Influence of Weather Conditions on Contamination of Grain Fodder by Micromycetes in the Northwestern Black Sea Region of Ukraine

The amount of precipitation and its seasonal distribution affect the contamination of grain fodder with micromycetes. The use of grain from different crops as animal feed and in the food industry raises concerns about its quality and adherence to sanitary and medical standards. The aim of this study was to investigate the degree of micromycetes contamination in grain fodder (wheat, corn, barley) in the northwestern Black Sea region, taking into account weather conditions during 2017–2022. Methods. After harvesting, grain samples were taken and inoculated into Petri dishes containing potato dextrose agar to establish the total number of fungi and determine their species composition. The number of fungal spores in 1 g of feed was calculated using the method of serial dilutions. Micromycetes species were identified using classical methods based on cultural and morphological characteristics. Moisture conditions during the period of active vegetation, defined as having average daily temperatures above 10 °C, were assessed using the hydrothermal coefficient (HTC) of the Selyaninov method. The HTC was not calculated for months without active air temperatures above 10 °C. Results. In the northwestern Black Sea region of Ukraine, the moderate and dry period has increased from four to eight months, with an HTC of 0.4–0.8. The period of sufficient moisture (2018, 2021) with an HTC of 1.0–1.5 lasted five months. The amount of precipitation and its seasonal distribution in the northwestern Black Sea region affects the contamination of grain fodder with micromycetes. During the years of severe drought (2017, 2022), wheat grain was primarily contaminated with Aspergillus fungi, while corn and barley were contaminated with Penicillium. In the years of moderate drought (2019, 2020), grain feed was most contaminated with Penicillium fungi, and during the period of sufficient moisture (2018, 2021), it was contaminated with Penicillium and Fusarium fungi. Conclusions. The mycobiota of grain fodder in the northwestern Black Sea region of Ukraine is dependent on natural and climatic conditions. Filamentous fungi were the most commonly found in corn grain. During a period of severe drought, the grain was contaminated with fungi from the genera Penicillium (81%) and Aspergillus (78%). The other four fungal genera found were Fusarium (42%), Alternaria (31%), Mucor (16%), and Rhizopus (5%). In years with adequate moisture, the occurrence of Penicillium and Aspergillus fungi decreased by 17% and 14%, respectively, while the incidence of Fusarium fungi increased by 9%. During the period of sufficient moisture, wheat grain samples were primarily affected by fungi of the genera Penicillium (52%) and Aspergillus (45%). Fungi of the genera Rhizopus, Mucor, and Alternaria were isolated at a frequency ranging from 5% to 10%. In severe drought, barley and corn samples were primarily affected by fungi of the genera Penicillium (51%) and Aspergillus (42%). During the period of sufficient moisture, the frequency of isolation for Alternaria, Mucor, and Rhizopus fungi was 9%, 8%, and 4%, respectively.