Piper spp. essential oils in chitosan-sodium alginate nanocapsules: a sustainable control tool of Drosophila suzukii

Resumo

Nanocapsules (NCs) containing essential oils (EOs) with oppositely charged biopolymers have gained recognition in integrated pest management programs. In this study, we developed NCs containing EOs from Piper aduncum, Piper gaudichaudianum, and Piper marginatum using the Layer-by-Layer (LbL) method, with alternating layers of chitosan (LbL1) and sodium alginate (LbL2). These nanocapsules were designed to manage Drosophila suzukii, a globally significant pest of fruits with thin exocarps and stone fruits. For the three tested EOs, the nanosystems achieved maximum incorporation efficiency ranging from 59.4% to 50.3% in LbL1 and 42.1% to 39.4% in LbL2, with average apparent diameters of 176 nm in LbL1 and 173 nm in LbL2. We found that crude EO of P. marginatum and EO of P. marginatum-LbL2 via ingestion and topical application were promising, killing 90% of exposed D. suzukii adults. These nanosystems also exhibited ovicidal and oviposition deterrent effects on D. suzukii females, rendering 100% of the eggs nonviable and reducing oviposition by up to 85%. We highlight the potential of chitosan-sodium alginate nanocapsules carrying EOs as promising alternatives to synthetic insecticides or even crude EOs with high volatility, water immiscibility, and rapid degradation.