Atividade biológica do vírus SFMNPV em spodoptera frugiperda em laboratório e validação da aplicação aérea com drone pulverizador em milho

Abstract

Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae) is naturally distributed in tropical and subtropical areas but reported in several regions worldwide. It is a polyphagous pest that has 357 plants as hosts, attacking mainly crops such as soybeans (Glycine max L.), corn (Zea mays L.), and cotton (Gossypium hirsutum L.), responsible for damaging the production chain, causing severe economic damage to plantations. Recently, the use of bioproducts for the management of S. frugiperda has been recommended to avoid the indiscriminate use of synthetic chemicals, which generate adverse disturbances in the agroecosystem, in addition to being the main responsible for high levels of resistance from S. frugiperda. The present study aimed to evaluate the laboratory and field mortality of S. frugiperda exposed to different concentrations of Baculovirus Spodoptera Multiple Nucleopolyhedrovirus (SfMNPV) and determine the lethal concentrations of 50 and 90%. Part of the study was conducted at the Entomology Laboratory and part at the Experimental Station, both belonging to the Federal University of Paraíba- PB. A completely randomized experimental design (CRD) was adopted to experiment in the laboratory with eight treatments and 25 replications. For the field experiment, a randomized block design (RBD) was adopted the varieties used were Robusto and Jabatão, one corn seed per hole, at a sowing depth of 2-3 cm and a spacing of 0.3 meters between the plants and 0.8 meters between the lines, each experimental strip was 20 meters wide and 120 meters long, the treatments consisted of the application of Cartugen®, which contains SfMNPV baculovirus (7.5 x 109 occlusion bodies/mL) and just water, in the laboratory the product was applied via manual spraying and in the field via Drone T40. According to the concentrations of Cartugen® evaluated, the effectiveness of SfMNPV is proven as we found the LC50 at 8320 ppm (IC95%= 7168 – 9920 ppm) and LC90 at 20960 ppm (IC95%= 15968 – 32960 ppm), as well as when validated in the field at LC50 in both varieties, the virus negatively impacted the population dynamics of the pest. However, the impact was more significant in the Robusto variety, with a population reduction significantly more critical than the other conditions, with a population decrease of up to 90% (-0.9052). In the Jabatão variety, the population reduction varied between 13 and 37%, showing the effectiveness of Cartugen®. This approach represents a significant advance towards the development of yet another more sustainable, effective, and economically viable management strategy, bringing long-term benefits to the management of one of the most destructive pests in the world, S. frugiperda.