Sapyga spp.
Pest description These wasps (8-14 mm) are a common cleptoparasite (larvae steal food provisions of the host). Females lay their eggs in sealed brood cells. Emerging larvae kill the bee larvae and consume the bee's provisions.
Management Night station traps, commercially available for Sapyga pumila, a parasite on Megachilae rotundata, may be modified to accommodate the larger size of sapyga adults parasitizing BOBs.
For more information:
Bosch, J. and W.P. Kemp. 2001. How to Manage the Blue Orchard Bee as an Orchard Pollinator. Sustainable Agricultural Network. National Agricultural Library. Beltsville, MD (http://sare.org/publications/bee/blue_orchard_bee.pdf)
Stanley, C. 2012. Blue Orchard Bee (Osmia lignaria). Utah State University Extension and Utah Plant Pest Diagnostic Laboratory. ENT-162-12, 1-4.