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-α-Pinene (15.52), camphene (14.00), and β-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.