Overwintering management of Osmia lignaria 



JESO Volume 139, 2008 



of bees imported into Nova Scotia, the life stage of the shipment should be determined, 

 and when possible, cocoons should be placed immediately into controlled storage facilities 

 at 0°C. Subsequent generations reared in Nova Scotia may be kept outside; ambient 

 temperatures in the province are suitable for winter storage as long as bees are placed in 

 sheltered areas to avoid extreme low temperatures beyond the supercooling capacity. In 

 general, wintering O. lignaria in unheated but sheltered conditions is a viable and affordable 

 alternative to expensive controlled storage facilities for apple producers in Nova Scotia. 

 O. cornifrons also showed high survival under different winter storage conditions, with 

 comparable survival in controlled and ambient outdoor conditions in Iowa, USA (Wilson 

 and Abel 1996). 



Based on one year, emergence of O. lignaria populations wintered under ambient 

 conditions in Nova Scotia corresponds favourably with the flowering period of apple (Fig. 

 7), as 2-3 days are required for the majority of females to mate and establish nests (Bosch 

 and Kemp 2003). Prior to apple flowering, dandelion (Taraxacum sp.) serves as a main 

 food source in Nova Scotia (Sheffield 2006). However, since mating and nest establishment 

 would occur during pre-flowering of the crop, caution must be used with spraying to control 

 pre-flowering pests as death of males and females within the crop system could occur. 

 Predictable emergence and tighter synchrony with crop flowering remains the main benefit 

 of controlled storage (Bosch and Kemp 2003). 



Acknowledgements 



This research was completed as part of the graduate studies of the senior author 

 while at the University of Guelph, Guelph, ON, and at Agriculture and Agri-Food Canada 

 (AAFC), Kentville, NS. Funding for this study was provided in part by Agri-Focus 2000 

 and the Agri futures program (Nova Scotia). Thanks to Dr. Philip F. Torchio for providing 

 the bees used in this study, and Dr. Debra L. Moreau and J. Franklin (AAFC) for their advice 

 and assistance with equipment and software/hardware during these studies. Thanks to the 

 staff of AAFC Kentville and the Nova Scotia Fruit Growers' Association for their continued 

 support, to Dr. Laurence Packer (York University, Toronto, ON) and to two anonymous 

 reviews for their helpful comments. 



References 



Bohart, G. E. 1972. Management of wild bees for the pollination of crops. Annual Review 



of Entomology 17: 287-312. 

 Bosch, J. and W. P. Kemp. 1999. Exceptional cherry production in an orchard pollinated 



with blue orchard bees. Bee World 80: 163-173. 

 Bosch, J. and W. P. Kemp. 2000. Development and emergence of the orchard pollinator 



Osmia lignaria (Hymenoptera: Megachilidae). Environmental Entomology 29: 



8-13. 



Bosch, J. and W. P. Kemp. 2001. How to Manage the Blue Orchard Bee as an Orchard 

 Pollinator. Sustainable Agriculture Network Handbook Series. Book No 5. 



15 



