Insecticidal Activity of Cymbopogon citratus and Melaleuca leucadendra Essential Oils and Their Joint Actions Against Spodoptera frugiperda

<p>A high population of <em>Spodoptera frugiperda</em> larvae reduces corn crop productivity. One alternative insect pest control method is the use of mixed essential oils. This research aims to evaluate the insecticidal and antifeedant activity of lemongrass (<em>Cymbopogon citratus</em>) and melaleuca (<em>Melaleuca leucadendra</em>) essential oils against <em>S. frugiperda</em> larvae, as well as their combined effect. The essential oils were produced using a steam distillation method. The insecticidal activities were assayed using feeding method. The levels of essential oil concentration tested and controlled were repeated five times. The concentration-mortality relationship was analyzed using probit. Antifeedant activity tested by choice and no-choice at sub-lethal concentrations equivalent to LC<sub>10</sub>,LC<sub>25</sub>, and LC<sub>50</sub>. The test results showed that insecticidal activity of the essential oils of <em>C. citratus</em> higher than <em>M leucadendra</em>. Both essential oils showed LC<sub>50</sub> values of 0.9% and 1.1% respectively. Both essential oils also showed antifeedant activity. In the choice test and no-choice test at LC<sub>10</sub>,LC<sub>25</sub>, and LC<sub>50</sub> showed feeding inhibition of 23.7%-56.7%. The mixture of the two essential oils has a strongly synergistic action with an LC<sub>50</sub> of 0.15% and a combination index of 0.15. Further research is needed to evaluate the extract mixture in the field.</p>