Essential oil from Duguetia lanceolata St.-Hil. (Annonaceae): Suppression of spoilers of stored-grain

Abstract

To search for new compounds with promising grain-protective properties, this study evaluated the chemical composition and insecticidal, antifungal and antiaflatoxigenic activities of essential oil (EO) from the hydrodistillation of Duguetia lanceolata (Annonaceae) leaves on fungi and insects that spoil stored commodities. By combining the chromatographic and spectroscopic analyses, 5 compounds were identified in the EO of D. lanceolata leaves, including the major compounds β-bisabolene (56.2%) and 2,4,5-trimethoxystyrene (19.1%). This EO showed promising lethal effects on adult Sitophilus zeamais (LC50 = 457 mg kg−1) and Zabrotes subfasciatus (LC50 = 442 mg kg−1) using a residual contact bioassay. In addition to lethal effects, the EO strongly reduced the number of adult S. zeamais that emerged from the treated samples (EC50 = 480 mg kg−1), the percentage of damaged grains (EC50 = 543 mg kg−1) and the sample weight loss (EC50 = 543 mg kg−1). For Z. subfasciatus, D. lanceolata EO significantly reduced the number of eggs/sample (EC50 = 118 mg kg−1), the number of emerged insects (F1 progeny; EC50 = 119 mg kg−1) and the percentage of damaged grains (EC50 = 148 mg kg−1). However, the EO led to no significant mortality in adults of either species using fumigation. The EO also inhibited radial growth and aflatoxin B1 production in the CCT7638 Aspergillus flavus isolate (Ascomycota) in a concentration-dependent manner. Thus, the EO of D. lanceolata leaves may be a promising source of compounds with potential grain-protective properties.