Physicochemical analysis and comparative toxicity of Juniperus phoenicea L. essential oil against Planococcus citri...

Agricultural pests pose a significant threat to global food security by affecting crop production. Many farm producers rely on synthetic chemical pesticides to protect their crops; however recent advances in the use of plant-based pesticides offer an environmentally friendly solution that protects ecosystems and supports organic farming. Therefore, this study evaluated the insecticidal properties of Juniperus phoenicea L. Essential Oil (JpEO) against two common agricultural pests, Planococcus citri and Planococcus ficus. The chemical composition of JpEO extracted by hydrodistillation from Algerian J. phoenicea was characterized using GC-MS. Bioassays were conducted to evaluate the repellency of JpEO and its ability to induce contact and residual contact toxicity at increasing concentrations against vine mealybug P. ficus and citrus mealybug P. citri. The insecticidal activity of JpEO was evident in both species (p < 0.0001). P. ficus consistently exhibited greater sensitivity than P. citri. Contact application of JpEO against P. ficus and P. citri resulted in LC₅₀-LC₉₀ values of 6.30-25.5 and 2.25-13.0 µL mL^-1, respectively. In contrast, the residual contact application yielded LC₅₀-LC₉₀ values of 6.53-26.4 and 6.38-25.8 µL mL^-1, respectively. These results indicate that the application method influences pest mortality. In the insect repellent bioassay, a significant repellency was consistently observed. The repellent percentage ranged from 17.86% to 92.85% against P. citri, particularly after 4 h of exposure. In contrast, for P. ficus, a 53.57% repellent percentage was observed only at the 20 µL mL^-1 concentration. Considering both its behavioral and lethal effects, JpEO shows promise as a potential biopesticide alternative to synthetic pesticides in integrated pest management (IPM) programs. Nevertheless, further studies are needed to comprehensively evaluate the possible effects and practical applicability of this essential oil.