Infection of Beauveria bassiana and Cordyceps javanica on different immature stages of Duponchelia fovealis Zeller (Lepidoptera: Crambidae)

• Published in: Crop protection 2020-12, Vol.138, p.105347, Article 105347
• Main Authors: Baja, Franciele, Poitevin, Carolina G., Araujo, Emily S., Mirás-Avalos, José M., Zawadneak, Maria A.C., Pimentel, Ida C.
• Format: Article
• Language: English
• Subjects: Biocontrol agent; Electron microscopy; Entomopathogenic fungi; European pepper moth; Fragaria x ananassa; Virulence
• ISSN: 0261-2194
• DOI: 10.1016/j.cropro.2020.105347

Entomopathogenic fungi (EPF) can be viable options for biological control of agricultural pests. The selection of fungal strains is crucial for a successful pest control. The current study aimed to determine in the laboratory the susceptibility of different immature stages of Duponchelia fovealis Zeller (Lepidoptera: Crambidae) to EPF strains (Beauveria bassiana Bea111 and Cordyceps javanica Isa340). Immature stages of D. fovealis were sprayed with EPF concentrations from 2 × 103 to 2 × 109 conidia mL−1 and their viability and mortality were evaluated. Lethal time and concentration were estimated for pupae and each larval instar. Virulence depended on strain, dose, and insect life stage. The eggs were resistant to Bea111 and Isa340 strains. Mortality of larvae depended on the EPF strain and the larval instar, with the first instar being the most sensitive. Lethal concentrations for D. fovealis 1st instar larvae were 3.4 × 105 and 1.7 × 107 conidia mL−1 with Bea111 and Isa340, respectively. Isa340 performed better than Bea111 for controlling pupae. Scanning electron microscopy revealed the adhesion and penetration structures of both fungi in the 2nd instar infected larvae 6 h after inoculation, while fungal extrusion occurred between 54 and 94 h after spraying with Bea111 and Isa340, respectively. •Beauveria bassiana (Bea111) and Cordyceps javanica (Isa340) were tested against Duponchelia fovealis.•Exposure to Bea111 and Isa340 resulted in larval and pupal infection and mortality.•Bea111 and Isa340 action against D. fovealis was rapid and effective at 109 conidia mL−1.•Bea111 showed the lowest LC50 and LT50 against D. fovealis larvae.•Fungal extrusion started at, approximately, 4 days after spraying.