Annona spp. derivatives: Sublethal effects and behavioral interference on the European pepper moth and an associated predator

Allelochemicals from Annona (Annonaceae) species can be a sustainable tool in the control of the European pepper moth, Duponchelia fovealis, a key pest of strawberry. In this study, we assessed the sublethal (LC25) effects of aqueous emulsions prepared from ethanolic seed extracts (ESA) of Annona mucosa and Annona sylvatica on reproductive parameters of D. fovealis and on its associated predator, Chrysoperla externa larvae. An annonin-based botanical insecticide (Anosom® 1 EC) and a chlorfenapyr-based synthetic insecticide (Pirate®) were used as positive controls. In addition, we evaluated the damages to the excretory and nervous systems of D. fovealis larvae by means of histological assessments. The toxicity of ESA prepared from A. mucosa (LC25) was lower than that of Anosom® 1 EC. Male longevity was inhibited when couples were exposed to Anosom® 1 EC, while males treated with ESA A. sylvatica showed the highest longevity. When males were exposed to ESA A. mucosa, a considerable reduction in the number of eggs was observed. In contrast, the number of eggs increased when males were exposed to Pirate®. No avoidance was observed when larvae were treated with ESA A. mucosa or Anosom® 1 EC, whereas for ESA A. sylvatica or Pirate® larvae were attracted. Concerning C. externa, ESA caused avoidance, but no behavioral interference was observed for Anosom® 1 EC, while attraction occurred for Pirate®. Histological alterations in larvae organs were observed when treated with ESA (LC25) from A. mucosa and A. sylvatica. Our results proved the potential of ESA, even at low concentrations, in the framework of D. fovealis integrated management.