No abstract

Fungicides are widely used to reduce Fusarium infections and grain contamination by mycotoxins and increase the yield in cereals, but the efficacy of fungicide treatments in varying climates has not been systematically explored. Field experiments with Estonian spring barley (Hordeum vulgare L.) cv. ‘Maali’ were carried out in three successive years 2012–2014 with strongly varying weather conditions to study the effects of three fungicides, Folicur (active ingredient tebuconazole), Falcon Forte (prothioconazole, tebuconazole, spiroxamine) and Archer Top (fenpropidin, propiconazole), on the yield, incidence of Fusarium spp. and on the contamination of grain with mycotoxins DON, HT-2 and T-2. The fungicides were sprayed once a year at spring barley flowering time. The weather conditions during the three years of study were extremely different. The content of cycotoxin DON, HT2 and T2 was low. The spraying with fungicides had not a clear effect on the barley yield and 1 000 kernel weight, and the study year was primarily the main factor that affected barley yield (p<0.05) and 1 000 kernel weight (p<0.05). The impact of year together with fungicide treatment had a significant effect on the incidence of Fusarium spp. (p<0.05) and on the incidence of mycotoxin DON in barley kernels (p<0.001), but did not have a clear effect on the incidence of mycotoxins HT2 and T2.

For centuries barley has been an important food crop for mankind. It is important to produce crops that are of good quality and safe to human and animal organisms. However, pathogenic fungi in cereals cause health problems both to humans and animals. In Estonia the microbiological quality of cereals has been studied to identify Fusarium species in feed cereals. Still, the relationship between the agro-ecological conditions and the total abundance of moulds and yeasts on grain has been studied little in Estonia. In 2009 and 2010, we carried out field trials in the experimental station of the Estonian Research Institute of Agriculture in North Estonia (59°18′N, 24°39′E) and in the experimental station of Olustvere School of Service and Rural Economics in Central Estonia (58°33′N, 25°34′E). The variants of the experiment were barley in pure crops with added ammonium nitrate 120 kgN ha -1 , barley in pure crops with added ammonium nitrate 60 kgN ha -1 , barley in pure crops with no added ammonium nitrate, and barley-pea mixed crop. After harvesting, the grain was dried to 14% of moisture and grain samples were taken from each trial variant. The abundance of moulds, yeasts, and Fusarium spp. was determined in grain samples using the dilution method. The impact of the levels of nitrogen, location of the trial site, and year (weather conditions) on the abundance of moulds, yeasts, and Fusarium spp. was studied. The common genera of moulds identified were Cladosporium, Acremonium, and Fusarium.