ABSTRACT
Abstract The effect of different fungicides on mycorrhizal fungi should be investigated in different plants and environmental conditions. Thus, the purpose of this study was to appraise the effect of simultaneous fungicides application (including benomyl, rovral TS, mancozeb, and tilt) on the efficiency of Rhizophagus irregularis in cultivations of maize and wheat. This study was conducted in two separate experiments in the laboratory and greenhouse. The results of the laboratory stage showed that the use of all four fungicides significantly reduced the spore number compared to the conditions of non-use of the fungicide, although only rovral TS and mancozeb led to a significant reduction in root colonization percentage of R. irregularis. In the greenhouse, the benomyl significantly increased root dry weight in maize although tilt significantly reduced root colonization of maize with R. irregularis. The tilt and rovral TS had a positive effect and benomyl had a negative effect on wheat growth traits, but the root colonization of wheat with R. irregularis was not affected by fungicides. Generally, benomyl (2 g L-1) in maize and tilt (2 mL L-1) in wheat and rovral TS in both plants could be recommended with the combined application of R. irregularis inoculants. Therefore, depending on the type of fungicide and the host plant, the effect of the fungicide on colonization and association of mycorrhiza varies.