanine ammonia-lyase (PAL). The applications of the homeopathic preparations of S. frugiperda (6, 12, 15, and 18 CH) increased the concentration of proteins and the activity of the guaiacol peroxidase enzyme after the 7- day infestation. It was evidenced that the homeopathic preparations of S. frugiperda caterpillars help in inducing the resistance of corn plants to the damage caused by herbivory.