SUMMARYThe frequency and incidence of A. flavus and A. niger on barley, maize, soybean, sunflower and wheat grain, the abundance of European corn borer (Ostrinia nubilalis) moths and their interaction depending on weather conditions in the 2008-2012 period were studied. Under the agroecological conditions of Serbia, the species A. niger is more frequent than A. flavus, and concerning the crop species, its frequency is highest in kernels of sunflower, than soybean, maize, barley and wheat. A. flavus was extremely dominant on all plant species in 2012 regarding its frequency: 100% on soybean, 95.3% on maize, 65.2% on barley, 57.1% on sunflower and 45.8% on wheat. Furthermore, the incidence of A. flavus was higher in 2012 than in previous years. The uncommonly high frequency and incidence of A. flavus infestation of maize grain in 2012 were caused by extremely stressful agrometeorological conditions, high temperatures and drought over the period from flowering to waxy maturity of maize. The precipitation factor (Pf = precipitation sum / average monthly temperature) showed that 2012 was extremely arid in June (Pf = 0.57), July (Pf = 1.45), August (Pf = 0.15) and September (Pf = 1.42). European corn borer (ECB) was a second factor causing intensive occurrence of A. flavus on maize grain in 2012. The maximum flight of ECB moths was recorded as early as in July (5,149) and, as a result of this, high damage and numerous injuries were detected at harvest. Those injuries were covered by visible olive-green powdery colonies typical of A. flavus. In the chronology of A. flavus occurrence, these are the first data on its very high frequency and incidence under the agroecological conditions of Serbia. As intensive infections with A. flavus were rare in the past 50 years, the level of aflatoxins in maize grain was low.

Managing N inputs in wheat production systems is an important issue in order to achieve maximum profitable production, and minimum negative environmental impact. The aim of this investigation carried out in dry land farming in the Vojvodina province (Serbia) was to estimate the effects of different N fertilization levels (0, 75, and 150 kg N ha -1 ) on some quantitative traits, rain-use efficiency (RUE), N agronomic efficiency (NAE), and N use efficiency (NUE) in two Serbian winter wheat (Triticum aestivum L.) cultivars 'Pobeda' and 'Renesansa'. 'Pobeda' had higher grain yield (4437 kg . NAE and NUE declined at high N rates. Based on the results of this study, farmers should be advised that the use of large amounts of N increases production costs and reduce the economic benefits. The increase in wheat production is possible by selecting adapted genotypes with improved NUE.

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Due to its divergent chemical composition and good nutritional properties, pollen is not only important as a potential food supplement but also as a good substrate for the development of different microorganisms. Among such microorganisms, toxigenic fungi are extremely dangerous as they can synthesize mycotoxins as a part of their metabolic pathways. Furthermore, favorable conditions that enable the synthesis of mycotoxins (adequate temperature, relative humidity, pH, and aw values) are found frequently during pollen collection and/or production process. Internationally, several different mycotoxins have been identified in pollen samples, with a noted predominance of aflatoxins, ochratoxins, fumonisins, zearalenone, deoxynivalenol, and T-2 toxin. Mycotoxins are, generally speaking, extremely harmful for humans and other mammals. Current EU legislation contains guidelines on the permissible content of this group of compounds, but without information pertaining to the content of mycotoxins in pollen. Currently only aflatoxins have been researched and discussed in the literature in regard to proposed limits. Therefore, the aim of this review is to give information about the presence of different mycotoxins in pollen samples collected all around the world, to propose possible aflatoxin contamination pathways, and to emphasize the importance of a regular mycotoxicological analysis of pollen. Furthermore, a suggestion is made regarding the legal regulation of pollen as a food supplement and the proposed tolerable limits for other mycotoxins.

SUMMARyA total of 41 species of fungi were isolated from seed samples of barley, maize, soybean, and sunflower collected at different locations in Serbia. The majority of detected species occurred on barley (35 of 41 species or 87.8%) comparing to soybean (17 of 41 species or 41.5%), sunflower (16 of 41 species or 39.0%) and maize (15 of 41 species or 36.9%). Species belonging to genera Alternaria, Chaetomium, Epicoccum, Fusarium, Penicillium and Rhizopus were present on seeds of all four plant species. Alternaria species were dominant on soybean, barley and sunflower seeds (85.7%, 84.7% and 76.9%). F. verticillioides and Penicillium spp. were mainly isolated from maize seeds (100 and 92.3% respectively), while other species were isolated up to 38.5% (Chaetomium spp. and Rhizopus spp.). F. graminearum, F. proliferatum, F. poae and F. sporotrichioides were the most common Fusarium species isolated from barley (51.1-93.3%), while on the soybean seeds F. oxysporum (71.4%), F. semitectum (57.1%) and F. sporotrichioides (57.1%) were prevalent. Frequency of Fusarium species on sunflower seeds varied from 7% (F. equiseti, F. graminearum, F. proliferatum and F. subglutinans) to 15.4% (F. verticillioides). Statistically significant negative correlation (r = -0.678*) was determined for the incidence of F. graminearum and Alternaria spp., as well as, Fusarium spp. and Alternaria spp. (r = -0.614*), on barley seeds. The obtained results revealed that seedborne pathogens were present in most seed samples of important cereals and industrial crops grown under different agroecological conditions in Serbia. Some of the identified fungi are potential producers of mycotoxins, thus their presence is important in terms of reduced food safety for humans and animals. Therefore, an early and accurate diagnosis and pathogen surveillance will provide time for the development and the application of disease strategies.