Technical Abstract: This book explains how to raise blue orchard bee (Osmia lignaria) populations for orchard pollination. The book starts with an overview of orchard pollination requirements, followed by a detailed account on the natural history of the blue orchard bee. The following chapters describe how to build nesting materials, and how to rear blue orchard bee populations, with emphasis on adequate temperature regimes for development, wintering and incubation. Field management is also covered, including distribution of nesting sites, release methods, timing of bee emergence with bloom, and bee densities needed for optimal pollination. The last chapters explain how to quantify blue orchard bee populations, and how to identify parasites, predators and other mortality factors. Information is provided on parasite control methods and how to enhance population increases in general.