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Seed health testing aims to ensure a healthy crop and to prevent the spread of plant diseases. The need to study and apply both essential oils and plant extracts against seed diseases is growing and becoming more important. Coriander (Coriandrum sativum L.) is an annual herbaceous, aromatic, spicy and medicinal plant from the Apiaceae family, known for its seeds with a characteristic and pleasant odour. In human medicine, coriander is a part of various medicines for the treatment of digestive organs. Phytopathogenic fungi and bacteria are the most common and significant causes of coriander seed disease. The aim of this study was to assess coriander seed health and investigate the possibility of seed disinfection using peppermint (Mentha x piperita) essential oil. The health of the seeds was examined by the filter paper laboratory standard method. Different concentrations (1, 2, 5 and 10%) of peppermint essential oil were used for seed disinfection. The composition of the essential oil was determined by gas chromatographic analysis. The results of seed health analysis showed the presence of a fungus after seven days of incubation in a humid chamber at room temperature. The fungus was identified as Alternaria sp. (sect. Alternaria) based on the symptoms and macroscopic and microscopic features of the fungus (on seed and potato dextrose agar). Immersion treatment of infected seed in peppermint essential oil reduced the presence of Alternaria sp. on coriander seeds. The highest disease inhibition, 69,33%, namely 58,93% without the influence of the emulsifier, was shown by oil solution of 5%. Stagnation in inhibition was observed with a further increase in oil concentration. The results of this study show the possibility of disinfecting coriander seeds with peppermint essential oil to reduce infection with Alternaria sp.

Five essential oils isolated from plants originating from Serbia and ten combinations of the selected essential oils were assayed to test their inhibitory and fungicidal activity against Trchoderma aggressivum f. europaeum Samuels & W. Gams using two distinctive methods: microdilution and fumigant macrodilution methods. The strongest activity was demonstrated by spearmint (Mentha spicata L.) and thyme (Thymus serpyllum L.) oils at the minimum inhibitory concentration (MIC) of 6.25 µl ml-1 using microdilution, and 0.16 µl ml-1 of air using fumigant macrodilution method. The antifungal activity of basil (Ocimum basilicum L.) and peppermint (Mentha piperita L.) was medium, while the oil extracted from St. John's wort (Hypericum perforatum L.) exhibited the lowest activity. None of the selected essential oils exhibited fungicidal effect at minimal fungicidal concentrations (MFC) of over 25 µl ml-1 or 0.32 µl ml-1of air, using microand macrodilution, respectively. When microdilution was used, the strongest antifungal activity was demonstrated by two oil combinations: spearmint-thyme and spearmint-peppermint, having MIC and MFC values of 3.75 µl ml-1. The lowest activity was demonstrated by the basil-St. John's wort essential oil combination, at 30 µl ml-1 MIC, and MFC exceeding 30 µl ml-1. The obtained results indicate possible synergistic effects of essential oils and their components.

Soil-borne fungi belonging to the genus Rhizoctonia are considered to be among the most destructive sugar beet pathogens. Although multinucleate R. solani AG-2-2 is frequently detected as the main causal agent of root rot of sugar beet worldwide, several binucleate (AG-A, AG-E and AG-K) and multinucleate Rhizoctonia (R. solani AG-4, AG-5 and AG-8) have also been included in the disease complex. Due to their soil-borne nature and wide host range, the management of Rhizoctonia root rot of sugar beet is highly demanding. Identification of Rhizoctonia AG associated with root rot of sugar beet is the essential first step in determining a successful disease management strategy. In this paper we report a highly specific and sensitive real-time PCR protocol for detection of R. solani AG-2-2 which showed a high level of specificity after testing against 10 different anastomosis groups and subgroups, including AG-2-1 as the most closely related. Moreover, a similar conventional PCR assay showed the same specificity but proved to be at least a 100 times less sensitive. Future research will include further testing and adaptation of this protocol for direct detection and quantification of R. solani AG-2-2 in different substrates, including plant tissue and soil samples.

Strawberry production is a popular, fast-growing agricultural business in Serbia. Its cultivar selection has been changing fast, following market demands. One of the limiting factors of strawberry production worldwide is black root rot, primarily caused by binucleate Rhizoctonia. Recently, outbreaks of black root rot of strawberry have occurred in Serbia and the estimated disease incidence was up to 30%. Isolates of binucleate Rhizoctonia AG-A were recovered from symptomatic strawberry plants, and characterized on the bases of morphological, molecular and pathogenic features. Despite their uniform morphological characteristics, the isolates demonstrated genetic variability within ITS rDNA, grouping into three different phylogenetic sub-clusters which comprise AG-A isolates originating from Italy, Israel, Japan and the USA. The binucleate Rhizoctonia AG-A from Serbia exhibited uniform virulence on strawberry after inoculation of daughter plants and detached leaf petioles, as well as on seedlings of bean, carrot and sunflower, while they were non-pathogenic to wheat, maize, tomato, pepper, tobacco, cucumber, lettuce, peas, cabbage, rapeseed and sugar beet.

Antifungal activity of two essential oils, cinnamon (Cinnamomum verum J. Presl) and clove (Syzygium aromaticum (L.) Merrill & Perry), was evaluated against Cladobotryum dendroides (Bull.) W. Gams & Hooz, and Lecanicillium fungicola var. fungicola (Preuss) Hasebrauk, the causal agents of cobweb and dry bubble disease of cultivated mushroom. Inhibitory and fungicidal activity of the selected essential oils was assayed using three methods: microdilution, macrodilution fumigant and macrodilution contact method. Comparing all three methods, clove essential oil showed stronger activity than cinnamon against both fungi, having minimum inhibitory concentration (MIC) at the lowest concentrations tested (1.56, 0.02 and 0.1 µl ml-1, respectively). However, cinnamon oil was more toxic to L. fungicola var. fungicola then to C. dendroides in all three methods. Both oils exhibited stronger antifungal effects when used in the macrodilution fumigant than in contact method. The results showed that both cinnamon and clove essential oils have the potential for further in vivo experiments against L. fungicola var. fungicola and C. dendroides and indicated a possible use of these oils in integrated disease management in mushrooms.

Monilinia spp. are economically important pathogens of pome and stone fruits. Four Monilinia species are present in Serbia - Monilinia fructigena, M. laxa, M. fructicola and Monilia polystroma. As detection and identification of Monilinia species are complex, the aim of this research was to evaluate species-specific primers in PCR in order to standardize fast and reliable molecular methods for differentiation between the four Monilinia species. Isolates of M. fructigena, M. laxa, M. fructicola and M. polystroma from apple fruit and referent isolates from Italy and Japan were used for testing. Specific molecular detection of M. laxa was obtained using ITS1Mlx/ITS4Mlx and Ml-Mfg-F2/Ml-Mfc-R1 primer pairs, and M. fructicola using ITS1Mfcl/ITS4Mfcl and Mfc-F1/Mfc-R1 primer pairs. ITS1Mfgn/ITS4Mfgn and ITS1/Mfg-R2 primer pairs, described as M. fructigena species-specific, amplified M. fructigena and M. polystroma, as well. Specific detection of these two species as well as of all four tested Monilinia species was obtained using the reverse primer MO368-5 with forward primers MO368-8R, Laxa-R2 and MO368-10R in separate or in Multiplex PCR reactions. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III 46008]

Sugar beet root rot has severely occurred in our country recently, especially in localities of Pazova, Pećinci, Ruma, Sremska Mitrovica and Šid. From diseased roots as well as from soil collected from the localities where decay occurred, fungal isolates were obtained by bait plant method. Based on their characteristics, they were identified as multinucleate Rhizoctonia sp. During the year of 2004 in Mitrosrem trial field T-11, where the presence of multinucleate Rhizoctonia sp. was confirmed, an experiment under the coordination of Committee for Acknowledgement and Registration of New Cultivars in our country was conducted in order to determine cultivars' tolerance, i.e. their susceptibility and possibility for growing on infested fields. Six cultivars of sugar beet, Laetitia (as standard) and five new ones were included in the investigation. The trial was conducted in accordance with the established and accepted method (Ministry of Agriculture, Forestry and Water Resources, Republic of Serbia). Susceptibility of investigated cultivars was evaluated according to significant production characteristics root yield, sugar content, corrected sugar content, thick juice Q, molasses sugar, content of K, Na and amino-N, polarized sugar yield and white sugar yield, as it was recommended by the method. Conducted investigations have revealed that tested sugar beet cultivars showed different reactions to natural infection with multinucleate Rhizoctonia sp. Concerning root yield as the most important agricultural characteristic, statistically significantly higher yield was obtained with the cultivar under code mark 5 (61.120 kg/ha) whereas the cultivar marked under code 6 had significantly lower yield comparing to the standard (38.100 kg/ha).

This study was carried out in order to identify the major viruses infecting pumpkins (Cucurbita pepo)grown in Serbia. Leaf samples from virus-infected pumpkin plants were collected in mid-July 2001. Naked-seeded and hulled oil pumpkins, patty pan, zucchini and summer squash from three different locations were included (Table 1). Virus-infected plants showed different symptoms (Table 2 and Figures 1-4). Due to the great variability of the symptoms, the causal viruses could not be fully and precisely determined by visual examination only. The infected samples were tested by the biotest, as well as by two serological methods, ELISA and EBIA. Polyclonal antibodies raised against cucumber mosaic cucumovirus (CMV), zucchini yellow mosaic potyvirus (ZYMV), watermelon mosaic potyvirus 1 (WMV-1), watermelon mosaic potyvirus 2 (WMV-2) and squash mosaic comovirus (SqMV) were used. In each of the 50 collected samples one or two viruses were detected (Tables 3 and 4). The most prevalent viruses infecting pumpkins were ZYMV (62%) and CMV (58%). WMV-2 was extremely rare.

Antigenic properties and serological relationship was investigated in binucleate and multinucleate Rhizoctonia spp. isolates from strawberries soybean, alfalfa and potato plants from Serbia, from Spain, anastomosis group testers and in strawberry roots inoculated with binucleate Rhizoctonia AG A and AG I. Two polyclonal antisera, unabsorbed and cross absorbed, were used in dot-immunobinding assay for these investigations. Antisera were produced against mycelial antigens of two isolates, which belong to different anastomosis groups (AG) of binucleate Rhizoctonia - AG A and AG I. Both unabsorbed antisera reacted positively with all tested Rhizoctonia spp. isolates, and the reaction was absent with control isolates (Pythium sp. Agaricus sp. and Fusarium sp). The results prove a close serological relationship among Rhizoctonia spp. isolates, and diversity between Rhizoctonia spp. and isolates from different taxonomic groups. Also, both unabsorbed antisera reacted with higher intensity with closely related antigens (belonging to the same AG) than with ones from another AG of binucleate Rhizoctonia or R. solani (multinucleate Rhizoctonia). After cross absorption specificity of the antisera was enhanced, especially with the antiserum raised against mycelial proteins of binucleate Rhizoctonia AG I. This antiserum reacted positively only with antigens from the same AG, after cross absorption with antigens from AG A of binucleate Rhizoctonia and from R. solani AG 2-2. It proved to be specific to AG I of binucleate Rhizoctonia, and able to differentiate isolates of this AG from others. In this way the serological homology among isolates of one AG was proven, and also the diversity among isolates which belong to different AGs of binucleate Rhizoctonia as well as isolates of R. solani.

A survey on summer squash open field crops was carried out during 2000 and 2001 in order to identify the major viruses infecting these crops in different localities. Plants showed different types of symptoms: mild mosaic, chlorotic spotting, distinctive mosaic, blistering of leaf lamina leaf yellowing, deformation of leaf lamina, knobbed fruits and stunting of plants. The symptoms were very variable but showed the viral nature of the investigated summer squash diseases. The collected samples were tested by bioassay and by two serological methods ELISA and EBIA using cucumber mosaic cucumovirus (CMV), zucchini yellow mosaic potyvirus (ZYMV), watermelon mosaic potyvirus 2 (WMV-2), zucchini yellow flack potyvirus (ZYFV) watermelon mosaic potyvirus 1 (WMV-1), squash mosaic comovirus (SqMV) and cucurbit aphid-borne yellows polerovirus (CABYV) polyclonal antisera. In all tested samples single or mixed infection with ZYMV, CMV and WMV-2 was detected. The most prevalent virus infecting summer squash was ZYMV. This is the first report of ZYMV, the most destructive virus infecting cucurbits, in Yugoslavia. It was also proven that the identified viruses are transmissible by Aphis gossypii in a non-persistent manner, but possible role of seed in virus transmission was not confirmed.