Biological and Biochemical Effects of Olive Mill Wastewater on Ceratitis capitata (Wiedemann) (Diptera: Tephritidae)

The Mediterranean fruit fly (Medfly), Ceratitis capitata (Wiedemann, 1824) (Diptera: Tephritidae), is a highly destructive pest that causes significant damage to agricultural products. This study was conducted to determine the effects of crude Olive Mill Wastewater (OMWW) on the survival, reproduction, total protein content, total phenol/flavonoid content, and DPPH/ABTS antioxidant capacity of the Medfly. In toxicity tests, Medfly eggs were incubated on filter paper soaked with crude OMWW. In the first stage, they were fed OMWW in volumes of 1.0, 1.5, 2.0, and 2.5 mL containing 4 g of artificial diet. Newly emerged adults were sprayed with 4 mL of OMWW daily for five days. All experiments were conducted in a laboratory condition at 24 ± 1°C, 50% relative humidity, and a 16 : 8 (L : D) photoperiod. As a result of the study, the hatching rate of eggs on OMWW-soaked filter paper decreased to 53.88 ± 0.33% compared to 97.41 ± 0.64% in the control group. The larval mortality rate increased with the volume of OMWW, reaching 62.1 ± 2.1% at 2.5 mL OMWW, while the mortality rate in the control group was 5.5 ± 2.1%. The corresponding LC50 and LC90 values were 2.130 and 5.586 mL respectively. The highest volume application, 2.5 mL OMWW, prolonged larval development from 11.6 ± 0.8 days (control) to 24.1 ± 0.9 days and increased the pupal mortality rate of larvae fed with 2.5 mL OMWW to 61.8%. Spraying OMWW on adults caused acute mortality at a rate of 18% within 48 h. OMWW application completely suppressed the number of eggs laid by females (354 ± 82 eggs female–1 day–1 (control)). At a moderate OMWW volume of 1.0–1.5 mL, OMWW increased the total protein content in larvae to 20.7–23.8 mg g–1 and the flavonoid and phenolic content by 20–25%, respectively. However, at the highest addition level of 2.5 mL OMWW, the total protein content decreased to 17.17 ± 1.38 mg g–1. In larvae fed with 2 mL OMWW, the DPPH and ABTS free radical scavenging capacities increased to 88.19 ± 0.36 and 91.97 ± 0.16%, respectively. These findings indicate that crude OMWW causes polyphasic toxicity, developmental delays, and oxidative imbalance in the Medfly. We believe this study will introduce a new approach to pest management research.