Pathogenic Assessment of SfMNPV-Based Biopesticide on Spodoptera frugiperda (Lepidoptera: Noctuidae) Developing on Transgenic Soybean Expressing Cry1Ac Insecticidal Protein

Abstract

Pathogenic assessment of a baculovirus-based biopesticide containing Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV: Baculoviridae: Alphabaculovirus) infecting fall armyworm, Spodoptera frugiperda (J. E. Smith, 1797) (Lepidoptera: Noctuidae) is reported. In the bioassays, neonates were infected with different doses of SfMNPV applied on Cry1Ac Bt soybean and non-Bt soybean. Our findings indicated that S. frugiperda neonates did not survive at 10 d post infection or develop into adults on Bt and non-Bt soybean sprayed with the field recommended dose of SfMNPV. In contrast, a proportion of the infected neonates developed into adults when infected with lower doses of SfMNPV (50%, 25%, and 10% of field dose) in both Bt and non-Bt soybean. However, S. frugiperda neonates surviving infection at the lowest virus doses on both soybean varieties showed longer neonate-to-pupa and neonate-to-adult periods, lower larval and pupal weights, reduced fecundity, and increased population suppression. Nevertheless, more pronounced pathogenicity of SfMNPV infecting neonates of S. frugiperda were verified on larvae that developed on Bt soybean. These findings revealed that, beyond mortality, the biopesticide containing SfMNPV also causes significant sublethal pathogenic effects on neonates of S. frugiperda developing on Bt and non-Bt soybean and suggested an additive effect among SfMNPV and Cry1Ac insecticidal protein expressed in Bt soybean.

Sub-lethal effects of indigenous isolate of Spodoptera frugiperda nucleopolyhedrovirus on fall armyworm growth and reproduction in India

“…Though a number of studies have been investigated and analyzed the debilitating effects associated with baculoviral infections, the severity of the observed effects appeared to be partly influenced by the species or strain of the infecting baculovirus (Akhanaev et al 2020). Limited studies have monitored the effect of S. frugiperda nucleopolyhedrovirus on surviving populations of the FAW (Zakseski et al 2021). In this regard, the sublethal effects of indigenous strain of SpfrNPV isolated from Chikkaballapura district, Karnataka on FAW population, in India, was observed.…”

Control Potential of Multiple Nucleopolyhedrovirus (SfMNPV) Isolated from Fall Armyworm in Nigeria (West Africa)

“…This can cause host death after 6 to 8 days post ingestion. A caterpillar infected with nucleopolyhedrovirus declines in feeding ability and eats only 7% of the food normally consumed by a healthy caterpillar [4,13]. The symptoms of Baculovirus infection include the appearance of blemishes and yellowing of the skin.…”