Resistance of olive cultivars to Botryosphaeria dothidea, causal agent of olive fruit rot in Montenegro Jelena Latinovi  c a, * , Angelo Mazzaglia b , Nedeljko Latinovi  c a , Mirko Ivanovi  c c , Mark L. Gleason d a University of Montenegro, Biotechnical Faculty, Department of Plant Protection, Podgorica 81000, Montenegro b University of Tuscia, Faculty of Agriculture, Viterbo, Italy c University of Belgrade, Faculty of Agriculture, Belgrade, Serbia d Iowa State University, Department of Plant Pathology and Microbiology, Ames, IA, USA article info Article history: Received 19 September 2012 Received in revised form 30 January 2013 Accepted 7 February 2013 Keywords: Olive fruit rot Botryosphaeria dothidea Morphological features Phylogenetic analysis Olive cultivar resistance abstract Fruit rot has caused severe damage in olive orchards in Montenegro in recent years. Symptoms of the disease in commercial orchards include necrotic, depressed and clearly delimited spots on fruit. Identity of fungal isolates from infected fruit was confirmed by morphological and molecular evidence as Botryosphaeria dothidea. Pathogenicity was confirmed by fulfillment of Koch’s postulates. Seventeen olive cultivars were assessed for susceptibility to the causal agent. Two native cultivars, Crnjaka and Gloginja, were highly resistant, whereas the most widely grown domestic variety,  Zutica, was susceptible. Intro- duced cultivars Pendolino and Cassanesse were highly resistant and Giarraffa and Ascolana tenera were the most susceptible olive cultivars. This report is the first comparison of cultivar resistance to olive fruit rot in the Balkan region, and the first assessment of resistance in olive cultivars indigenous to this region. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction Olive is a key fruit crop in Montenegro, a nation on the Adriatic Sea that gained its independence in 2006. Montenegrin olive or- chards cover 3200 ha, comprising one-third of the total area in the country that is under fruit cultivation. Autochthonous cultivars are grown both for oil production and for table use, but cv.  Zutica predominates, comprising more than 95% of the trees. Olive fruit rot was recorded during surveys in Montenegro in 1954 and 1986, when the pathogen was identified as Sphaeropsis dalmatica (Thüm) Gigante (Miju skovi c, 2002). Although fruit rot did not cause significant damage prior to 2000, during the last decade it has become widespread and now is one of the most economically important olive diseases in Montenegro. Symptoms of fruit rot include rounded, necrotic, depressed spots in fruit tissue, with clearly delimited edges. As the disease progresses the necrotic spots expand, eventually encompassing entire fruit. Under disease-favorable conditions, black pycnidia appear on the epidermis, exuding conidia in orange-colored drops. Physical damage from stings by the olive fly(Bactrocera oleae) is readily invaded by the pathogen, promoting disease development. There- fore, one of the most important measures for disease management is control of the olive fly by insecticide sprays, sometimes in combi- nation with copper-containing fungicides. However, this strategy poses significant economic and logistical barriers for small-scale commercial growers, who often lack sprayers that can adequately protect large trees in mature olive groves. As an alternative or sup- plementary management tactic, growing cultivars that are resistant to fruit rot would be more practical for small-scale growers, and would also harmonize well with efforts recently made in Mon- tenegrin agriculture to utilize principles of integrated pest man- agement (Montenegro’s Agriculture and European Union, 2006). The taxonomic status of the olive fruit rot fungus has changed many times. It was first described in 1883 by Thümen as Phyllosticta dalmatica Thüm. on olive fruit from Dalmatia, Croatia (Zachos and Tzavella-Klonari, 1979). Later, it underwent sequential reclassifi- cation to Phoma dalmatica (Thüm) Sacc. (Saccardo, 1884), Macro- phoma dalmatica (Thüm) Berl. et Vogl. (Zachos and Tzavella- Klonari, 1979), Sphaeropsis dalmatica (Thüm) Gigante (Gigante, 1934) and Camarosporium dalmaticum (Thüm) Zachos & Tzav.- Klon. (Zachos and Tzavella-Klonari, 1979). Recent work by Phillips et al. (2005) combined genetic and morphological evidence to * Corresponding author. Tel.: þ382 67 257 172; fax: þ382 20 268 716. E-mail addresses: jelenalatinovic@yahoo.com, jelenalat@ac.me (J. Latinovi c). Contents lists available at SciVerse ScienceDirect Crop Protection journal homepage: www.elsevier.com/locate/cropro 0261-2194/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.cropro.2013.02.004 Crop Protection 48 (2013) 35e40