Corylus avellana (L.) or European hazelnut is a member of the birch (Betulaceae) family. It has a unique floral biology with bloom occurring in the winter, although fertilization of the ovule, and subsequent nut set, is not complete until in mid-May (Thompson, 1979). In Oregon, nut harvest starts in the fall when the nuts fall from the tree and are picked up with mechanical harvesters.
Total world production of hazelnuts in 2008 was 1,066,823 t and 773,828 t in 2009 with Turkey accounting for ≈70% of the total in both years. Italy produces ≈14%, whereas Oregon accounts for 3% to 5% of annual world production (Food and Agriculture Organization of the United Nations, 2010). Oregon's Willamette Valley produces ≈99% of the U.S. hazelnut crop. Growers in Oregon in 2009 produced ≈37,188 t of hazelnuts on 12,545 ha. In the mid-1980s, EFB, caused by the fungus Anisogramma anomala (Peck) E. Müller, was discovered in Oregon's main hazelnut-producing region. The blight has slowly spread and is now present throughout the entire hazelnut-producing area in Oregon.
Braun, L.C., Gillman, J.H. & Russelle, M.P. 2009 Fertilizer nitrogen timing and uptake efficiency of hybrid hazelnuts in the Upper Midwest, USA HortScience 44 1688 1693
Food and Agriculture Organization of the United Nations 2010 (FAOSTAT) 8 Sept. 2010 <http://faostat.fao.org/site/567/DesktopDefault.aspx?PageID=567#ancor>.
Honglin, C., Mehlenbacher, S.A. & Smith, D.C. 2007 Hazelnut accessions provide new sources of resistance to eastern filbert blight HortScience 42 466 469
Johnson, K.B., Mehlenbacher, S.A., Stone, J.K., Pscheidt, J.W. & Pinkerton, J.N. 1996 Eastern filbert blight of hazelnut: It's becoming a manageable disease Plant Dis. 80 1308 1316
Julian, J., Seavert, C.F. & Olsen, J.L. 2009 An economic evaluation of the impact of Eastern filbert blight resistant hazelnut cultivars in Oregon, USA Acta Hort. 845 725 732
Mehlenbacher, S.A. 2009 Release of ‘Jefferson’ hazelnut (OSU 703.007) and pollinizers ‘Eta and ‘Theta’ Proc. of the Nut Growers Society of Oregon Washington and British Columbia 57 63
Molnar, T.J., Goffreda, J.C. & Funk, C.R. 2010 Survey of Corylus resistance to Anisogramma anomala from different geographic locations HortScience 45 832 836
Olsen, J., Righetti, T.L. & Sanchez, E.I. 2000 Absorption and distribution of isotopically labeled nitrogen in the hazelnut tree following ground and foliar applications Acta Hort. 556 437 444
Thompson, M.M. 1979 Growth and development of the pistillate flower and nut in ‘Barcelona’ filbert J. Amer. Soc. Hort. Sci. 104 427 432
Vidyasagar, R.S., Mehlenbacher, S.A. & Smith, D.C. 2010 Response of hazelnut accessions to greenhouse inoculation with Anisogramma anomala (Peck) E. Müller HortScience 45 1116 1119