A simple pouch‐based system for the low‐cost, on‐farm rearing of Neoseiulus californicus and its field efficacy against Tetranychus urticae

Abstract BACKGROUND The two‐spotted spider mite ( Tetranychus urticae ) is a major pest in protected cropping systems, causing substantial economic losses in high‐value crops, including strawberry and oriental melon. Although biological control using predatory mites, particularly Neoseiulus californicus , is widely used, its large‐scale application remains constrained by high production costs and reliance on centralized industrial rearing systems. We developed a simple, low‐input pouch‐based rearing system for the cost‐effective production of N. californicus that can be readily implemented at the farm level. To optimize rearing conditions, we evaluated the effects of pouch material and substrate composition on the population growth of the factitious prey mite Lepidoglyphus destructor . We then assessed the field performance of self‐produced predatory mites in strawberry and oriental melon systems. RESULTS Among tested treatments, a vinyl–paper (VP) breeding pouch containing a 70% wheat bran substrate supplemented with 10% chick feed resulted in significantly higher prey mite densities, indicating that both microenvironmental regulation and nutrient supplementation are critical for optimal prey production. Under optimized conditions, N. californicus populations increased 12.9‐fold within 2 weeks, reaching densities exceeding 1.0 × 10 4 individuals L −1 . In field trials, periodic releases of on‐farm‐produced predatory mites significantly suppressed Tetranychus urticae populations, achieving control efficacies of 83.1% for strawberry and 94.2% for oriental melon relative to untreated controls. CONCLUSION These results demonstrate that the proposed pouch‐based breeding system provides a practical, low‐cost, scalable alternative to conventional industrial rearing approaches that can enhance the accessibility, responsiveness, and cost‐efficiency of on‐farm biological control in protected cropping systems. © 2026 Society of Chemical Industry.