Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Screening of a Metarhizium rileyi strain and its virulences to Spodoptera frugiperda (Lepidoptera: Noctuidae).

Abstract

It is crucial for green prevention and control of Spodoptera frugiperda to collect and screen biocontrol strains with high virulence against S. frugiperda. In this study, a fungus was isolated from diseased larvae of S. frugiperda collected in Nanning, Guangxi. The species was identified using morphological characterization and ITS-rDNA sequence analysis, and the pathogenicity of the strain to the larvae, prepupa, and pupa of S. frugiperda were determined by immersion method in the laboratory. The pathogen was identified as Metarhizium rileyi, named CDTLJ1, could infect the larvae, prepupa, and pupa of S. frugiperda. The 1.20×107 conidia/mL concentration treatment caused 100%, 100%, 100%, 100%, 98.33%, 28.33%, and 20.00% corrected mortality of 2nd, 3rd, 4th, 5th and 6th instar larvae, prepupa, and pupa on the 6th day post treatment, and resulted in median lethal time (LT50) values of 3.91 d-4.24 d for the 2nd to 6th instar larvae. The mortality rate of the 3rd instar larvae caused by infection of M. rileyi strain CDTLJ1 increased with the rising of concentration of conidial suspension. When the concentration reached 1×108 conidia/mL, LT50 was 4.10 d, the corrected accumulative mortality reached 100% and the median lethal concentration (LC50) was 1.12×104 conidia/mL on the 6th day post treatment. These results show that the M. rileyi strain CDTLJ1 has a high biocontrol potential for use against S. frugiperda and deserves further research and utilization.