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Use of nitrate non‐utilizing ( nit ) mutants to determine phenological stages at which B otrytis cinerea infects wine grapes causing botrytis bunch rot
Author(s) -
Hill G. N.,
Evans K. J.,
Beresford R. M.
Publication year - 2014
Publication title -
plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.928
H-Index - 85
eISSN - 1365-3059
pISSN - 0032-0862
DOI - 10.1111/ppa.12225
Subject(s) - veraison , botrytis cinerea , biology , phenology , vineyard , wine , ripening , horticulture , botrytis , inoculation , berry , fungicide , wine grape , botany , cultivar , food science
Botrytis bunch rot ( BBR ), caused by B otrytis cinerea , degrades wine grapes during ripening, even though infection can occur as early as flowering. Effective BBR management requires knowledge of whether some stages of fruit development are more important than others in relation to infection and BBR severity at harvest. Bunches of V itis vinifera ‘ S auvignon blanc’ and/or ‘ P inot noir’ were inoculated in two vineyard trials and one glasshouse trial with nitrate non‐utilizing ( nit ) mutant strains at three phenological stages: early flowering, pre‐bunch closure ( PBC ) and veraison. Isolates recovered from symptomless berries at veraison and from bunches with symptoms at harvest were screened to measure the incidence of the nit strains used in the inoculations. It was found that latent infections, which resulted in BBR at harvest, could become established at all three phenological stages and no single stage was associated with greater latent incidence or harvest severity than any other stage. It was concluded that a proportion of BBR at harvest resulted from the expression of latent infections that had accumulated throughout the season. However, the time between infection and BBR symptom expression in near‐ripe grape berries was sufficiently short for polycyclic secondary infection to also contribute to epidemic development.