EFFECT OF FUNGICIDES ON THE EFFICIENCY OF SOYBEAN INOCULATION WITH PESTICIDE-RESISTANT NODULE BACTERIA

Abstract

Objective. Evaluate the efficiency of soybean inoculation with pesticide-resistant nodule bacteria Bradyrhizobium japonicum under the influence of pre-sowing seed dressing with Maxym XL,Standak Top and Fever and preventive spraying of plants with the fungicide Akanto Plus. Methods. Physiological, microbiological, gas chromatographic, vegetation experiment, statistical.Results. The number and weight of nodules formed on soybean roots during the growing seasonunder the action of the prothioconazole-based fungicide Fever were reported to be lower comparedwith the control and other variants of experiment. Pesticides Maxym XL and Standak Top had a lesspronounced toxic effect on the formation of legume-rhizobial symbiosis with the participation offungicide-resistant B. japonicum B78 Tn5 mutant compared to Fever. A decrease in the level of N2assimilation by 10.9–41.1 % in the three-leaf phase was found with the combined use of seed pesticides and nodule bacteria included in the study, relative to the variant with inoculation only. However, during the growing season, the negative effect of fungicidal preparations on the functioning oflegume-rhizobial symbiosis decreased. Conclusion. Under the conditions of the model vegetationexperiment with the concomitant use of Standak Top and Fever and bacterization, a decrease in individual plant productivity by 7.0 and 14.1 %, respectively, has been reported. The complex actionof the pesticide Maxym XL and inoculation with pesticide-resistant B. japonicum B78 transposonmutant, contributed to the maximum increase in yield by 27.2 %. The obtained data confirm the expediency of selection of fungicides and nitrogen-fixing microorganisms for concomitant use to ensure high economic and protective effects.