Annona (Annonaceae) by-products derivatives: Toxicity to the European pepper moth and histological assessment

Abstract

Obtaining derivatives with insecticidal properties from abundant plant biomass (waste) represents a good opportunity to transform environmental problems into innovative solutions for pest management programs. In the present study, we evaluated the toxicity of the aqueous emulsions of the ethanolic extract of Annona mucosa and Annona sylvatica (Annonaceae) seeds on the European pepper moth Duponchelia fovealis (Lepidoptera: Crambidae), a major pest of strawberry plants. In addition, we evaluated anti-feeding and developmental inhibitory effects, as well as macro and microscopic damage to the excretory and nervous systems of European pepper moth larvae. In the contact bioassay, the aqueous emulsion of A. mucosa extract provided the fastest action on larvae with LT50 of 6.10 h, followed by chlorfenapyr (Pirate®) (LT50 = 8.2 h) and the aqueous emulsion of the A. sylvatica extract (LT50 = 10.3 h). In contrast, the commercial bioinsecticide based on acetogenins (Anosom® 1 EC) had a higher LT50 (32.8 h). In addition to the lethal effects, the aqueous emulsions tested caused significant phagodeterrence (>90%) and inhibited the development of D. fovealis. Macroscopic observation revealed the presence of edemas as well as the darkening on the surface of the larvae's cuticle. Histological analyses detected alterations. Our results suggest that aqueous emulsions produced from ethanolic extract of A. mucosa and A. sylvatica seeds, a residue in fruit processing industrial complexes (pulp factories), are alternatives for the management of D. fovealis, especially in organic and/or ecological strawberry production systems.