Atividades inseticida e repelente de produtos naturais sobre Ulomoides (=Palembus) dermestoides

Abstract

The beetle Ulomoides (=Palembus) dermestoides is an agricultural pest that compromises stored grains. This study aimed to evaluate the repellent and insecticidal effects of fourteen natural products, commonly found in plant extracts and essential oils. The insecticidal effect was analyzed in a no-choice scenario, while the repellent effect was studied in a choice-based environment. Peanuts treated with the natural products were used as test material, with a control group, free of these substances, established for comparison. It was observed that the most lethal substances did not necessarily coincide with those having the highest repellent effect. In decreasing order of toxicity, the top three positions were occupied by methyl salicylate, salicylaldehyde, and trans-cinnamaldehyde, followed by carvacrol, eugenol, guaiacol, 4-allylanisole, panisaldehyde, trans-anethole, caryophyllene, vanillin, thymol, 4- methoxyacetophenone, and limonene. Regarding repellency, the most effective compounds were eugenol and carvacrol, while caryophyllene, trans-cinnamaldehyde, 4-methoxyacetophenone, and p-anisaldehyde showed moderate effects. The other natural products tested did not demonstrate strong repellent capacity. Based on the results, it can be concluded that the repellent and insecticidal properties are biologically independent. The order of repellent activity suggests that the mechanism of action is not directly influenced by the volatility of the substance, as highly volatile compounds, such as limonene, exhibited low effectiveness under the experimental conditions.