Susceptibility of Duponchelia fovealis Zeller (Lepidoptera: Crambidae) to Soil-Borne Entomopathogenic Fungi

Duponchelia fovealis (Lepidoptera: Crambidae) is an invasive species that has had a large impact on strawberry crops in Brazil. Pesticides have had limited effectiveness and the use of biological control agents to improve its management is the most appropriate approach. The aim of this study was to evaluate the pathogenicity and virulence of entomopathogenic fungi—isolated from soil—against Duponchelia fovealis larvae under laboratory and greenhouse conditions. Pathogenicity screenings were performed for twenty isolates from Beauveria bassiana, Beauveria caledonica, Isaria javanica, Metarhizium anisopliae, and Lecanicillium sp. against third instar larvae of D. fovealis at the concentration of 109 conidia·mL−1. Lethal concentration (LC50) and lethal time (LT50) were determined for the most pathogenic isolates and for one commercial mycoinsecticide. Mortality rates varied from 10 to 89%. The isolates B. bassiana Bea1, Bea110, Bea111 and I. javanica Isa340 were the most pathogenic. The most virulent isolates were B. bassiana Bea111 and I. javanica Isa340 with LC50 values of 2.33 × 106 and 9.69 × 105 conidia·mL−1, respectively. Under greenhouse conditions, the efficacy of LC50 of the isolates I. javanica Isa340 and B. bassiana Bea111 were 45% and 52%, respectively. Our results indicate that these isolates are strong candidates for application in the control of D. fovealis. This study is the first evaluation of soil-borne entomopathogenic fungi against D. fovealis

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

31 Pags.- 2 Tabl.- 6 Figs. The definitive version is available at: https://www.sciencedirect.com/science/journal/02612194Entomopathogenic 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.This work was supported by Coordination for the Improvement of Higher Education Personnel (CAPES) [grant numbers 1726812 and 1771724], and National Council for Scientific and Technological Development (CNPq) [grant number 403266/2013–0].Peer reviewe

Compatibility between Entomopathogenic Fungi and Egg Parasitoids (Trichogrammatidae): A Laboratory Study for Their Combined Use to Control Duponchelia fovealis

The European pepper moth, Duponchelia fovealis (Lepidoptera: Crambidae), is a key pest in strawberry production. Entomopathogenic fungi (EF) and parasitoids of the Trichogrammatidae family are effective biological control agents of this pest with the potential to be used jointly for improved efficacy. This study aims to evaluate the susceptibility of Trichogramma atopovirilia and Trichogramma pretiosum to two Beauveria bassiana strains (B2 and B3) and two commercial bioinsecticides (Bovemax® and Methamax®) by applying them to D. fovealis eggs in pre- and post-parasitism periods. Pre-parasitism application of B2 and B3 did not affect the percentage of D. fovealis eggs parasitized by either Trichogramma species, except in the case of T. atopovirilia when eggs were sprayed with B3 at 1.5 × 105 conidia mL−1 (16.7% less than the control). In contrast, eggs sprayed with 1.5 × 108 conidia mL−1 of the commercial bioinsecticides were not parasitized by any Trichogramma species. Overall, the EF tested reduced the parasitism rate, adult emergence, and longevity of Trichogramma adults by less than 30% in all cases. The adverse effects of the B. bassiana strains and commercial products on the biological traits of both Trichogramma species were minimal, meaning that these agents can be used jointly in D. fovealis control strategies.Publishe

Compatibility between Entomopathogenic Fungi and Egg Parasitoids (Trichogrammatidae): A Laboratory Study for Their Combined Use to Control Duponchelia fovealis

14 Pags.- 2 Tabls- 4 Figs. © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).The European pepper moth, Duponchelia fovealis (Lepidoptera: Crambidae), is a key pest in strawberry production. Entomopathogenic fungi (EF) and parasitoids of the Trichogrammatidae family are effective biological control agents of this pest with the potential to be used jointly for improved efficacy. This study aims to evaluate the susceptibility of Trichogramma atopovirilia and Trichogramma pretiosum to two Beauveria bassiana strains (B2 and B3) and two commercial bioinsecticides (Bovemax® and Methamax®) by applying them to D. fovealis eggs in pre- and post-parasitism periods. Pre-parasitism application of B2 and B3 did not affect the percentage of D. fovealis eggs parasitized by either Trichogramma species, except in the case of T. atopovirilia when eggs were sprayed with B3 at 1.5 × 105 conidia mL−1 (16.7% less than the control). In contrast, eggs sprayed with 1.5 × 108 conidia mL−1 of the commercial bioinsecticides were not parasitized by any Trichogramma species. Overall, the EF tested reduced the parasitism rate, adult emergence, and longevity of Trichogramma adults by less than 30% in all cases. The adverse effects of the B. bassiana strains and commercial products on the biological traits of both Trichogramma species were minimal, meaning that these agents can be used jointly in D. fovealis control strategies.This research was funded by grants from the Coordination for the Improvement of Higher-Level Personnel (CAPES), the National Council for Scientific and Technological Development (CNPq), and the Araucária Foundation for the Support of Scientific and Technological Development (FA). The APC was funded through discount vouchers obtained by José M. Mirás-Avalos for reviewing several MDPI journals.Peer reviewe