Mass production of Coenosia attenuata Stein at low cost is very important for their use as a biological control agent. The present study reports the performance of C. attenuata adults when reared on Drosophila melanogaster Meigen or Bradysia impatiens (Johannsem). Different densities (6, 9, 15, 24 and 36 adults per predator) of D. melanogaster or (6, 12, 24, 36 and 48 adults per predator) of B. impatiens were used at 26 ± 1 °C, 14:10 (L:D) and 70 ± 5% RH. The results concluded that C. attenuata adults had higher fecundity, longer longevity and less wing damage when reared on B. impatiens adults compared to D. melanogaster adults. Additionally, C. attenuata adults demonstrated greater difficulty catching and carrying heavier D. melanogaster adults than lighter B. impatiens adults. In this case, 12 to 24 adults of B. impatiens daily per predator were considered optimal prey density in the mass rearing of adult C. attenuata.

Greenhouse cage trials were conducted to evaluate the biocontrol potential of the predatory tiger fly Coenosia attenuata against the Chinese chive maggot Bradysia odoriphaga infesting Allium tuberosum. To enhance pest suppression, we supplemented the predator with alternative prey (Drosophila melanogaster adults), a banana‑based banker medium, and a coir mulch layer across four treatments over 50 weeks. When C. attenuata was released alone (T1), corrected control efficacy against B. odoriphaga larvae ranged from 56.14% to 59.82%. Notably, peak larval suppression was significantly higher in treatments combining the predator with mulch layer (T2: 94.23%) or with the banker media system (T4: 100%). Against adult stages, T1 achieved 32.68%–69.73% corrected efficacy, whereas T2 and T4 reached peak values of 100% and 97.69%, respectively. Predator application also doubled the dry weight of Chinese chive. However, the concurrent use of banker medium and mulch layer (T3) did not produce synergistic effects. Collectively, these findings demonstrate that banker media system and coir mulch layers are effective auxiliary tools for enhancing C. attenuata‑based biocontrol in protected cultivation systems.