Rhizosphere microflora and colonization of wheat roots byGaeumannomyces graminis var.tritici after foliar application of urea and benomyl

The effect of foliar application of 2% urea and 0.6% benomyl on changes in colonization of the rhizosphere by microorganisms and of roots by the fungusGaeumannomyces graminis (Sacc.)Arx etOlivier var.tritici Walker was followed in vegetation glass-house experiments. Treatment with a urea solution resulted in increased counts of bacteria (82 %),Pseudomonas fluorescens (46 %),Agrobacterium sp. (31 %) and antagonistic bacteria with respect to the used fungus isolate and in a decreased occurrence of micromycetes (63 %). Treatment of wheat with a benomyl solution resulted in an increased count of bacteria (43 %) and a decreased occurrence ofP. fluorescens (16 %),Agrobacterium sp. (50 %) and fungi (67 %). After treatment with both compounds the infection of roots byG. graminis considerably decreased as compared with untreated plants. The results are discussed from the point of view of the effect of application of the studied compounds to upper parts of wheat on the microflora colonizing its roots.