The maize weevil, Sitophilus zeamais, is one of the main primary pests of stored grains in the world. Synthetic insecticides are the main means of controlling this pest, but environmental and health issues have been associated with their use. Therefore, natural insecticides have been sought to control pests like this. The objective of this work was to evaluate the insecticidal activity of fixed oil from S. coronata seeds (FOSc) against S. zeamais through ingestion and contact toxicity tests, influence on population growth rate and assessment of residual effect. The main compounds of FOSc were lauric acid (59.88%), myristic acid (13.13%) and capric acid (9.61%). FOSc presented ingestion toxicity with lethal concentrations for 50% (LC50) and 90% (LC90) of insects of 2.58 μL/g and 8.15 μL/g, respectively. The oil was able to inhibit in vitro α-amylase activity from gut extract. In the contact toxicity, LC50 and LC90 were 2.99 μL/g and 6.21 μL/g, respectively. Treating the grains with oil reduced the emergence of insects, reducing the population growth rate. However, FOSc showed low residual effect against the insect under study, being active only for 24 h after its application. In conclusion, S. coronata fixed oil can be used as an alternative to synthetic insecticides to control S. zeamais through ingestion and contact pathways.

中文翻译：

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Syagrus coronata 的种子油具有接触毒性，可减少 Sitophilus zeamais（鞘翅目：Curculionidae）的种群增长


玉米象鼻虫 Sitophilus zeamais 是世界上储存谷物的主要主要害虫之一。合成杀虫剂是控制这种害虫的主要手段，但其使用与环境和健康问题有关。因此，人们一直在寻求天然杀虫剂来控制这样的害虫。这项工作的目的是通过摄入和接触毒性测试评估 S. coronata 种子 （FOSc） 固定油对 S. zeamais 的杀虫活性、对种群增长率的影响和残留效应的评估。FOSc 的主要化合物为月桂酸 （59.88%） 、肉豆蔻酸 （13.13%） 和癸酸 （9.61%）。FOSc 对 50% （LC50） 和 90% （LC90） 昆虫的致死浓度分别为 2.58 μL/g 和 8.15 μL/g。该油能够抑制肠道提取物中的体外 α-淀粉酶活性。在接触毒性中，LC50 和 LC90 分别为 2.99 μL/g 和 6.21 μL/g。用油处理谷物减少了昆虫的出现，降低了种群增长率。然而，FOSc 对研究中的昆虫显示出低残留效应，在施用后仅 24 小时具有活性。总之，S. coronata 固定油可用作合成杀虫剂的替代品，通过摄入和接触途径控制 S. zeamais。