First outbreaks of fireblight in Slovenia¹

Abstract

Slovenia was recognized as free from Erwinia amylovora until 2001. A low incidence of the disease was reported in 2001 and 2002 in the north-west uplands of the Gorenjska region. In 2001, only 3 trees in extensive orchards were found positive at one location out of 791 monitoring locations all over the country. In 2002, the same location in Naklo and a second one in a 1-km radius were found positive, whilst 875 other monitoring locations were fireblight-free. Despite strict phytosanitary measures implemented after discovery of the first focus, the bacterium spread in 2003 to the entire Gorenjska region, with further spread towards eastern and southern Slovenia. The NPPO registered 184 new foci by the end of the season in Gorenjska. Twenty-three foci are scattered in other regions. Phytosanitary measures were applied in every focus. Spread of the bacterium was probably enabled by favourable weather conditions, the presence of the inoculum and intensive bee-hive movement, resulting in flower infections. Since eradication has not been successful, it is concluded that E. amylovora is now present at low prevalence in Slovenia.

Phylogeography and population structure of the biologically invasive phytopathogen Erwinia amylovora inferred using minisatellites

“…Geographic distance was handled untransformed, as well as log and ln transformed to cover all possibilities. Isolates from Slovenia include isolates from: (i) the first findings of fire blight in 2001 and 2002 in Gorenjska region (Knapic et al ., ), (ii) isolates from two extensive outbreaks in 2003 and 2007 and (iii) isolates from intervening years up to 2009 when conditions were not very conducive for fire blight symptom development and disease occurred sporadically. Our collection of Swiss isolates includes isolates from the years 2002–2009.…”

The status of Erwinia amylovora in the former Yugoslav Republics over the past two decades

“…All seedlings from the nurseries were eradicated (although no visible symptoms were observed at the time of destruction), as well as the infected species and cultivars in orchards and gardens (only plants with symptoms and plants in their vicinity within a radius of 10 m) (Knapic et al, 2004).…”

“…A total of 184 foci were registered in the Gorenjska region, and 23 in other regions. During the survey, 195 infected plants were confirmed by testing: Malus (50%), Pyrus communis (21%), Cydonia 15%, Cotoneaster 10%, Pyrocantha (2%), Crategus (1%) and Chaenomeles (1%) (Knapic et al, 2004).…”

“…Detail data on the economic loss caused by FB in Slovenia in 2003 were presented by Knapic et al (2004). Damage was estimated at 161,300 EUR in the nurseries, at 140,400 EUR in intensive orchards, and 174,500 EUR in extensive orchards and gardens.…”

“…In 2002, E. amylovora was found again at the same site (Naklo) and within a 1 km radius during a systematic survey. Therefore, two locations were found positive in 2002, while the remaining 875 monitored locations were fireblight-free (Knapic et al, 2004;Demšar et al, 2004).…”