Investigation of Pesticidal and Insecticidal Activity of Essential Oil Extracted from Selected Local Plants (Juniper Procera and Aloe Vera Leaves)

Abstract

This study aimed to investigate the pesticidal and insecticidal activities of essential oils extracted from locally available Juniper procera and Aloe Vera leaves against cochineal and cockroach insects. The essential oils were extracted using Soxhlet extraction. To determine the optimal conditions for maximum essential oil yield, the study evaluated a range of temperatures (70°C 90°C), particle sizes (<0.5mm – 4mm), and extraction times (4hr–6hr). The maximum yield obtained for Juniper procera leaves essential oil was 4.5% under optimal conditions of 80.01°C, 5.82 hours of extraction time, and a particle size of 0.5mm. For Aloe Vera leaves essential oil, the maximum yield was 23.33%, obtained with a particle size of less than 0.5mm, a temperature of 80°C, and an extraction time of 4.5 hours. The pesticidal and insecticidal activities of Juniper procera and Aloe Vera leaves essential oils, as well as their mixture, were investigated against cochineal insects (cactus pests) and cockroaches. The study evaluated the effect of essential oil concentration and exposure time on the mortality of both insect types. For each essential oil and the mixture, the same concentrations were applied to the selected insects, and mortality was observed at 1, 2, and 3 days post application. The results indicated that Juniper procera essential oil exhibited slightly better pesticidal activity against cochineal insects, with lethal concentrations (LC50 and LC90) of 4.52 b mg/ml and 18.06 mg/ml, respectively. The mixture of both essential oils showed intermediate activity (LC50 = 6.52 mg/ml, LC90 = 20.76 mg/ml), while Aloe Vera essential oil demonstrated the least activity against cochineal insects (LC50 = 7.98 mg/ml, LC90 = 22.72 mg/ml). Similarly, Juniper procera essential oil displayed slightly superior insecticidal activity against cockroaches (LC50 = 3.20 mg/ml, LC90 = 9.12 mg/ml), followed by the essential oil mixture (LC50 = 4.31 mg/ml, LC90 = 10.40 mg/ml), and then Aloe vera essential oil (LC50 = 5.08 mg/ml, LC90 = 11.85 mg/ml).