The pathogenicity of Metarhizium rileyi FJMR2 to different age classes of Spodoptera frugiperda
Author of the article:DING Xue-Ling；YAO Feng-Luan；ZHENG Yu；ZHAO Jian-Wei；LU Xue-Song；WANG Zhu-Hong；HE Yu-Xian
Author's Workplace：Institute of Plant Protection, Fujian Academy of Agricultural Science, Fujian Key Laboratory for Monitoring and Integrated Management of Crop Pests, Fujian Engineering Research Center for Green Pest Management, Fuzhou 350013, China; College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
Key Words：Metarhizium rileyi; Spodoptera frugiperda; insect states; pathogenicity; biological control
Abstract：
[Objectives]
To evaluate the potential of Metarhizium rileyi FJMR2 as a biocontrol agent
for Spodoptera frugiperda. [Methods] The
pathogenicity of FJMR2 to the larvae, pupae and eggs of S. frugiperda was tested using the
leaf dipping method under laboratory conditions. [Results]
A spore concentration of 2×108 spores/mL
achieved a corrected mortality of 1st to 5th instar larvae
and pupae of 100%, 95.78%, 87.15%, 64.67%, 38.00% and 93.93%, respectively. LC50 values of 1st to 5th instar larvae and pupae were 3.12×104, 7.94×104,
2.13×107, 7.46×108 and 1.25×105 spores/mL,
respectively. LT50 values decreased with increasing spore
concentration and increased with larval instar. At a spore concentration of
2×108 spores /mL, LT50 values of 1st to 5th instar larvae and pupae were 3.93, 4.32,
5.62, 7.19, 9.41 and 4.45 d, respectively. In addition, the hatching rate of
0-hour-old eggs and 24-hour-old eggs were 84.53% and 89.77%, respectively, and
the survival rates of newly hatched larvae inoculated with FJMR2 were 1.81% and
3.02%, respectively; significantly lower than that of the control. [Conclusion]
The FJMR2 strain was highly pathogenic to 1st to 4th instar larvae and pupae of S. frugiperda, reducing both the hatching rate of eggs and the survival rate
of newly hatched larvae. It consequently has high potential as a biological control for S. frugiperda.