Tropical Plant Extracts as Sources of Grain-Protectant Compounds Against Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae)

Abstract

The toxicity of organic plant extracts to Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) was assessed for three tropical plant species: branches, leaves, and seeds of Annona montana (Annonaceae), branches of Aristolochia paulistana (Aristolochiaceae), and leaves and branches of Casearia sylvestris (Salicaceae). The screening assay resulted that the extracts of A. montana seeds obtained with hexane (LC50 = 534.75 mg kg(-1) and LT50 = 6.10 days) and with dichloromethane (LC50 = 424.67 mg kg(-1) and LT50 = 5.03 days) were the most promising treatments, followed by the extract prepared from A. montana leaves with hexane (LC50 = 837.70 mg kg(-1) and LT50 = 4.90 days). Moreover, extracts (at 1,500 mg kg(-1)) prepared from C. sylvestris branches with dichloromethane and A. paulistana with hexane caused significant mortality (37% and 41.5%, respectively) beyond sublethal effects on S. zeamais. Therefore, based on the biological assays, extraction yield, and evaluation of the chromatographic profile of the crude extracts by TLC, the hexane extract of A. montana seeds was selected and fractioned using liquid-liquid partitioning. The hydroalcoholic fraction caused mortality of 55.5%, significantly superior to dichloromethane fraction, which caused 35.5% of mortality. Chemical analyses ((1)H NMR, HPLC, and TLC) were performed, and the results showed the presence of alkaloids and acetogenins in both active fractions, which have been associated with bioactivity. Therefore, extracts prepared from A. montana seeds (especially) is an interesting source of new compounds with promising grain-protectant properties.

Plant‐Derived Substances Used Against Beetles–Pests of Stored Crops and Food–and Their Mode of Action: A Review

“…A similar effect of 100% mortality was also found in a case involving the hermetic method combined with the toxicity of garlic emulsion usage against T. castaneum and R. dominica (Jahromi, Asgar Pourmirza, & Hasan Safaralizadeh, ). An increased insecticidal effect of this combined method (vacuum storage in combination with a foliage powder of Peumus boldus and lime) against S. zeamais was also reported by (Ribeiro et al., ).…”

Efeito inseticida sistêmico de nanoformulações à base de nim sobre Bemisia tabaci (Hemiptera: Aleyrodidae) biótipo B em tomateiro

“…Muitas investigações têm sido conduzidas visando detectar novas fontes de bioinseticidas para controle de pragas em plantas cultivadas e em produtos armazenados (Amoabeng et al, 2013;Ribeiro et al, 2013Ribeiro et al, , 2014. No entanto, apesar da crescente demanda por produtos mais seletivos e seguros (Isman et al, 2011), poucas formulações têm sido desenvolvidas e disponibilizadas no mercado mundial (Isman & Greineisen, 2014).…”

Bioactivity of Piper extracts on Tuta absoluta (Lepidoptera: Gelechiidae) in tomato

“…medium (6.10%). Although the yield of the leaf extracts can be considered high using ethanol (bipolar solvent), further studies are required to optimize the extraction method of the promising extracts, taking into account the economic aspect of the process and its adequacy to the concepts of environmental sustainability and green chemistry (Ribeiro et al, 2014).…”