Investigation of the effects of various plant-derived essential oils on the adult Mediterranean fruit fly (Ceratitis capitata Wied.) (Diptera: Tephritidae)

The Mediterranean fruit fly, Ceratitis capitata Wied. (Diptera: Tephritidae), is a quarantine pest with over 300 host plants, causing significant economic losses in fruit orchards across the Mediterranean and Aegean regions. As an alternative to the widely used chemical control methods, essential oils have gained attention as an environmentally friendly, safe, and practical solution. This study aimed to evaluate the behavioral orientation and biological efficacy of essential oils extracted from basil (Ocimum basilicum Linn. (Lamiaceae)), eucalyptus (Eucalyptus spp. (Myrtaceae)), and yarrow (Achillea millefolium L. (Asteraceae)) against C. capitata adults under laboratory conditions. A Y-tube olfactometer and topical application methods were employed to determine their potential use in pest management. The results demonstrated that yarrow essential oil exhibited the highest repellent effect (80.60%) compared to basil (35.05%) and eucalyptus (57.14%) essential oils. Based on the repellency scale, yarrow essential oil was classified as having a "very high repellent effect." When the time-dependent toxic effects of the essential oils were compared, each exhibited a distinct toxicity profile. The survival rates of C. capitata adults treated with topical applications of basil and eucalyptus essential oils decreased with increasing essential oil concentrations. Furthermore, yarrow essential oil completely inhibited the oviposition behavior of C. capitata females at all tested concentrations (0.5%, 2%, and 4%), except at 1%. Regarding concentration-dependent toxicity, a general trend of increased mortality with increasing concentration was observed. The highest mortality rates in C. capitata adults were recorded 48 hours post-treatment at a 4% concentration, with basil essential oil causing 86.7% mortality and eucalyptus 78.9%. Meanwhile, yarrow essential oil induced a 76.9% mortality rate at a 2% concentration after 72 hours. These findings highlight the potential of basil essential oil for its toxic effects and yarrow essential oil for its repellent properties, suggesting their promising use as alternative biopesticides for C. capitata management