First Report of the Quarantine Brown Rot Pathogen Monilinia fructicola on Imported Stone Fruits in Switzerland

Abstract

Monilinia fructicola, causal agent of fruit brown rot, is a quarantine pathogen in Europe (1). It presents a significant threat because of its aggressivity on flowers, shoots, and wood at low temperatures and propensity for sexual reproduction that increases potential for evolutionarily adaptation to new environments, hosts, and fungicides. It is common in North America, Japan, Australia, and South America. It occurs in orchards in France, has been detected but eradicated from Austria and Spain, and has been found on imported peach in Hungary (1,2). In Switzerland, we recently detected M. fructicola in supermarkets on imported fruit with brown rot symptoms similar to those caused by endemic M. fructigena and M. laxa. Preliminary identification was based on distinctive colony and conidial morphology on potato dextrose agar of fruit isolates. Specific identification was determined by polymerase chain reaction (PCR) (3) and sequencing the internal transcribed spacer (ITS) region. Koch's postulates were fulfilled by reproducing brown rot on healthy inoculated fruit. Surveys of imported fruit in markets (n = 42) using PCR revealed M. fructicola on all imported apricot and nectarine from the United States and France, but none on apricot, peach, plum, and cherry from Spain, France, Italy, or Turkey. Field surveys of apricot, peach, plum, prune, nectarine, and cherry orchards in 13 Swiss cantons were all negative (n = 71 in 2003 and 164 in 2005). This report demonstrates that imported fruit is a weak link in quarantine efforts and poses a potential threat. Transmission to local trees via highly dispersible, profuse spores from recycled packaging and disposal sites for discarded fruit has thus far not occurred but the risk deserves attention. Revised regulations for fruit treatment at points of entry and/or scrutiny of origin orchards may be warranted. References: (1) OEPP/EPPO. List of A2 pests regulated as quarantine pests in the EPPO region. Version 2005-09. Online publication with distribution map at http://www.eppo.org , 2005. (2) M. Petróczy and L. Palkovics. Plant Dis. 90:375, 2006. (3) K. J. D. Hughes et al. EPPO Bull. 30:507, 2000.

Frequency of brown rot fungi on blossoms and fruit in stone fruit orchards in Greece

“…It occurs mainly in America, Australia, China and Japan, and is listed as a quarantine pathogen for EU countries (EPPO, ). However, several recent reports have confirmed the presence of M. fructicola in southern and central European countries (Bosshard et al ., ; Petrόczy & Palkovics, ; Duchoslavova et al ., ; De Cal et al ., ; Pellegrino et al ., ). Monilinia fructigena (anamorph Monilia fructigena ) causes mainly fruit rots in pome fruits such as apple or pear and yield losses due to infections of stone fruits are considered to be less important (Byrde & Willetts, ).…”

Effect of temperature and water activity on in vitro germination of Monilinia spp.

“…In the European Mediterranean areas, brown rot of stone fruit is caused by the fungi M. laxa and M. fructigena (De Cal and Melgarejo 1999). In contrast, M. fructicola causes brown rot in India, Japan, Republic of Korea, Oceania and many areas of North and South America and is included in the A2 list of quarantine organisms for Europe [organisms present in the European and Mediterranean organization for plant protection region (EPPO), but contained, under official control] (Bosshard et al. 2006).…”

First report on Monilinia fructicola in the Slovak Republic

“…M. fructicola (G. Winter) Honey has been restricted to Australia, South Africa, North and South America until now and is the European quarantine listed organism (Anonymous 1992). However, it has recently been introduced into Europe, first identified in France (Anonymous 2002a), consequently in Austria (Anonymous 2002b) and is further spreading into other countries where it was identified on both imported and domestic fruits (Bosshard et al 2006;Petroczy & Palkovics 2006;Duchoslavová et al 2007). Due to the economic impact of all species and spreading of the non-European one, the national survey of M. fructicola is conducted on the basis of a European directive.…”