Comparative assessment of bio-agents in protected cucumbers against the two-spotted spider mite

Protected cucumber production Cucumis sativus L. (Cucurbitaceae) faces significant threats from infestations by the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae). Globally, T. urticae has been effectively managed using biological control agents such as predatory mites — Phytoseiulus persimilis Athias-Henriot and Neoseiulus californicus (McGregor) (Acari: Phytoseiidae) — and predatory insects, including Stethorus gilvifrons (Mulsant) (Coleoptera: Coccinellidae), and Orius albidipennis (Reuter) (Hemiptera: Anthocoridae). This study aimed to assess and compare the reduction of T. urticae populations on two cucumber cultivars, Barcoda and Hisham, using these four bio-agents in comparison with the conventional acaricide bifenazate. Results showed that P. persimilis achieved a reduction of up to 96.24% on the Hisham cultivar, while S. gilvifrons provided a similar reduction of 94.89% on Barcoda. In contrast, bifenazate resulted in the lowest reduction rates, ranging from 60.23% to 74.96% across the two cultivars. All bio-agents significantly reduced T. urticae populations compared to untreated control. The other predatory species, O. albidipennis and N. californicus, also exhibited substantial, though slightly lower, levels of control. These findings underscore the potential of bio-agents as effective components of integrated pest management strategies for sustainable cucumber production. Further studies are recommended to optimize predator combinations and release rates.