Overwintering Stages of Pseudosclerotia Development for Monilinia vaccinii-corymbosi, Causal Agent of Mummy Berry Disease on Highbush Blueberry in North America

Abstract

Mummy berry, caused by Monilinia vaccinii-corymbosi, is an economically important disease of blueberries throughout North America. Pseudosclerotia develop apothecia and produce primary inoculum in coordination with floral bud break. Terminology for M. vaccinii-corymbosi pseudosclerotial overwintering stages is inconsistent throughout the literature, and the progression from development to sporulation has never been cohesively and sequentially outlined. A developmental classification scheme was derived from existing terminology and observations of naturally-conditioned pseudosclerotia over a two-year period in Corvallis, OR. The proposed terminology for pseudosclerotial overwintering stages include maturation, dormancy, germination, emergence, differentiation, and carpogenic germination. The standardization of these terms will allow researchers to better communicate regarding this pathogen. Accepted for publication 19 July 2016. Published 15 August 2016.