LAUSR

Simple Summary Sitophilus oryzae is one of the main insects that attack stored products around the world. Effective and environmentally friendly substances for managing storage pests are still being sought. Natural plant substances are tested as an alternative to chemical methods. Therefore, laboratory tests were carried out to check the effect of various concentrations of caraway essential oil and L-carvone on rice weevil. The abundance, emigration and mortality of this species were recorded. The highest repellent effect and the highest mortality of Sitophilus oryzae were caused by 0.1% L-carvone and 0.5% caraway essential oil. Lower concentrations of the tested compounds showed stronger repellant properties than higher concentrations. Abstract The aim of the study was to check the effect of Carum carvi L. essential oil and L-carvone on the emigration, repellence and mortality of Sitophilus oryzae L. In the experiments with caraway essential oil, concentrations of 0.1%, 0.5% and 1% were used, and concentrations of 0.05, 0.1, 0.5 and 1% were used with L-carvone. We assessed whether, in what concentrations and after what exposure time the substances acted on S. oryzae as repellents and/or insecticides. The laboratory tests were carried out at 29 ± 1 °C with 60 ± 5% relative humidity (RH). The deterrence, mortality and abundance of insects were noted after 1, 2, 3, 4, 5, 24 and 48 h. For caraway essential oil and L-carvone, the highest repellency was not shown in the highest concentrations that were used in the tests but in the lower concentrations of 0.5% and 0.1%, respectively. In all used concentrations, caraway essential oil showed repellent effects on S. oryzae. The highest repellency (60–98%) was caused by 0.5% caraway essential oil after 1, 2, 3, 4 and 5 h of research and by 0.1% L-carvone (16–100%). The highest mortality of S. oryzae was caused by 0.5% caraway essential oil and 1% L-carvone. L-carvone at a concentration of 0.05% did not cause mortality in S. oryzae. In conclusion, the greatest repellent effects on S. oryzae were caused by lower doses of caraway essential oil and L-carvone. These compounds do not show the normal relationship described in the previous literature on warehouse pests, in which the repellency increased with increasing concentrations of the tested plant material.