First Report of Eastern Filbert Blight on Corylus avellana ‘Gasaway’ and ‘VR20-11’ Caused by Anisogramma anomala in New Jersey

Abstract

Eastern filbert blight (EFB) is a serious disease of European hazelnut, Corylus avellana L., which causes economic losses in Oregon (OR) where 99% of the U.S. crop is produced. The causal organism, Anisogramma anomala (Peck) E. Müller, is native east of the Rocky Mountains where it is found in association with C. americana Marshall. While C. americana is tolerant, EFB causes cankering, branch dieback, and death of C. avellana (3). EFB was first discovered in Washington State in the late 1960s (1). Since then, it has spread throughout the Willamette Valley of OR. In OR, ‘Gasaway’, an obsolete pollinizer, shows complete resistance to EFB, conferred by a dominant allele at a single locus (4). ‘Gasaway’ has been widely used in breeding at Oregon State University (OSU) to develop resistant cultivars that are used in most new orchards. In January 2008, cankers containing rows of dark brown elliptical stroma, characteristic of EFB, were first observed on more than 25 trees of ‘Gasaway’ growing at the Rutgers University research farms in Adelphia and North Brunswick, NJ. At that time, cankers were also found on 18 trees of ‘VR20-11’ growing on the research farms. ‘VR20-11,’ an offspring of ‘Gasaway’ that carries the same resistance gene, was released by OSU for use as a pollinizer for ‘Barcelona’, an EFB-susceptible but widely grown cultivar in OR. Additional cankers were observed on the New Jersey trees in January 2009 and 2010. To our knowledge, this is the first report of EFB on either cultivar under field conditions. The cankers are smaller than those on susceptible cultivars. Of 61 cankers on 10 trees of ‘Gasaway’, the average length was 11 cm with a range of 4 to 42 cm. Canker lengths on susceptible trees are typically 20 to 100 cm. The cankers appear otherwise alike with stromata, 2 to 4 × 2 mm, up to 2 mm high; perithecia upright, in the lower part of stroma; asci ellipsoid, 35 to 45 × 9 to 12 μm; and ascospores 8 to 11 × 4 to 5.5 μm, hyaline, smooth, ellipsoid, 2-celled, with the lower cell very short (1 to 1.5 μm long and wide). Genomic DNA was isolated from ascospores excised from cankers of ‘Gasaway’ and ‘VR20-11’. ITS1F and ITS2 primers were used to amplify and sequence the internal transcribed spacer 1 region (ITS1) of the rRNA genes (GenBank Accession Nos. HM565133 and HM565132). BLAST analysis of the 238-bp segments showed 99% homology with a sequence of A. anomala (EU683064). Phylogenetic analysis also confirmed that the two isolates are A. anomala. To test viability, ‘Gasaway’ cankers were excised and ascospore suspensions (1 × 106 spores ml–1) were applied to 15 trees of susceptible ‘Barcelona’ in March 2008 following the protocol of Johnson et al. (2). In December 2009, 12 of 15 inoculated trees expressed EFB. ‘Gasaway’ has shown no signs or symptoms of infection by A. anomala over several decades of exposure in OR, which is believed to have a limited diversity of the fungus due to a single-point introduction. Our findings suggest quarantine efforts must be bolstered to prevent further introductions of A. anomala into the Pacific Northwest to protect the viability of the U.S hazelnut industry. References: (1) A. D. Davison and R. M. Davidson, Jr. Plant Dis. Rep. 57:522, 1973. (2) K. B. Johnson et al. Phytopathology 84:1465, 1994. (3) K. B. Johnson and J. N. Pinkerton. Eastern filbert blight. Page 44 in: Compendium of Nut Crop Diseases in Temperate Zones. B. L. Teviotdale et al., eds. The American Phytopathological Society. St. Paul, MN. 2002. (4) S. A. Mehlenbacher et al. HortScience 26:410, 1991.

Identification and Mapping of DNA Markers Linked to Eastern Filbert Blight Resistance from OSU 408.040 Hazelnut

“…The OSU hazelnut breeding program has used 'Gasaway' resistance extensively in breeding, and most recently released cultivars and pollenizers, and advanced selections in trials carry resistance from 'Gasaway'. However, Molnar et al (2010b) showed that an isolate from Michigan can infect 'Gasaway', prompting greater concern about potential breakdown of resistance and a continued search for new resistance sources. Eventually, we envision the pyramiding of two or more resistance genes in a single cultivar for durable resistance.…”

“…The potential breakdown of single resistance genes is always a concern in disease resistance breeding. Molnar et al (2010aMolnar et al ( , 2010b showed that an isolate from Michigan was able to infect 'Gasaway' and OSU 408.040 in New Jersey. One strategy for durable resistance is the pyramiding of two or more resistance genes in a single cultivar.…”

DNA Markers Linked to Eastern Filbert Blight Resistance from a Hazelnut Selection from the Republic of Georgia

“…EFB is generally more severe in a field nursery in New Jersey than in Oregon. In New Jersey, 'Gasaway' trees showed a few small cankers on small twigs (Molnar et al, 2010b). The cankers have stromata, and the cankers expand slowly.…”

“…Most resistant selections from the breeding program carry 'Gasaway' resistance. In greenhouse inoculation studies with various isolates of A. anomala, Molnar et al (2010aMolnar et al ( , 2010b demonstrated that an isolate from Michigan was able to infect 'Gasaway', emphasizing the importance of using more than one source of resistance in breeding. Greenhouse inoculation studies (Chen et al, 2007;Coyne et al, 1998;Lunde et al, 2000;Sathuvalli et al, 2010) identified several C. avellana selections resistant to EFB.…”

Phytoplasmas associated with declining of hazelnut (Corylus avellana) in Slovenia

“…Alternaria from several distinct species can also cause diseases on hazelnut (Belisario et al 2004). In North America, the main diseases of hazelnut are caused by Anisogramma anomala (Molnar et al 2010), with cankering, branch dieback and tree death seen.…”