Potential use of Annona (Annonaceae) by-products to Palpita forficifera management: Lethal and sublethal toxicities and residual effect in olive plants

Abstract

Looking for alternatives for the management of the olive tree moth, Palpita forficifera Munroe (Lepidoptera: Crambidae), this study evaluated the lethal toxicity of three formulations prepared from ethanol extracts from seeds of pre-selected species of Annonaceae (Annona mucosa Jacq., Annona muricata L. and Annona sylvatica A. St.-Hil) compared to a synthetic insecticide based on spinosyn (spinetoram 75 mg L−1, Delegate™ 250 WG). At the concentration of 2,000 mg L−1, the formulation based on A. mucosa extract (major compound = acetogenin rolliniastatin-1) was the most promising treatment, presenting ovicide and larvicide effects comparable or superior to the synthetic insecticide used. In addition to lethal toxicity, P. forficifera third instar larvae fed on olive leaves treated with the formulation based on A. mucosa extract (LC50 = 11.91 mg L−1) showed a significant reduction in larval viability (−52%), larvae weight (−21%), pupal weight after 24 h (−11%) and total female fecundity (−17%) compared to the negative control. In semi-field conditions (greenhouse), the promising results obtained in the laboratory were confirmed, with the formulation of the aqueous emulsion of A. mucosa extract [(a at LC90 previously estimated at 24 h (987.11 mg L−1)], presenting a residual effect (≥80% mortality of third instar larvae) within approximately 7 days. Given the results, the formulation based on the ethanol extract of A. mucosa seeds is a promising alternative for the control of P. forficifera larval populations, especially in organic and/or ecological-based production systems.