In this study, field trials were conducted to assess the effectiveness of various treatments, including Imidacloprid, Bifenthrin (Bifenthrin 10% + Imidacloprid 20%), Acetamiprid, Lambda cyhalothrin, orange oil, and Beauveria bassiana (Blas.), for managing the cotton-melon aphid, Aphis gossypii Glover, in cucumber greenhouses in Egypt during 2024 and 2025. This study also assessed the impact of these treatments on the predatory stages of Chrysoperla carnea (Steph.), specifically its larvae and adults. The results indicated that B. bassiana, orange oil and Imidacloprid were significantly less effective at controlling Ch. carnea populations compared to Bifenthrin (10% + Imidacloprid 20%), Acetamiprid, and Lambda cyhalothrin. In contrast, the combination of Bifenthrin (10% + Imidacloprid 20%), Acetamiprid, and Lambda cyhalothrin resulted in the most significant reduction in A. gossypii populations, achieving mean residual effects of 78.24%, 75.75%, and 73.94% in the 2024 season, and 86.95%, 84.98%, and 83.09% in 2025. In contrast, orange oil and Imidacloprid showed the least effectiveness against A. gossypii, with mean residual effects of 70.76% and 61.20% in 2024, and 68.26% and 60.43% in 2025. Both treatments proved to be safer, resulting in less harm to Ch. carnea, with mean residual effects of 60.07% and 47.14% in 2024, and 53.70% and 35.84% in 2025. Notably, B. bassiana demonstrated effectiveness on days 7 and 10 post-treatment, achieving efficacy rates of 73.28% and 86.59%, as well as 78.13% and 89.51% for both years, respectively. The highest mortality rate recorded for A. gossypii due to B. bassiana was 87.50% seven days after applying a spore concentration of 1 × 10^7 spores/ml. In conclusion, it is recommended to incorporate B. bassiana, orange oil, and Imidacloprid into integrated pest management (IPM) strategies to effectively control A. gossypii in cucumbers, while being mindful of their potential impacts on the vegetable Crop.
