The study presents the results of research on the influence of a mineral growth stimulant containing titanium (Ti) in the form available to plants, applied to reduce the effects of biotic stresses caused by agrophages, namely fungal pathogens and selected insect pests. The study was conducted in 2014 and 2015 on winter oilseed rape, winter wheat, and maize. The purpose of the study was to determine the influence of the Ti-containing stimulant on the degree of damage caused by major pests occurring in the crops (cabbage seed weevil, cereal leaf beetle, and European corn borer), the degree of infestation with fungal diseases (gray mold, Alternaria disease, eyespot, foot rot, sooty mold, glume blotch, Fusarium head blight, Fusarium stalk rot, maize smut, and brown spot), and yield parameters. The study showed that the stimulant containing Ti successfully reduced the occurrence of pest damage to winter rapeseed and winter wheat plants and the occurrence of diseases in winter rapeseed, winter wheat, and maize crops. Thus, the application of the Ti stimulant resulted in an increased yield of the crops being tested. The main factor explaining this phenomenon is unknown, and it is probably the result of several factors. The study contains the discussion on this phenomenon.

The aim of the research was to determine the influence of acetamiprid and deltamethrin on the mortality and behaviour of honeybees of the same variety, coming from the same source and estimated to be in good condition by a professional beekeeper, but in different years and under different weather conditions. Results of research conducted in field isolators in oilseed rape fields in the years 2012-2018 showed no acetamiprid influence either on the mortality or on the behaviour of honeybees. Deltamethrin activity differed from a lack of influence through causing mortality and a weaker condition of honeybee colonies to the destruction of the colony. This demonstrates the relative safety of acetamiprid to honeybees and the high risk of deltamethrin use. The differences in the bee colonies' reaction to deltamethrin are probably caused by the high acute toxicity of this active ingredient, genetically dependent, variable metabolic capabilities of particular bee colonies, or coexistence of a variety of different stressors-mainly pathogens.

Cabbage seed weevil (Ceutorhynchus assimilis Payk.) is one of the most important and dangerous pests of oilseed rape in Poland and in other European countries. In contrast to another important oilseed rape insect pest -pollen beetle (Meligethes aeneus F.), little is known about cabbage seed weevil susceptibility level to insecticide active ingredients. Therefore, the aim of this study was to determine the cabbage seed weevil susceptibility to active ingredients from different insecticide groups. Research, carried out in 2015, 2016 and 2017 revealed very high susceptibility of the pest to organophosphates and all pyrethroid active ingredients, except for tau-fluvalinate, lower susceptibility to thiacloprid and very high resistance to indoxacarb from oxadiazines. This information is a basic element for creating integrated pest management strategies for oilseed rape in Poland.

The Colorado potato beetle (Leptinotarsa decemlineata Say) (CPB) and the western corn rootworm (Diabrotica virgifera virgifera LeConte) (WCR) are both members of the Chrysomelidae family of beetles. The beetles are considered to be among the world's most expansive invasive species. They have spread rapidly and continue to spread to new areas, causing serious damage to economically important crops such as potato (CPB) and maize (WCR).The CPB is now established throughout most of North America, Europe, and many parts of Asia (CABI 2020). In the second half of the 20 th century, the spread of the CPB revolutionised the global phytopharmaceutical industry. The active substances of insecticides from different chemical groups were employed to manage the pest. Over the years, the pest has developed all the resistance mechanisms known in insects (i.e. physiological and behavioural resistance mechanisms as well as resistance mechanisms related to nervous tissue insensitivity) against the active substances of insecticides from all chemical groups that are used