Caracterização do granulovírus SfGV e do seu efeito no controle da lagarta-do-cartucho (Spodoptera frugiperda)

Abstract

The larvae of Spodoptera frugiperda (J.E. Smith, 1797) (Lepidoptera: Noctuidae) are considered one of the most damaging pests in Brazil, as they attack a wide range of crops, such as corn, soybeans, and sorghum. One form of pest management that has been widely used over the years is the use of baculoviruses as bioinsecticides, due to their high specificity, efficiency, and mortality rates. During field trials in northeast Brazil, the company AgBiTech Controles Biológicos LTDA has discovered a S. frugiperda caterpillar infected with a natural granulovirus, which is still unknown. Thus, this study aimed to characterize this new baculovirus, named Spodoptera frugiperda granulovirus (SfGV), and analyze its effect on the infection of larvae of this species. A molecular characterization of the virus was conducted using the restriction fragment length polymorphism (RFLP) method, with the enzymes Bam HI, Eco RI, and Pst I. Bioassays to test the viral activity were performed in duplicates, and treatments with viral particles were diluted into eight different doses. During the bioassay process, the symptoms of the larvae were analyzed and photographed. According to the results, the baculovirus found is a previously undescribed granulovirus that causes a type I infection syndrome, being a slow-kill granulovirus. The SfGV was able to kill 100% of the infected larvae, according with a gradual increase in doses, showingan LT50 of 21 days. Therefore, SfGV demonstrated potential for use in control methods for S. frugiperda.