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Inhibition of Ophiognomonia clavigignenti-juglandacearum by Juglans species bark extracts

Informally Refereed

Abstract

A rapid and reliable screening technique is needed for selecting trees with resistance to butternut canker. In a laboratory assay, reagent grade naphthoquinones and crude bark extracts of Juglans species variously inhibited spore germination and growth of Ophiognomonia clavigignenti-juglandacearum, the causal fungus of butternut canker. The in vitro disc assay revealed that the level of inhibition varied by naphthoquinones and by extracts from different species of Juglans and selections of butternut. Ranking the trees by the level of inhibition approximated their level of resistance observed in past assays based on challenging the trees with the fungus through wounds and their response to natural infection in the field. Butternut is known to produce naphthoquinone compounds with antimicrobial activity. These compounds, if produced at different concentrations, may account for the observed range of inhibition levels in the assay and variation in canker resistance among selections of butternut in the field. This assay may have potential use for selecting butternut with disease resistance for conservation and restoration purposes.

Parent Publication

Keywords

Juglans, plantation culture, nut production

Citation

Ostry, M.E.; Moore, M. 2013. Inhibition of Ophiognomonia clavigignenti-juglandacearum by Juglans species bark extracts. In: Van Sambeek, J.W.; Jackson, Elizabeth A.; Coggeshall, Mark V.; Thomas, Andrew L.; Michler, Charles H. eds. 2013. Managing fine hardwoods after a half century of research: Proceedings of the Seventh Walnut Council Research Symposium; 2011 August 1-3; Madison, WI. Gen. Tech. Rep. NRS-P-115. Newtown Square, PA; U.S. Department of Agriculture, Forest Service, Northern Research Station: 17-27.
https://www.fs.usda.gov/research/treesearch/43792