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In 1989 Erwinia amylovora was confirmed to be a pathogen of pear and quince in Serbia. Subsequently, apple, firethorn, hawthorn, Mespilus spp., Cotoneaster horisontalis and Cheanomeles spp. were confirmed as hosts of the pathogen. During the summer 2005, fire blight symptoms were observed on Sorbus spp. for the first time in the south-eastern Serbia, near Nis. Disease symptoms included leaf and shoot blight and cankers with purple-brown colouration of necrotic tissue on mature branches. The diseased tissue was macerated and the suspension was streaked on nutrient sucrose agar (NAS) and King's medium B. Typical light grey, levan-positive colonies developed on NAS medium after two day incubation at 25°C. Colonies on King's medium B were white and nonfluorescent. The results of physiological and biochemical tests of the bacterium were as follows: gram negative, oxidative and fermentative metabolism of glucose; oxidase negative, gelatin hydrolysis positive, aesculin hydrolysis negative and acid produced from most carbon sources. In pathogenicity tests, all isolates induced HR in tobacco leaves and necrosis on artificially inoculated pear fruits followed by appearence of bacterial ooze. After inoculation of petioles and shoots of the host plant (Sorbus spp.) initial symptoms were dark green, watersoaked, eliptical spots on inoculated tissues. Leaf and shoot blight resembling the natural infection appeared five to six days after inoculation. The investigated strains reacted positively with antisera specific to E. amylovora in DASI ELISA test. Identity of isolated strains also was confirmed by polymerase chain reaction (PCR). According to the biochemical and physiological characteristics, pathogenicity tests, results of PCR analyses and ELISA test, strains isolated from Sorbus spp. plants were identified as E. amylovora. This is the first report of E. amylovora on Sorbus spp. plants in Serbia.

In 1989 Erwinia amylovora was confirmed to be a pathogen of pear and quince in Serbia. Subsequently, apple, firethorn, hawthorn, Mespilus spp., Cotoneaster horisontalis and Cheanomeles spp. were confirmed as hosts of the pathogen. During the summer 2005, fire blight symptoms were observed on Sorbus spp. for the first time in the south-eastern Serbia, near Nis. Disease symptoms included leaf and shoot blight and cankers with purple-brown colouration of necrotic tissue on mature branches. The diseased tissue was macerated and the suspension was streaked on nutrient sucrose agar (NAS) and King's medium B. Typical light grey, levan-positive colonies developed on NAS medium after two day incubation at 25°C. Colonies on King's medium B were white and nonfluorescent. The results of physiological and biochemical tests of the bacterium were as follows: gram negative, oxidative and fermentative metabolism of glucose; oxidase negative, gelatin hydrolysis positive, aesculin hydrolysis negative and acid produced from most carbon sources. In pathogenicity tests, all isolates induced HR in tobacco leaves and necrosis on artificially inoculated pear fruits followed by appearence of bacterial ooze. After inoculation of petioles and shoots of the host plant (Sorbus spp.) initial symptoms were dark green, watersoaked, eliptical spots on inoculated tissues. Leaf and shoot blight resembling the natural infection appeared five to six days after inoculation. The investigated strains reacted positively with antisera specific to E. amylovora in DASI ELISA test. Identity of isolated strains also was confirmed by polymerase chain reaction (PCR). According to the biochemical and physiological characteristics, pathogenicity tests, results of PCR analyses and ELISA test, strains isolated from Sorbus spp. plants were identified as E. amylovora. This is the first report of E. amylovora on Sorbus spp. plants in Serbia.

A recent trend in expanding raspberry production in Serbia has led to extensive planting of new raspberry fields, especially during the past decade. However, introduction and spread of numerous raspberry pathogens resulted in reduced yield and quality of fresh fruit intended mostly for export. In Serbia, only two bacterial diseases had been previously reported on raspberry and these are reviewed in this paper. Symptoms of Pseudomonas blight, expressed as collapse of floricane laterals, followed by wilting and dieback of entire floricanes were recorded on raspberry plants ('Willamette') in western Serbia in 2002-2004. Isolated bacterial strains were identified as P. syringae. Moreover, in spring 2003, gall symptoms on the roots and crown of young raspberry plants ('Wilamette') were observed in western Serbia and were identified as tumorigenic Agrobacterium radiobacter (biovar 1 Agrobacterium). In addition to identification using differential biochemical and physiological characteristics, the identity of strains was also confirmed by polymerase chain reaction (PCR) using primers complementary to tms2 gene located on Ti plasmid and the strains were classified to biovar 1 on the basis of multiplex PCR with primers complementary to chromosomal gene coding for 23S rRNA. Both of the pathogens recorded in Serbia are polyphagous plant pathogenic bacteria with a broad host range. In addition, their inoculum is widely distributed in the environment close to potential hosts. Tumorigenic Agrobacterium species, both crown and cane gall inducers, seriously threaten raspberry production in all major production areas of this crop. Moreover, prohibition of commercialization of plants with tumors increases economic losses from tumorigenic agrobacteria. The economic impact of P. syringae in Serbian raspberry fields, is yet to be determined.

In order to control the causal agent of spur blight of raspberry (Didymella applanata), the efficacy of five conventional fungicides and two biofungicides was evaluated during 2009 and 2010 in one locality in Serbia where a strong epidemic of the target disease was expected. The following materials were tested: Acanto Plus, applied at 1.0 L/ha (picoxistrobin + ciproconazol, DuPont); Amistar Extra, applied at 1.0 L/ha (azoxystrobin + cyproconazole, Syngenta); Folicur EM 50-WP, applied at 2.5 kg/ha (tolylfluanid + tebuconazole, Bayer CropScience); F-Stop, applied at 10.0 L/ha (Bacillus subtilis, Bio-eko centar); Polyversum, applied at 1.0 kg/ha (Pythium olygandrum, Biopreparaty); Signum (boscalid + pyraclostrobin, BASF); and Switch 62.5-WG, applied at 1.0 kg/ha (fludioxonil + cyprodinil, Syngenta). The trials were arranged as randomized plots (10 m long rows), replicated four times with 90-100 plants/plot. The mean percentage values of disease control were calculated from the assessments made towards the end of the trials, when differentiation between treatments was most obvious. Data were analysed by one-way completely randomized ANOVA, and the comparison of means was performed by using Duncan's test. The infection of raspberry canes in untreated control plots was 2.47 (2009) and 3.82 (2010) (expressed as a class of cane infection). In both years, biofungicides F-Stop (7.98 and 11.16%) and Polyversum (14.19 and 16.94%) exhibited the lowest efficacy among the tested products. Acanto Plus, Amistar Extra, Folicur EM 50-WP, Signum and Switch 62.5-WG were effective against the spur blight pathogen and they significantly reduced the disease severity compared with the untreated plots. Among the tested conventional fungicides, Acanto Plus (81.29 and 87.63%) and Switch 62.5-WG (82.28 and 85.29%) showed the highest efficacy in all trials. There was no statistically significant difference in the efficacies of the tested conventional fungicides.

A collection of 41 Erwinia amylovora strains isolated from 8 plant species at 13 locations in Serbia and one location in Montenegro was tested and their relationship was determined based on carbohydrate metabolism and fatty acid composition. Metabolism of carbon compounds was tested using the Biolog GN MicroPlate system. After 24 h of incubation, the resulting metabolic fingerprints were recorded and compared with the Biolog GN database. Fatty acid composition was analyzed by Microbial Identification System and compared with the data from the MIDI database. Our results showed that all strains tested were identified as E. amylovora, with similarity index (SI) between 0.62 and 0.99, using BIOLOG. Based on fatty acid composition, 39 strains were identified as E. amylovora, with SI between 0.61 and 0.92. More than 14 fatty acids were detected, eight of which were present in all strains with more than 1% of the total named peak area. Based on quantitative and qualitative content of fatty acid composition, the isolates were clustered into three groups: alpha, beta and gamma (Euclidian distance lt = 6). Cluster analysis revealed that groups beta and gamma consists of only strains isolated from north Serbia, whereas all strains isolated from central or south Serbia belong to group alpha.

A collection of 41 Erwinia amylovora strains isolated from 8 plant species at 13 locations in Serbia and one location in Montenegro was tested and their relationship was determined based on carbohydrate metabolism and fatty acid composition. Metabolism of carbon compounds was tested using the Biolog GN MicroPlate system. After 24 h of incubation, the resulting metabolic fingerprints were recorded and compared with the Biolog GN database. Fatty acid composition was analyzed by Microbial Identification System and compared with the data from the MIDI database. Our results showed that all strains tested were identified as E. amylovora, with similarity index (SI) between 0.62 and 0.99, using BIOLOG. Based on fatty acid composition, 39 strains were identified as E. amylovora, with SI between 0.61 and 0.92. More than 14 fatty acids were detected, eight of which were present in all strains with more than 1% of the total named peak area. Based on quantitative and qualitative content of fatty acid composition, the isolates were clustered into three groups: alpha, beta and gamma (Euclidian distance lt = 6). Cluster analysis revealed that groups beta and gamma consists of only strains isolated from north Serbia, whereas all strains isolated from central or south Serbia belong to group alpha.

The efficacy of Starner 20 WP, applied at 0.1% and 0.15% rates (oxolinic acid, Sumitomo), Agri-mycin 17 at 0.1% (streptomycin sulfate, Syngenta), Kasumin at 0.4% (kasugamycin, Hokko Chemical Co.), Cuproxat at 0.05% and 0.1% (copper sulfate, Nufarm) and Funguran OH at 0.05% (copper hydroxide, Spiess Urania) against Erwinia amylovora, the causal agent of fire blight in pears, was evaluated in four orchard experiments following artificial inoculation. All treatments were effective against the fire blight pathogen and significantly reduced disease severity in all experiments, compared to the untreated plots. Of the tested bactericides, Starner 20 WP applied at its higher concentration showed the highest efficacy in all trials (86.5-87.5%). There was no significant difference between the efficacies of Starner 20 WP at lower concentration (83.1-82.1%) and Agrimycin 17 (79.2-78.6%). Kasumin was also effective against E. amylovora, compared to untreated plots, although its efficacy (72.5-73.6%) was significantly lower than that of the other antibiotics. Both copper compounds were less effective (61.3-68.4%) in reducing disease severity than antibiotic treatments.