The influence of glucosinolates isolated from oilseed rape seeds on the growth of pathogenic fungi infecting oilseed rape was studied. The activity of those compounds against 3 fungal species was tested in vitro. It was stated that glucosinolates present in the medium did not totally inhibit the growth of the fungi, but considerably confined the area of colonies of 2 out of 3 fungal species studied.

The influence of oilseed rape glucosinolates on the grown in vitro pathogenic fungi was studied. Two pathogenic to oilseed rape fungi species: Fusarium roseum and Rhizoctonia so/ani were taken into consideration. It was observed that glucosinolates added to the medium limited the growth of both tested fungi to some extent, especially when higher concentrations of glucosinolates was supplied.

The species structure of plant parasitic nematode populations from the rhizosphere of winter wheat grown with crop rotation or in 48-year-old monoculture was analyzed and compared. Dominating species: Bitylenchus dubius, Merlinius microdorus, Paratylenchus neglectus and Heterodera avenae, in monoculture plots, had higher populations than in crop rotation plots. Heterodera avenae eggs and larvae were infected by pathogenic fungi in 68% of the monoculture crops (vs. 65–66% of the cysts from crop rotation), 12–20% of Paratylenchus sp. specimens were colonized by bacteria, mainly by Bacillus penetrans. This study shows nematological changes occurring in long-term wheat breeding, thus providing additional information necessary to fight dangerous viral vectors of the examined cereal.

The purpose of the studies carried out in the years 1996-1998 was to establish the composition of bacteria and fungi communities in the potato rhizosphere and non-rhizosphere soil. Besides, in the examined samples the studies established the proportion of bacteria and fungi antagonistic towards soilbome pathogens. The microbiological analysis of 1 g of dry weight of soil coming from the rhizosphere of potato revealed from 3.96 x 10' to 7 .26 x 10 6 bacteria colonies and from 51.38 x 103 to 69.96 x 103 fungi colonies. In the case of nonrhizosphere soil of 1 g of dry weight of soil revealed from 3.50 x 10' to 4.75 x 106 bacteria colonies and from 16.16 x 103 to 34.1 0 x 103 fungi colonies. Moreover, potato cultivation had a positive effect on the increase of numbers of antagonistic bacteria (Bacillus spp. and Pseudomonas spp.) and fungi (Gliocladium spp., Penicillium spp., Trichoderma spp.). A larger number of the communities of bacteria and fungi, including antagonistic ones, in the root area of potato, indicates considerable biological activity, which contributes to a better phytosanitary condition of the soil.

The aim of this study was to compare various methods of anti fungal activity determination in model experiments. For the investigations Bacillus coagulans (No. 6) isolate with the high anti fungal activity, isolated from lupine composts was used. Anti fungal activity of the examined isolate was estimated against five pathogenic species of fungi: Rhizoctonia so/ani, Bipolaris sorokiniana, Sclerotinia sclerotiorum, Trichothecium roseum and Fusarium oxysporum. Determination of fungal growth was carried out by three methods: ergosterol assessment, counting colony-forming units (CFU) and agar plate diffusion assay. Statistically significant Spearman's rank coefficients were recorded between ergosterol assessment and two other methods. On the basis of this data the assessment of ergosterol is the best way ofdetermination of antifungal activity and may be used as a reference procedure.