Natural occurrence of Beauveria bassiana (Ascomycota: Hypocreales) infecting Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) and earwig in eastern DR Congo

Abstract

AbstractBackgroundThe fall armyworm (FAW),Spodoptera frugiperda(J. E. Smith) (Lepidoptera: Noctuidae), poses a threat to the food security of populations in sub-Saharan Africa because of its damage to maize crops. As alternative to the use of hazardous pesticides, microbial control is one of the most promising sustainable approaches adopted to limit the damages caused byS. frugiperda. The sampling targeted mainly larvae ofS. frugiperda; however, during the survey, cadavers of earwig found on the same sampling sites were also collected and involved in the study. Cadavers of targeted insects, with and without sign of fungal infection, were sampled from 3 localities in eastern DR Congo. Culture of fungal isolates was performed in selective Sabouraud dextrose agar media.ResultsMorphological study of fungal features such as conidia (shape and size) and conidiophores showed that the isolates were from the genusBeauveria. Conidial measurements were highly variable and ranged from 2.4 to 3.6 µm in length and from 1.75 to 3.0 µm in width. Molecular characterization and phylogenetic analysis of the 2Beauveriaisolates based on DNA sequencing of ITS-5.8S region confirmed that both isolates belong toBeauveria bassiana. The 2 isolates ofB. bassianaP5E (OP419735.1) and KA14 (OP419734.1) were isolated from cadavers of FAW and earwig, respectively. The alignment with different sequences ofB. bassianafrom different continent showed that P5E belonged to the same clade of previous isolates reported from Iran and Mexico, while KA14 was with the same clade as isolates from Kenya and China.ConclusionTo our knowledge, this is the first study reporting the occurrence ofB. bassianainfecting FAW and earwig in eastern DR Congo and in Africa.