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Impact of Various Essential Oils on the Development of Pathogens of the Fusarium Genus and on Health and Germination Parameters of Winter Wheat and Maize
Currently, researchers are looking for ways to replace synthetic pesticides with substances of natural origin. Essential oils are produced by plants, among other things, to protect against pathogens, which is why there is interest in their use as fungicides. This experiment assessed the composition of essential oils from a commercial source, their impact on the development of mycelium of pathogens of the Fusarium genus, and the possibility of using them as a pre-sowing treatment. Grains of winter wheat (Triticum aestivum L.) and corn (Zea mays L.) were inoculated with a suspension of mycelium and spores of fungi of the Fusarium genus and then soaked in solutions containing oils of sage (Salvia officinalis L.), cypress (Cupressus sempervirens L.), cumin (Cuminum cyminum L.), and thyme (Thymus vulgaris L.). The obtained results indicate that thyme essential oil had the strongest effect on limiting the development of Fusarium pathogens and seedling infection, but at the same time it had an adverse effect on the level of germination and seedling development of the tested plants. The remaining essential oils influenced the mentioned parameters to varying degrees. Selected essential oils can be an alternative to synthetic fungicides, but they must be selected appropriately.
Protection of Oats against Puccinia and Drechslera Fungi in Various Meteorological Conditions
Due to their multi-purpose use and, in many cases, lower requirements and financial outlays for cultivation, oats are an interesting crop. However, fungal diseases may contribute to significant declines in grain yields and quality. The aspects that may potentially influence this matter of fact include weather conditions. The aim of the study was to determine the severity of diseases caused by fungi in oat cultivation during the vegetation season. The next goal was to assess the efficacy of the selected active ingredients (a.i.) of fungicides from the chemical groups of triazoles and strobilurins in selected diseasesâ control under various meteorological conditions. All of the fungicides were applied in the form of a spray treatment to reduce the severity of the diseases in the cultivation of different oat varieties. Husked and naked oat varieties were used. The health status of the oat plants was determined on the basis of a macroscopic evaluation of plants performed in accordance with the proper methodology. Field experiments were carried out under different weather conditions, which varied over the years during which the trials were conducted. Statistically significant differences were found in the reduction in infection for F and F1 leaves with D. avenae and P. coronata in comparison to the control treatment, regardless of the a.i. used. The use of a.i. tebuconazole (250 g/L), a.i. epoxiconazole (125 g/L), a.i. azoxystrobin (250 g/L) and a.i. picoxystrobin (250 g/L) enabled a reduction in the severity of oat helmintosporiosis in all years of the study for all the varieties analyzed. The efficacy was 72.4%, 74.2%, 71.5%, and 73.1%, respectively. Higher efficacy in reducing P. coronata was found in comparison with D. avenae. The obtained research results confirm the satisfactory efficacy of the above-mentioned active substances in reducing the fungi D. avenae and P. coronata.
The Efficacy of Plant Pathogens Control by Complexed Forms of Copper
Copper is a substance that has been used in plant protection for years. Currently, however, more and more attention is being paid to the need to limit the amount of it that ends up in the natural environment. At the same time, it is necessary to partially replace synthetic fungicides with alternative preparations. It is therefore worth looking for forms of copper that will contain a smaller amount of the mentioned ingredient while being highly effective. This experiment assessed the effect of selected preparations on the development of mycelium of pathogens of the Fusarium genus and the germination parameters of winter wheat. The efficacy of copper lignosulfonate and copper heptagluconate in seed treatment was tested, comparing them to copper oxychloride, copper hydroxide, and tebuconazole. The obtained results indicate that the use of copper lignosulfonate and copper heptagluconate allows for the effective limitation of the development of the tested pathogens (mycelium development was inhibited by up to 100%). Most of the preparations had no effect on the energy and germination capacity of winter wheat (only in one combination were the values lower than 90%). The use of preparations containing reduced doses of copper is an effective solution when applied as seed dressings.
Biocontrol of Cercospora leaf spot in sugar beet by a novel Bacillus velezensis KT27 strain: Enhanced antifungal activity and growth promotion in laboratory and field conditions
Diseases in crops are a major contributor to yield reduction and economic losses. Cercospora leaf spot (CLS), caused by Cercospora beticola, is among the most severe diseases affecting sugar beet and other crops. The increasing resistance of C. beticola to conventional chemical fungicides, along with their excessive application, exacerbates environmental pollution. This study investigates the antagonistic activity of a newly isolated strain, Bacillus velezensis KT27, against Cercospora beticola, Rhizoctonia cerealis, and Fusarium oxysporum under laboratory conditions. The bacteriumâs ability to produce lipopeptides (surfactin, iturin, and fengycin) and solubilize phosphorus, potassium, and zinc was also assessed. In vitro assays revealed that B. velezensis KT27 effectively inhibited C. beticola growth (60.2%), though it exhibited lower antagonistic activity against R. cerealis (22.5%) and F. oxysporum (15.5%). The elimination of bacterial biomass by centrifugation and the use of sterile supernatant reduced antifungal activity by more than 3.5-fold for all tested fungi, highlighting the importance of direct bacterial interactions. Notably, the antagonistic effect of B. velezensis KT27 against C. beticola significantly increased when bacterial cultures were supplemented with thermally inactivated fungal biomass of C. beticola especially R. cerealis. Field experiments demonstrated the high efficacy of B. velezensis KT27 biological control agent, particularly when induced by R. cerealis. The level of CLS protection achieved with the bacterial treatment was only 9.1% lower than that obtained using a combination of three chemical fungicides. Additionally, the biocontrol agent positively influenced sugar beet growth, leading to a root yield increase of up to 15.2% compared to the untreated control. These findings highlight the potential of B. velezensis KT27 as an effective and environmentally sustainable biocontrol agent against CLS in sugar beet cultivation.