In a field experiment the susceptibility of yeast-like fungi to selected fungicides with the active ingredients (a.i.) propiconazole, epoxyconazole, kresoxim-methyl, fenpropimorph, carbendazim, prochloraz and flusilazole, was analyzed. The direct effect of the fungicides on the colonies of yeast-like fungi was determined based on antibiograms – the diffusion method. The survival rate of the isolates of yeast-like fungi on the leaves of winter wheat seedlings was determined in a phytotron. The fungicides Alert 375 SC and Bumper 250 EC inhibited the growth of yeast-like fungi most effectively, both under field conditions and in laboratory tests. Juwel TT 483 SE significantly reduced the abundance of Sporobolomyces roseus on both upper and lower leaves of wheat plants under in vivo conditions. The isolate of Pichia sp. was resistant to the tested fungicides.
Studies on sensitivity of microorganisms colonizing the leaves of winter wheat cultivar Almari to Amistar 250SC, Bravo 500SC fungicides and Bion 50WG plant resistance stimulator were performed in 2000-01. The studied fungicides decreased growth of hyphae fungi colonizing the leaves of winter wheat cultivated in pots, especially 24 hours after treatment, compared to control. Created free ecological niche was inhabited by bacteria and yeast-like fungi. From leaves treatment with Bion 50WG, the number of isolated microorganisms was bigger than control. In vitro fungicides Bravo 500SC and Amistar 250SC were very toxic to fungi Rhodotorula sp., Saccharomyces sp. and Cryptococcus sp. Colonizing the leaves of winter wheat. Bion 50WG plan resistance stimulator was toxic, but only in concentrations of 50 and 500 µg to Rhodotorula sp. Studied plant protection agents stimulated of strain Candida albicans.
The incidence of fusarium foot-rot occurrence on the winter wheat cultivars Roma and Sakwa was examined in the years 2001–2003. Strict plot experiments were set up by the method of random sub-blocks in Tomaszkowo near Olsztyn. Fungicides were applied on the growing plants during the periods of shooting and heading. The control plots were sprayed with water. The sanitary state of leaf sheaths was evaluated at heading phase (GS 55). The symptoms of fusarium foot-rot were examined at the phase of milky maturity (GS 75) and waxy maturity of grain (GS 87). The study aimed at assessing the average index of infection of the winter wheat stem base caused by the species of Fusarium genus, assessing the vulnerability of the Roma and Sakwa cultivars to these fungi and determining the effectiveness of pesticides in control of fusarium foot-rot. Fusarium foot-rot (Fusarium spp.) of winter wheat dominated on the winter wheat stem base. Most of the examined stems were severely infected. The Roma cultivar was more susceptible to infection by Fusarium fungi than the Sakwa cultivar. The effectiveness of fungicides in controlling fusarium foot-rot on the winter wheat was satisfactory, but largely depended on the cultivar and weather conditions. Mirage 450EC and Sportak Alpha 380EC fungicides were the most effective. The species F. culmorum and F. avenaceum dominated in the fungal populations colonizing the stem base of winter wheat with visible symptoms typical of fusarium foot-rot.