Efficiency of Schinus molle Essential Oil against Bactericera cockerelli (Hemiptera: Triozidae) and Sitophilus zeamais (Coleoptera: Dryophthoridae)

The present study determines the chemical composition of Schinus molle essential oil and its mortality and repellent effect on Bactericera cockerelli immature stage and Sitophilus zeamais adults. Twenty-four compounds were identified and the most abundant were o-Cymene (29.04), 1R-alpha-Pinene (15.52), camphene (14.00), and beta-myrcene (11.54). On the fifth-instar psyllid nymph, the LC50 and LC90 at 48 h were 442.67 and 864.29 ppm, and for the fourth-instar were 273.41 and 534.67 ppm. The maize-weevil registered an LC50 and LC90 of 343.25 and 986.96 ppm for the fifteenth day. A selection index (Si) of 0.37 with 800 ppm was registered, showing the highest repellent activity, while with the lowest concentration (50 ppm), non-repellent activity was recorded. However, all concentrations above 100 ppm showed repellency against the maize weevil. The study reveals, for the first time, the essential oil's insecticidal effects on the fourth and fifth nymphal stage of the potato/tomato psyllid B. cockerelli and the usefulness of the essential oil as a repellent against adult of S. zeamais. The Si effect on maize weevil was grouped into categories.

Automated summary

The present study identifies the chemical composition of Schinus molle essential oil and investigates its lethality and repellency effects on Bactericera cockerelli nymphs and Sitophilus zeamais adults. The essential oil shows insecticidal effects on the fourth and fifth nymphal stages of B. cockerelli and acts as a strong repellent against S. zeamais at a concentration of 800 ppm.