Evaluation of a New Entomopathogenic Strain of Beauveria bassiana and a New Field Delivery Method against Solenopsis invicta

PLoS One. 2016 Jun 24;11(6):e0158325. doi: 10.1371/journal.pone.0158325. eCollection 2016.

Abstract

Solenopsis invicta Buren is one of the most important pests in China, and control measures are mainly based on the use of synthetic pesticides, which may be inadequate and unsustainable. Hence, there is a growing interest in developing biological control alternatives for managing S. invicta, such as the use of entomopathogenic fungi. To facilitate the commercialization of entomopathogenic fungi against S. invicta, 10 Beauveria bassiana isolates originating from different hosts were tested for virulence in laboratory bioassays, and the most pathogenic strain, ZGNKY-5, was tested in field studies using an improved pathogen delivery system. The cumulative mortality rate reached 93.40% at 1×108 mL-1 conidia after 504 h. The germination and invasion of the spores were observed under a scanning electron microscope, and several conidia adhered to the cuticle of S. invicta after 2 h. Furthermore, the germ tubes of the conidia oriented toward the cuticle after 48 h, and the mycelium colonized the entire body after 96 h. Based on the efficacy observed in the laboratory trials, further experiments were performed with ZGNKY-5 strain to evaluate its utility in an injection control technology against S. invicta in the field. We found that three dosage treatments of ZGNKY-5 strain (500 mL, 750 mL, and 1,000 mL per nest) had significant control effects. Our results show that this strain of Beauveria bassiana and our control method were effective against S. invicta in both laboratory and field settings.

MeSH terms

  • Animals
  • Ants / microbiology*
  • Beauveria / physiology*
  • Beauveria / ultrastructure
  • Insect Control*

Grants and funding

This research was supported by the Guangdong Provincial Department of Science and Technology (2016A020223010), Science and Information Technology Bureau of Guangzhou (2014J4100211), Funds for Environment Construction & Capacity Building of the GDAS' Research Platform (2016GDASPT-0305, 2016GDASPT-0215), and the Shenzhen Wild Animal and Plant Protection Administration Agent. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.