RESEARCH OF THE PHYTOTOXIC EFFECT OF TEBUCONAZOLE, РROTHIOCONAZOLE, FLUDIOXONYL AND BASED ON THEM PRODUCTS ON THE GERMINATION POWER AND GROWTH OF SEEDLINGS OF WHEAT AND WHITE MUSTARD

The elaboration of new fungicidal protectants is an urgent issue due to the ability of pathogens to develop resistance. This fact contributes to the constant production of new protectants, so it carries an additional environmental impact. The main problem of development of new fungicides is choice of methods for identifying of optimal combinations and concentrations of fungicides. The optimization of the composition of fungicides is aimed to reduce the amount of active substances due to the synergistic effect. The use of fungicidal preparations with a reduced amount of active substances carries a lower environmental impact and gives a greater economic effect. One of the main problems in the application of fungicides is the phytotoxicity of the fungicides in relation to the protected plants. Phytotoxicity in general is the ability of pesticides or other substances to have a depressing (toxic) effect on plants. This problem is solved through researches of the germination of seedlings during the development of protectants. Researches of the germination power of seeds of soft winter wheat and white mustard after treatment with tebuconazole, рrothioconazole, and fludioxonyl were considered in the article. The main traits of the influence of the named substances on the germination of wheat grains and white mustard seeds, and morphological features of wheat seedlings, such as the length of their roots and shoots are revealed. In accordance to the results of the research, combinations of active substances (a.s.) that provide high effectiveness against the causative agents of diseases, and also do not have a phytotoxic effect on the protected culture have been determined. The aim of the work was the identification of traits of the phytotoxic effect of tebuconazole, рrothioconazole, fludioxonyl in the combination of seed protectants which are used to protect seedlings from plant diseases. Materials and methods. An assessment of the effect of three active substances of fungicides on wheat of the Grom cultivar and white mustard was given. The analysis was carried out in two replications for 48 possible combinations of tebuconazole, рrothioconazole, and fludioxonyl as well as fot two control variants. The ratio of normal, infected, abnormal and non-germinated seeds was analyzed. Results. According to the realized studies, tebuconazole has the greatest suppressive effect on germination and growth of shoots. Prothioconazole had no effect on germination, but it had a stimulating effect on the development and growth of wheat’s roots and shoots. With the combined action of prothioconazole and fludioxonyl, the greatest decrease in germination of wheat was observed. Conclusion. The possible phytotoxic effect, which depends on the dose of the protectant, should be taken into account when choosing a protectant and developing combined products. So the results of research demonstrated that the following combinations had no phytotoxic effect on protected plants: tebuconazole with рrothioconazole 5:10 and 5:15, tebuconazole with fludioxonyl 5:10, рrothioconazole with fludioxonyl 5:10.