There has been a rapid, worldwide increase in oilseed rape production that has resulted in enormous intensification of oilseed rape cultivation, leading to tight rotations. This in turn, has caused an accumulation of pests as well as foliar and soil-borne diseases. Recently, clubroot has become one of the biggest concerns of oilseed rape growers. Clubroot is caused by the soil-borne protist Plasmodiophora brassicae Woronin. The pathogen may be present in groundwater, lakes, and irrigation water used in sprinkling systems. It can be easily transmitted from one field to another not only by water, but also by soil particles and dust transmitted by wind and on machinery. The aim of our overall study was to check for P. brassicae infestation of Polish agricultural soils. This paper presents the 2012 results of a study performed along the Polish-Ukrainian border in two provinces: Lublin (Lubelskie Voivodeship) and the Carpathian Foothills (Podkarpackie Voivodeship), in south-east Poland. Monitoring was done in 11 counties, including nine rural and two municipal ones. In total, 40 samples were collected, out of which 36 were collected from fields located in rural areas and four from municipal areas, with two per municipal region. Each sample was collected at 8-10 sites per field, using a soil auger. The biotest to detect the presence of P. brassicae was done under greenhouse conditions using seedlings of the susceptible Brassicas: B. rapa ssp. pekinensis and the Polish variety of oilseed rape B. napus cv. Monolit. Susceptible plants grown in heavily infested soils produced galls on their roots. A county was regarded as free from the pathogen, if none of the bait plants became infected. The pathogen was found in three out of 40 fields monitored (7.5%) in the Carpathian Foothill region. The fields were located in two rural counties. The pathogen was not found in Lublin province, and was also not detected in any of the municipal counties. The detection with a biotest was fully confirmed by PCR-based molecular detection of P. brassicae DNA in soil samples.

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.

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.

The increasing demand for sustainable agricultural practices has led researchers to explore alternative methods for controlling plant diseases and pests. Among these alternatives, essential oils (EOs) derived from various plant species have gained significant attention due to their broad-spectrum antimicrobial properties, which can be utilized in plant protection. Essential oils are volatile compounds that possess strong aromatic characteristics and are found in many medicinal and aromatic plants. They are known for their antifungal, antibacterial, and insecticidal activities, making them viable candidates for eco-friendly pest and disease management strategies. In this research, six essential oils—pine, patchouli, geranium, spruce, coriander, and eucalyptus oil—have been tested in vitro for controlling mycelium growth of Sclerotinia sclerotiorum, Botrytis cinerea, Alternaria brassicicola, and Cylindrosporium concentricum. The study also covers experiments in controlling pollen beetle and cabbage seed weevil (laboratory trials). In greenhouse conditions, the phytotoxicity of EOs to oilseed rape (Brassica napus L.) and the effect of these substances on the control of cornflower (Centaurea cyanus) were also tested. The results obtained indicate a large diversity of different essential oils in terms of their action on pathogens, pests, weeds, and winter rapeseed. Differences in their effectiveness were also found, depending on the applied dose.