Pest Management Science (2022) 78, 1146-1154

Marcos Faria, Daniela Aguiar Souza, Marcio Martinello Sanches, Francisco Guilherme Vergolino Schmidt, Charles Martins Oliveira, Norton Polo Benito and Rogerio Biaggioni Lopes (2022)
Evaluation of key parameters for developing a Metarhizium rileyi-based biopesticide against Spodoptera frugiperda (Lepidoptera: Noctuidae) in maize: laboratory, greenhouse, and field trials
Pest Management Science 78 (3), 1146-1154
Abstract:
BACKGROUND
The entomopathogenic fungus Metarhizium rileyi is known to cause natural infections in some caterpillars. In this multiyear study, we carried out laboratory, greenhouse and three field trials with the aim of developing a sustainable option for control of the fall armyworm (FAW) in maize. Association of M. rileyi with Spodoptera frugiperda baculovirus (SfMNPV) and delivery strategies were also investigated.
RESULTS
The selected isolate (CG381) was effective in the laboratory at a low concentration (~ 4 × 10³ conidia cm^-2), killing >95% of FAW larvae within 8 days. In the greenhouse assay, applications of conidia suspended in water or as dry powder in maize whorls (~ 6.3 × 10⁶ conidia per plant) produced similar larval mortalities (88%–96%). In the field trials, conventional spraying of unformulated conidia (0.6 and 1.2 × 10¹² conidia ha^-1) caused low larval mortalities (27–31%). Simultaneous application of either unformulated or oil-based formulations of M. rileyi conidia and S. frugiperda baculovirus (SfMNPV) to plant rows caused larval mortalities comparable with each of the pathogens applied alone. However, when a formulation containing both pathogens was sprayed directly into the whorls, the overall mortality of S. frugiperda larvae due to pathogens (mostly to M. rileyi infections) reached ~ 59%, twofold higher than the other treatments with conventional spraying, whereas in the control, the overall mortality was only 1%.
CONCLUSION
Optimizing exposure of S. frugiperda larvae to an inoculum of virulent entomopathogens through directed applications to maize whorls is critical to produce satisfactory mortality levels and is promising for integrated pest management.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Marcos R. de Faria, Marcio Martinello Sanches, Charles Martins de Oliveira

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
evaluation - screening - selection

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Spodoptera frugiperda	Maize/corn (Zea mays)	Brazil (south)
Metarhizium rileyi (entomopathogen)	Spodoptera frugiperda	Maize/corn (Zea mays)	Brazil (south)
Alphabaculovirus spofrugiperdae (entomopathogen)	Spodoptera frugiperda	Maize/corn (Zea mays)	Brazil (south)