Evaluation of the effect of different concentrations of fungicidal seed dressers Maxim KS and Delit Pro on the viability of B.elkanii pure cultures

The authors studied the effect of the toxic action of the fungicidal seed dressers Delit Pro (active substance – pyraclostrobin 200 g/l; BASF, USA) and Maxim KS (active substance – fludioxonil 25 g/l; Syngenta International AG, Switzerland) on the viability of the pure cultures of the B. elkanii species rhizobia bred by the All-Russian Research Institute of Soy. They studied the effect of three concentrations of these products (recommended/production, ½ of the recommended/production concentration and double recommended/production concentration) on the intensity of the growth of streak strains on the mannitol yeast agar nutrient medium on the 5th day after sowing. They identified a decrease in the intensity of the growth of streak strains on the nutrient medium vs. the control sample. They established that, despite the toxic effects of fungicides, most of the studied strains were resistant to the recommended/production concentrations of Delit Pro and Maxim KS. They analyzed the effect of the fungicidal seed dressers Delit Pro and Maxim KS on the formation of the symbiotic apparatus of soybeans in a series of laboratory experiments. They found out that the simultaneous treatment of soybean seeds with the pure cultures of nodule bacteria and seed dressers leads to some reduction in nodulation and virulence. They determined that the inhibitory effect of the fungicidal seed dressers Delit Pro and Maxim KS on the collection strains of the B.elkanii species rhizobia depends on the adaptive capabilities of the strain.